diff options
39 files changed, 3881 insertions, 264 deletions
diff --git a/CHICKEN.html.markdown b/CHICKEN.html.markdown index bb2f91f0..3f7cc2db 100644 --- a/CHICKEN.html.markdown +++ b/CHICKEN.html.markdown @@ -81,7 +81,7 @@ supports R5RS and R7RS (work in progress) standards and many extensions. (string-append "pine" "apple") ;; => "pineapple" (string-ref "tapioca" 3) ;; => #\i;; character 'i' is at index 3 (string->list "CHICKEN") ;; => (#\C #\H #\I #\C #\K #\E #\N) -(string->intersperse '("1" "2") ":") ;; => "1:2" +(string-intersperse '("1" "2") ":") ;; => "1:2" (string-split "1:2:3" ":") ;; => ("1" "2" "3") diff --git a/bash.html.markdown b/bash.html.markdown index 0c097c27..3f3e49eb 100644 --- a/bash.html.markdown +++ b/bash.html.markdown @@ -83,6 +83,25 @@ echo ${Foo:-"DefaultValueIfFooIsMissingOrEmpty"} # This works for null (Foo=) and empty string (Foo=""); zero (Foo=0) returns 0. # Note that it only returns default value and doesn't change variable value. +# Declare an array with 6 elements +array0=(one two three four five six) +# Print first element +echo $array0 # => "one" +# Print first element +echo ${array0[0]} # => "one" +# Print all elements +echo ${array0[@]} # => "one two three four five six" +# Print number of elements +echo ${#array0[@]} # => "6" +# Print number of characters in third element +echo ${#array0[2]} # => "5" +# Print 2 elements starting from forth +echo ${array0[@]:3:2} # => "four five" +# Print all elements. Each of them on new line. +for i in "${array0[@]}"; do + echo "$i" +done + # Brace Expansion { } # Used to generate arbitrary strings echo {1..10} # => 1 2 3 4 5 6 7 8 9 10 @@ -155,6 +174,13 @@ then echo "This will run if $Name is Daniya OR Zach." fi +# Redefine command 'ping' as alias to send only 5 packets +alias ping='ping -c 5' +# Escape alias and use command with this name instead +\ping 192.168.1.1 +# Print all aliases +alias -p + # Expressions are denoted with the following format: echo $(( 10 + 5 )) # => 15 diff --git a/c.html.markdown b/c.html.markdown index 87a047be..0c6df413 100644 --- a/c.html.markdown +++ b/c.html.markdown @@ -8,6 +8,7 @@ contributors: - ["Marco Scannadinari", "https://marcoms.github.io"] - ["Zachary Ferguson", "https://github.io/zfergus2"] - ["himanshu", "https://github.com/himanshu81494"] + - ["Joshua Li", "https://github.com/JoshuaRLi"] --- Ah, C. Still **the** language of modern high-performance computing. @@ -19,11 +20,12 @@ memory management and C will take you as far as you need to go. > **About compiler flags** > > By default, gcc and clang are pretty quiet about compilation warnings and -> errors, which can be very useful information. Using some -> stricter compiler flags is recommended. Here is an example you can -> tweak to your liking: +> errors, which can be very useful information. Explicitly using stricter +> compiler flags is recommended. Here are some recommended defaults: > -> `-Wall -Wextra -Werror -O0 -ansi -pedantic -std=c11` +> `-Wall -Wextra -Werror -O2 -std=c99 -pedantic` +> +> For information on what these flags do as well as other flags, consult the man page for your C compiler (e.g. `man 1 gcc`) or just search online. ```c // Single-line comments start with // - only available in C99 and later. diff --git a/crystal.html.markdown b/crystal.html.markdown index ad9cf0f8..8210b443 100644 --- a/crystal.html.markdown +++ b/crystal.html.markdown @@ -301,7 +301,6 @@ end (1..3).each do |index| puts "Index: #{index}" end -# Index: 0 # Index: 1 # Index: 2 # Index: 3 diff --git a/de-de/dynamic-programming-de.html.markdown b/de-de/dynamic-programming-de.html.markdown new file mode 100644 index 00000000..801d2514 --- /dev/null +++ b/de-de/dynamic-programming-de.html.markdown @@ -0,0 +1,77 @@ +--- +category: Algorithms & Data Structures +name: Dynamic Programming +contributors: + - ["Akashdeep Goel", "http://github.com/akashdeepgoel"] +translators: + - ["Henrik Jürges", "http://github.com/santifa"] +lang: de-de +--- + +# Dynamische Programmierung + +## Einführung +Dynamische Programmierung ist eine leistungsfähige Technik, die zur Lösung +einer bestimmten Klasse von Problemen verwendet wird. +Die Idee ist sehr einfach, wenn Sie ein Problem mit der gegebenen Eingabe +gelöst haben, dann speichern Sie das Ergebnis für die spätere Referenz, um zu +vermeiden, das gleiche Problem noch einmal zu lösen. + +Denken Sie immer daran! +"Diejenigen, die sich nicht an die Vergangenheit erinnern können, +sind dazu verdammt, sie zu wiederholen." + +## Wege zur Lösung solcher Probleme + +1. *Top-Down*: Lösen Sie das gegebene Problem, indem Sie es aufteilen. +Wenn Sie sehen, dass das Problem bereits gelöst ist, geben Sie einfach die +gespeicherte Antwort zurück. Wenn es nicht gelöst wurde, lösen Sie es und +speichern Sie die Antwort. Dieser Ansatz ist leicht zu verfolgen und sehr +intuitiv. Er wird als Memoization bezeichnet. + +2. *Bottom-Up*: Analysieren Sie das Problem und beobachten Sie, in welcher +Reihenfolge die Teilprobleme gelöst werden können. Beginnen Sie mit der +Lösung vom trivialen Teilproblem bis zum gegebenen Problem. Dabei wird +sichergestellt, dass die Teilprobleme vor der Problemlösung gelöst werden. +Dies wird als Dynamische Programmierung bezeichnet. + +## Ein Beispiel für Dynamische Programmierung + +Das Problem mit der längsten ansteigenden Subsequenz besteht darin, +die längste ansteigende Subsequenz einer gegebenen Sequenz zu finden. +Gegeben die Sequenz `S= {a1, a2, a3, a3, a4,..............., an-1, an }`, +müssen wir die größte Teilmenge finden, so daß für alle `j` und `i`, `j<i` +in der Teilmenge `aj<ai` gilt. +Zuerst müssen wir bei jedem Index i den Wert der längsten Subsequenzen (LSi) +finden, wobei das letzte Element der Sequenz ai ist. Dann wäre die größte LSi +die längste Subsequenz in der gegebenen Sequenz. Am Anfang wird der LSi mit +eins belegt, da ai ein Element der Sequenz (Letztes Element) ist. +Dann ist für alle `j` mit `j<i` und `aj<ai`, so dass wir den größten LSj finden +und zum LSi hinzufügen. Der Algorithmus hat eine Laufzeit von *O(n2)*. + +Pseudocode zur Bestimmung der Länge der am längsten ansteigenden Subsequenz: +Die Komplexität des Algorithmus könnte durch eine bessere Datenstruktur anstelle +von Arrays reduziert werden. Das Speichern von Vorgänger-Array's und Variablen +wie `largest_sequences_so_far` und dessen Index würde eine Menge Zeit sparen. + +Ein ähnliches Konzept könnte auch bei der Suche nach dem längsten Weg +in gerichteten azyklischen Graphen angewandt werden. +```python +for i=0 to n-1 + LS[i]=1 + for j=0 to i-1 + if (a[i] > a[j] and LS[i]<LS[j]) + LS[i] = LS[j]+1 +for i=0 to n-1 + if (largest < LS[i]) +``` + +### Einige bekannte DP Probleme + +- Floyd Warshall Algorithm - [Tutorial and C Program source code](http://www.thelearningpoint.net/computer-science/algorithms-all-to-all-shortest-paths-in-graphs---floyd-warshall-algorithm-with-c-program-source-code) +- Integer Knapsack Problem - [Tutorial and C Program source code](http://www.thelearningpoint.net/computer-science/algorithms-dynamic-programming---the-integer-knapsack-problem) +- Longest Common Subsequence - [Tutorial and C Program source code](http://www.thelearningpoint.net/computer-science/algorithms-dynamic-programming---longest-common-subsequence) + +## Online Ressourcen + +* [codechef](https://www.codechef.com/wiki/tutorial-dynamic-programming) diff --git a/de-de/go-de.html.markdown b/de-de/go-de.html.markdown index 817cb4ae..9409e181 100644 --- a/de-de/go-de.html.markdown +++ b/de-de/go-de.html.markdown @@ -94,7 +94,7 @@ Zeilenumbrüche beinhalten.` // Selber Zeichenketten-Typ // Arrays haben bei Kompile-Zeit festgelegte Größen var a4 [4]int // Ein Array mit 4 ints, alle mit Initialwert 0 - a3 := [...]int{3, 1, 5} // Ein Array mit 4 ints, Initialwerte wie angezeigt + a3 := [...]int{3, 1, 5} // Ein Array mit 3 ints, Initialwerte wie angezeigt // "slices" haben eine dynamische Größe. Arrays und Slices haben beide ihre // Vorzüge, aber slices werden viel häufiger verwendet diff --git a/de-de/make-de.html.markdown b/de-de/make-de.html.markdown index 22c14a69..bc5c7bcb 100644 --- a/de-de/make-de.html.markdown +++ b/de-de/make-de.html.markdown @@ -2,6 +2,7 @@ language: make
contributors:
- ["Robert Steed", "https://github.com/robochat"]
+ - ["Stephan Fuhrmann", "https://github.com/sfuhrm"]
translators:
- ["Martin Schimandl", "https://github.com/Git-Jiro"]
filename: Makefile-de
@@ -58,7 +59,7 @@ file2.txt file3.txt: file0.txt file1.txt touch file3.txt
# Make wird sich beschweren wenn es mehrere Rezepte für die gleiche Regel gibt.
-# Leere Rezepte zählen nicht und können dazu verwendet werden weitere
+# Leere Rezepte zählen nicht und können dazu verwendet werden weitere
# Voraussetzungen hinzuzufügen.
#-----------------------------------------------------------------------
@@ -182,9 +183,9 @@ echo: name2 = Sara # Wahr innerhalb der passenden Regel und auch innerhalb # Ein paar Variablen die von Make automatisch definiert werden.
echo_inbuilt:
echo $(CC)
- echo ${CXX)}
+ echo ${CXX}
echo $(FC)
- echo ${CFLAGS)}
+ echo ${CFLAGS}
echo $(CPPFLAGS)
echo ${CXXFLAGS}
echo $(LDFLAGS)
diff --git a/fr-fr/bf-fr.html.markdown b/fr-fr/bf-fr.html.markdown index 0fae6032..d8c7c76a 100644 --- a/fr-fr/bf-fr.html.markdown +++ b/fr-fr/bf-fr.html.markdown @@ -1,5 +1,5 @@ --- -language: bf +language: Brainfuck filename: learnbrainfuck-fr.bf contributors: - ["Prajit Ramachandran", "http://prajitr.github.io/"] diff --git a/fr-fr/crystal-fr.html.markdown b/fr-fr/crystal-fr.html.markdown index 2c4e3dad..2bb17fc5 100644 --- a/fr-fr/crystal-fr.html.markdown +++ b/fr-fr/crystal-fr.html.markdown @@ -305,7 +305,6 @@ end (1..3).each do |index| puts "Index: #{index}" end -# Index: 0 # Index: 1 # Index: 2 # Index: 3 diff --git a/go.html.markdown b/go.html.markdown index e5263cf6..47d9c234 100644 --- a/go.html.markdown +++ b/go.html.markdown @@ -180,7 +180,7 @@ func learnFlowControl() { if true { fmt.Println("told ya") } - // Formatting is standardized by the command line command "go fmt." + // Formatting is standardized by the command line command "go fmt". if false { // Pout. } else { diff --git a/hu-hu/python-hu.html.markdown b/hu-hu/python-hu.html.markdown new file mode 100644 index 00000000..9b55f8e2 --- /dev/null +++ b/hu-hu/python-hu.html.markdown @@ -0,0 +1,816 @@ +--- +language: python +contributors: + - ["Louie Dinh", "http://ldinh.ca"] + - ["Amin Bandali", "https://aminb.org"] + - ["Andre Polykanine", "https://github.com/Oire"] + - ["evuez", "http://github.com/evuez"] + - ["asyne", "https://github.com/justblah"] + - ["habi", "http://github.com/habi"] +translators: + - ["Tamás Diószegi", "https://github.com/ditam"] +filename: learnpython-hu.py +lang: hu-hu +--- + +A Python nyelvet Guido Van Rossum alkotta meg a 90-es évek elején. Manapság az +egyik legnépszerűbb programozási nyelv. Én a tiszta szintaxisa miatt szerettem +bele. Tulajdonképpen futtatható pszeudokód. + +Szívesen fogadok visszajelzéseket! Elérsz itt: [@louiedinh](http://twitter.com/louiedinh) +vagy pedig a louiedinh [kukac] [google email szolgáltatása] címen. + +Figyelem: ez a leírás a Python 2.7 verziójára vonatkozok, illetve +általánosságban a 2.x verziókra. A Python 2.7 azonban már csak 2020-ig lesz +támogatva, ezért kezdőknek ajánlott, hogy a Python 3-mal kezdjék az +ismerkedést. A Python 3.x verzióihoz a [Python 3 bemutató](http://learnxinyminutes.com/docs/python3/) +ajánlott. + +Lehetséges olyan Python kódot írni, ami egyszerre kompatibilis a 2.7 és a 3.x +verziókkal is, a Python [`__future__` imports](https://docs.python.org/2/library/__future__.html) használatával. +A `__future__` import használata esetén Python 3-ban írhatod a kódot, ami +Python 2 alatt is futni fog, így ismét a fenti Python 3 bemutató ajánlott. + +```python + +# Az egysoros kommentek kettőskereszttel kezdődnek + +""" Többsoros stringeket három darab " közé + fogva lehet írni, ezeket gyakran használják + több soros kommentként. +""" + +#################################################### +# 1. Egyszerű adattípusok és operátorok +#################################################### + +# Használhatsz számokat +3 # => 3 + +# Az alapműveletek meglepetésektől mentesek +1 + 1 # => 2 +8 - 1 # => 7 +10 * 2 # => 20 +35 / 5 # => 7 + +# Az osztás kicsit trükkös. Egész osztást végez, és a hányados alsó egész része +# lesz az eredmény +5 / 2 # => 2 + +# Az osztás kijavításához a (lebegőpontos) float típust kell használnunk +2.0 # Ez egy float +11.0 / 4.0 # => 2.75 áh... máris jobb + +# Az egész osztás a negatív számok esetén is az alsó egész részt eredményezi +5 // 3 # => 1 +5.0 // 3.0 # => 1.0 # floatok esetén is +-5 // 3 # => -2 +-5.0 // 3.0 # => -2.0 + +# Ha importáljuk a division modult (ld. 6. Modulok rész), +# akkor a '/' jellel pontos osztást tudunk végezni. +from __future__ import division + +11 / 4 # => 2.75 ...sima osztás +11 // 4 # => 2 ...egész osztás + +# Modulo művelet +7 % 3 # => 1 + +# Hatványozás (x az y. hatványra) +2 ** 4 # => 16 + +# A precedencia zárójelekkel befolyásolható +(1 + 3) * 2 # => 8 + +# Logikai operátorok +# Megjegyzés: az "and" és "or" csak kisbetűkkel helyes +True and False # => False +False or True # => True + +# A logikai operátorok egészeken is használhatóak +0 and 2 # => 0 +-5 or 0 # => -5 +0 == False # => True +2 == True # => False +1 == True # => True + +# Negálni a not kulcsszóval lehet +not True # => False +not False # => True + +# Egyenlőségvizsgálat == +1 == 1 # => True +2 == 1 # => False + +# Egyenlőtlenség != +1 != 1 # => False +2 != 1 # => True + +# További összehasonlítások +1 < 10 # => True +1 > 10 # => False +2 <= 2 # => True +2 >= 2 # => True + +# Az összehasonlítások láncolhatóak! +1 < 2 < 3 # => True +2 < 3 < 2 # => False + +# Stringeket " vagy ' jelek közt lehet megadni +"Ez egy string." +'Ez egy másik string.' + +# A stringek összeadhatóak! +"Hello " + "world!" # => "Hello world!" +# '+' jel nélkül is összeadhatóak +"Hello " "world!" # => "Hello world!" + +# ... illetve szorozhatóak +"Hello" * 3 # => "HelloHelloHello" + +# Kezelhető karakterek indexelhető listájaként +"This is a string"[0] # => 'T' + +# A string hosszát a len függvény adja meg +len("This is a string") # => 16 + +# String formázáshoz a % jel használható +# A Python 3.1-gyel a % már deprecated jelölésű, és később eltávolításra fog +# kerülni, de azért jó tudni, hogyan működik. +x = 'alma' +y = 'citrom' +z = "A kosárban levő elemek: %s és %s" % (x, y) + +# A string formázás újabb módja a format metódus használatával történik. +# Jelenleg ez a javasolt megoldás. +"{} egy {} szöveg".format("Ez", "helytartó") +"A {0} pedig {1}".format("string", "formázható") +# Ha nem akarsz számolgatni, nevesíthetőek a pozíciók. +"{name} kedvence a {food}".format(name="Bob", food="lasagna") + +# None egy objektum +None # => None + +# A None-nal való összehasonlításhoz ne használd a "==" jelet, +# használd az "is" kulcsszót helyette +"etc" is None # => False +None is None # => True + +# Az 'is' operátor objektum egyezést vizsgál. +# Primitív típusok esetén ez nem túl hasznos, +# objektumok esetén azonban annál inkább. + +# Bármilyen objektum használható logikai kontextusban. +# A következő értékek hamis-ra értékelődnek ki (ún. "falsey" értékek): +# - None +# - bármelyik szám típus 0 értéke (pl. 0, 0L, 0.0, 0j) +# - üres sorozatok (pl. '', (), []) +# - üres konténerek (pl., {}, set()) +# - egyes felhasználó által definiált osztályok példányai bizonyos szabályok szerint, +# ld: https://docs.python.org/2/reference/datamodel.html#object.__nonzero__ +# +# Minden egyéb érték "truthy" (a bool() függvénynek átadva igazra értékelődnek ki) +bool(0) # => False +bool("") # => False + + +#################################################### +# 2. Változók és kollekciók +#################################################### + +# Létezik egy print utasítás +print "I'm Python. Nice to meet you!" # => I'm Python. Nice to meet you! + +# Így lehet egyszerűen bemenetet kérni a konzolról: +input_string_var = raw_input( + "Enter some data: ") # Visszatér a megadott stringgel +input_var = input("Enter some data: ") # Kiértékeli a bemenetet python kódként +# Vigyázat: a fentiek miatt az input() metódust körültekintően kell használni +# Megjegyzés: Python 3-ban az input() már deprecated, és a raw_input() lett input()-ra átnevezve + +# A változókat nem szükséges a használat előtt deklarálni +some_var = 5 # Konvenció szerint a névben kisbetu_es_alulvonas +some_var # => 5 + +# Érték nélküli változóra hivatkozás hibát dob. +# Lásd a Control Flow szekciót a kivételkezelésről. +some_other_var # name error hibát dob + +# az if használható kifejezésként +# a C nyelv '?:' ternáris operátorával egyenértékűen +"yahoo!" if 3 > 2 else 2 # => "yahoo!" + +# A listákban sorozatok tárolhatóak +li = [] +# Már inicializáláskor megadhatóak elemek +other_li = [4, 5, 6] + +# A lista végére az append metódus rak új elemet +li.append(1) # li jelenleg [1] +li.append(2) # li jelenleg [1, 2] +li.append(4) # li jelenleg [1, 2, 4] +li.append(3) # li jelenleg [1, 2, 4, 3] +# A végéről a pop metódus távolít el elemet +li.pop() # => 3 és li jelenleg [1, 2, 4] +# Rakjuk vissza +li.append(3) # li jelenleg [1, 2, 4, 3], újra. + +# A lista elemeket tömb indexeléssel lehet hivatkozni +li[0] # => 1 +# A már inicializált értékekhez a = jellel lehet új értéket rendelni +li[0] = 42 +li[0] # => 42 +li[0] = 1 # csak visszaállítjuk az eredeti értékére +# Így is lehet az utolsó elemre hivatkozni +li[-1] # => 3 + +# A túlindexelés eredménye IndexError +li[4] # IndexError hibát dob + +# A lista részeit a slice szintaxissal lehet kimetszeni +# (Matekosoknak ez egy zárt/nyitott intervallum.) +li[1:3] # => [2, 4] +# A lista eleje kihagyható így +li[2:] # => [4, 3] +# Kihagyható a vége +li[:3] # => [1, 2, 4] +# Minden második elem kiválasztása +li[::2] # =>[1, 4] +# A lista egy másolata, fordított sorrendben +li[::-1] # => [3, 4, 2, 1] +# A fentiek kombinációival bonyolultabb slice parancsok is képezhetőek +# li[start:end:step] + +# Listaelemek a "del" paranccsal törölhetőek +del li[2] # li jelenleg [1, 2, 3] + +# A listák összeadhatóak +li + other_li # => [1, 2, 3, 4, 5, 6] +# Megjegyzés: az eredeti li és other_li értékei változatlanok + +# Összefőzhetőek (konkatenálhatóak) az "extend()" paranccsal +li.extend(other_li) # li jelenleg [1, 2, 3, 4, 5, 6] + +# Egy elem első előfordulásának eltávolítása +li.remove(2) # li jelenleg [1, 3, 4, 5, 6] +li.remove(2) # ValueError hibát dob, mivel a 2 nem szerepel már a listában + +# Elemek beszúrhatóak tetszőleges helyre +li.insert(1, 2) # li jelenleg [1, 2, 3, 4, 5, 6], ismét + +# Egy elem első előfordulási helye +li.index(2) # => 1 +li.index(7) # ValueError hibát dob, mivel a 7 nem szerepel a listában + +# Egy listában egy elem előfordulása az "in" szóval ellenőrizhető +1 in li # => True + +# A lista hossza a "len()" függvénnyel +len(li) # => 6 + +# Az N-esek ("tuple") hasonlítanak a listákhoz, de nem módosíthatóak +tup = (1, 2, 3) +tup[0] # => 1 +tup[0] = 3 # TypeError hibát dob + +# Az összes lista-műveletet ezeken is használható +len(tup) # => 3 +tup + (4, 5, 6) # => (1, 2, 3, 4, 5, 6) +tup[:2] # => (1, 2) +2 in tup # => True + +# Az N-esek (és listák) kicsomagolhatóak külön változókba +a, b, c = (1, 2, 3) # az a így 1, a b 2 és a c pedig 3 +d, e, f = 4, 5, 6 # a zárójel elhagyható +# Ha elhagyod a zárójeleket, alapértelmezés szerint tuple képződik +g = 4, 5, 6 # => (4, 5, 6) +# Nézd, milyen egyszerű két értéket megcserélni +e, d = d, e # d most már 5 és az e 4 + +# A Dictionary típusokban hozzárendelések (kulcs-érték párok) tárolhatók +empty_dict = {} +# Ez pedig rögtön értékekkel van inicializálva +filled_dict = {"one": 1, "two": 2, "three": 3} + +# Egy dictionary értékei [] jelek közt indexelhetőek +filled_dict["one"] # => 1 + +# A "keys()" metódus visszatér a kulcsok listájával +filled_dict.keys() # => ["three", "two", "one"] +# Megjegyzés: egy dictionary párjainak sorrendje nem garantált +# Lehet, hogy már a fenti példán is más sorrendben kaptad meg az elemeket. + +# Az értékek listája a "values()" metódussal kérhető le +filled_dict.values() # => [3, 2, 1] +# ld. a fenti megjegyzést az elemek sorrendjéről. + +# Az összes kulcs-érték pár megkapható N-esek listájaként az "items()" metódussal +filled_dict.items() # => [("one", 1), ("two", 2), ("three", 3)] + +# Az "in" kulcssszóval ellenőrizhető, hogy egy kulcs szerepel-e a dictionary-ben +"one" in filled_dict # => True +1 in filled_dict # => False + +# Nem létező kulcs hivatkozása KeyError hibát dob +filled_dict["four"] # KeyError + +# A "get()" metódus használatával elkerülhető a KeyError +filled_dict.get("one") # => 1 +filled_dict.get("four") # => None +# A metódusnak megadható egy alapértelmezett visszatérési érték is, hiányzó értékek esetén +filled_dict.get("one", 4) # => 1 +filled_dict.get("four", 4) # => 4 +# Megjegyzés: ettől még filled_dict.get("four") => None +# (vagyis a get nem állítja be az alapértelmezett értéket a dictionary-ben) + +# A kulcsokhoz értékek a listákhoz hasonló szintaxissal rendelhetőek: +filled_dict["four"] = 4 # ez után filled_dict["four"] => 4 + +# A "setdefault()" metódus csak akkor állít be egy értéket, ha az adott kulcshoz még nem volt más megadva +filled_dict.setdefault("five", 5) # filled_dict["five"] beállítva 5-re +filled_dict.setdefault("five", 6) # filled_dict["five"] még mindig 5 + +# Egy halmaz ("set") olyan, mint egy lista, de egy elemet csak egyszer tárolhat +empty_set = set() +# Inicializáljuk ezt a halmazt néhány elemmel +some_set = set([1, 2, 2, 3, 4]) # some_set jelenleg set([1, 2, 3, 4]) + +# A sorrend itt sem garantált, még ha néha rendezettnek is tűnhet +another_set = set([4, 3, 2, 2, 1]) # another_set jelenleg set([1, 2, 3, 4]) + +# Python 2.7 óta már {} jelek közt is lehet halmazt definiálni +filled_set = {1, 2, 2, 3, 4} # => {1, 2, 3, 4} + +# Új halmaz-elemek hozzáadása +filled_set.add(5) # filled_set is now {1, 2, 3, 4, 5} + +# Halmaz metszés a & operátorral +other_set = {3, 4, 5, 6} +filled_set & other_set # => {3, 4, 5} + +# Halmaz unió | operátorral +filled_set | other_set # => {1, 2, 3, 4, 5, 6} + +# Halmaz különbség - +{1, 2, 3, 4} - {2, 3, 5} # => {1, 4} + +# Szimmetrikus differencia ^ +{1, 2, 3, 4} ^ {2, 3, 5} # => {1, 4, 5} + +# Vizsgáljuk, hogy a bal oldali halmaz magában foglalja-e a jobb oldalit +{1, 2} >= {1, 2, 3} # => False + +# Vizsgáljuk, hogy a bal oldali halmaz részhalmaza-e a jobb oldalinak +{1, 2} <= {1, 2, 3} # => True + +# Halmazbeli elemek jelenléte az in kulcssszóval vizsgálható +2 in filled_set # => True +10 in filled_set # => False + + +#################################################### +# 3. Control Flow +#################################################### + +# Legyen egy változónk +some_var = 5 + +# Ez egy if elágazás. A behúzás mértéke (az indentáció) jelentéssel bír a nyelvben! +# Ez a kód ezt fogja kiírni: "some_var kisebb 10-nél" +if some_var > 10: + print "some_var nagyobb, mint 10." +elif some_var < 10: # Az elif kifejezés nem kötelező az if szerkezetben. + print "some_var kisebb 10-nél" +else: # Ez sem kötelező. + print "some_var kereken 10." + +""" +For ciklusokkal végigiterálhatunk listákon +a kimenet: + A(z) kutya emlős + A(z) macska emlős + A(z) egér emlős +""" +for animal in ["kutya", "macska", "egér"]: + # A {0} kifejezéssel formázzuk a stringet, ld. korábban. + print "A(z) {0} emlős".format(animal) + +""" +"range(number)" visszatér számok listájával 0-től number-ig +a kimenet: + 0 + 1 + 2 + 3 +""" +for i in range(4): + print i + +""" +"range(lower, upper)" visszatér a lower és upper közti számok listájával +a kimenet: + 4 + 5 + 6 + 7 +""" +for i in range(4, 8): + print i + +""" +A while ciklus a feltétel hamissá válásáig fut. +a kimenet: + 0 + 1 + 2 + 3 +""" +x = 0 +while x < 4: + print x + x += 1 # Rövidítés az x = x + 1 kifejezésre + +# A kivételek try/except blokkokkal kezelhetőek + +# Python 2.6-tól felfele: +try: + # A "raise" szóval lehet hibát dobni + raise IndexError("Ez egy index error") +except IndexError as e: + pass # A pass egy üres helytartó művelet. Itt hívnánk a hibakezelő kódunkat. +except (TypeError, NameError): + pass # Ha szükséges, egyszerre több hiba típus is kezelhető +else: # Az except blokk után opcionálisan megadható + print "Minden rendben!" # Csak akkor fut le, ha fentebb nem voltak hibák +finally: # Mindenképpen lefut + print "Itt felszabadíthatjuk az erőforrásokat például" + +# Az erőforrások felszabadításához try/finally helyett a with használható +with open("myfile.txt") as f: + for line in f: + print line + + +#################################################### +# 4. Függvények +#################################################### + +# A "def" szóval hozhatunk létre új függvényt +def add(x, y): + print "x is {0} and y is {1}".format(x, y) + return x + y # A return szóval tudunk értékeket visszaadni + + +# Így hívunk függvényt paraméterekkel +add(5, 6) # => a konzol kimenet "x is 5 and y is 6", a visszatérési érték 11 + +# Nevesített paraméterekkel (ún. "keyword arguments") is hívhatunk egy függvényt +add(y=6, x=5) # Ez esetben a sorrendjük nem számít + + +# Változó számú paramétert fogadó függvény így definiálható. +# A * használatával a paramétereket egy N-esként kapjuk meg. +def varargs(*args): + return args + + +varargs(1, 2, 3) # => (1, 2, 3) + + +# Változó számú nevesített paramétert fogadó függvény is megadható, +# a ** használatával a paramétereket egy dictionary-ként kapjuk meg +def keyword_args(**kwargs): + return kwargs + + +# Nézzük meg, mi történik +keyword_args(big="foot", loch="ness") # => {"big": "foot", "loch": "ness"} + + +# A két módszer egyszerre is használható +def all_the_args(*args, **kwargs): + print args + print kwargs + + +""" +all_the_args(1, 2, a=3, b=4) kimenete: + (1, 2) + {"a": 3, "b": 4} +""" + +# Függvények hívásakor a fenti args és kwargs módszerek inverze használható +# A * karakter kifejt egy listát külön paraméterekbe, a ** egy dictionary-t nevesített paraméterekbe. +args = (1, 2, 3, 4) +kwargs = {"a": 3, "b": 4} +all_the_args(*args) # egyenértékű: foo(1, 2, 3, 4) +all_the_args(**kwargs) # egyenértékű: foo(a=3, b=4) +all_the_args(*args, **kwargs) # egyenértékű: foo(1, 2, 3, 4, a=3, b=4) + + +# A fenti arg és kwarg paraméterek továbbadhatóak egyéb függvényeknek, +# a * illetve ** operátorokkal kifejtve +def pass_all_the_args(*args, **kwargs): + all_the_args(*args, **kwargs) + print varargs(*args) + print keyword_args(**kwargs) + + +# Függvény scope +x = 5 + + +def set_x(num): + # A lokális x változó nem ugyanaz, mint a globális x + x = num # => 43 + print x # => 43 + + +def set_global_x(num): + global x + print x # => 5 + x = num # a globális x-et 6-ra állítjuk + print x # => 6 + + +set_x(43) +set_global_x(6) + + +# A pythonban a függvény elsőrendű (ún. "first class") típus +def create_adder(x): + def adder(y): + return x + y + + return adder + + +add_10 = create_adder(10) +add_10(3) # => 13 + +# Névtelen függvények is definiálhatóak +(lambda x: x > 2)(3) # => True +(lambda x, y: x ** 2 + y ** 2)(2, 1) # => 5 + +# Léteznek beépített magasabb rendű függvények +map(add_10, [1, 2, 3]) # => [11, 12, 13] +map(max, [1, 2, 3], [4, 2, 1]) # => [4, 2, 3] + +filter(lambda x: x > 5, [3, 4, 5, 6, 7]) # => [6, 7] + +# A listaképző kifejezések ("list comprehensions") jól használhatóak a map és filter függvényekkel +[add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] +[x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7] + +# halmaz és dictionary képzők is léteznek +{x for x in 'abcddeef' if x in 'abc'} # => {'a', 'b', 'c'} +{x: x ** 2 for x in range(5)} # => {0: 0, 1: 1, 2: 4, 3: 9, 4: 16} + + +#################################################### +# 5. Osztályok +#################################################### + +# Az object osztály egy alosztályát képezzük +class Human(object): + # Osztály szintű mező: az osztály összes példányában azonos + species = "H. sapiens" + + # Ez a függvény meghívódik az osztály példányosításakor. + # Megjegyzés: a dupla aláhúzás a név előtt és után egy konvenció a python + # előre definiált, a nyelv által belsőleg használt, de a felhasználó által + # is látható objektumok és mezők neveire. + # Ne vezessünk be új, ilyen elnevezési sémát használó neveket! + def __init__(self, name): + # A paramétert értékül adjuk a példány name attribútumának + self.name = name + + # Inicializálunk egy mezőt + self.age = 0 + + # Példány metódus. Minden metódus első paramétere a "self", a példány maga + def say(self, msg): + return "{0}: {1}".format(self.name, msg) + + # Egy osztálymetódus az osztály összes példány közt meg van osztva. + # Hívásukkor az első paraméter mindig a hívó osztály. + @classmethod + def get_species(cls): + return cls.species + + # Egy statikus metódus osztály és példányreferencia nélkül hívódik + @staticmethod + def grunt(): + return "*grunt*" + + # Egy property jelölésű függvény olyan, mint egy getter. + # Használatával az age mező egy csak-olvasható attribútummá válik. + @property + def age(self): + return self._age + + # Így lehet settert megadni egy mezőhöz + @age.setter + def age(self, age): + self._age = age + + # Így lehet egy mező törlését engedélyezni + @age.deleter + def age(self): + del self._age + + +# Példányosítsuk az osztályt +i = Human(name="Ian") +print i.say("hi") # kimenet: "Ian: hi" + +j = Human("Joel") +print j.say("hello") # kimenet: "Joel: hello" + +# Hívjuk az osztály metódusunkat +i.get_species() # => "H. sapiens" + +# Változtassuk meg az osztály szintű attribútumot +Human.species = "H. neanderthalensis" +i.get_species() # => "H. neanderthalensis" +j.get_species() # => "H. neanderthalensis" + +# Hívjuk meg a statikus metódust +Human.grunt() # => "*grunt*" + +# Adjunk új értéket a mezőnek +i.age = 42 + +# Kérjük le a mező értékét +i.age # => 42 + +# Töröljük a mezőt +del i.age +i.age # => AttributeError hibát dob + +#################################################### +# 6. Modulok +#################################################### + +# Modulokat így lehet importálni +import math + +print math.sqrt(16) # => 4 + +# Lehetséges csak bizonyos függvényeket importálni egy modulból +from math import ceil, floor + +print ceil(3.7) # => 4.0 +print floor(3.7) # => 3.0 + +# Egy modul összes függvénye is importálható +# Vigyázat: ez nem ajánlott. +from math import * + +# A modulok nevei lerövidíthetőek +import math as m + +math.sqrt(16) == m.sqrt(16) # => True +# Meggyőződhetünk róla, hogy a függvények valóban azonosak +from math import sqrt + +math.sqrt == m.sqrt == sqrt # => True + +# A Python modulok egyszerű fájlok. +# Írhatsz sajátot és importálhatod is. +# A modul neve azonos a tartalmazó fájl nevével. + +# Így lehet megtekinteni, milyen mezőket és függvényeket definiál egy modul. +import math + +dir(math) + + +# Ha van egy math.py nevű Python scripted a jelenleg futó scripttel azonos +# mappában, a math.py fájl lesz betöltve a beépített Python modul helyett. +# A lokális mappa prioritást élvez a beépített könyvtárak felett. + + +#################################################### +# 7. Haladóknak +#################################################### + +# Generátorok +# Egy generátor értékeket "generál" amikor kérik, a helyett, hogy előre eltárolná őket. + +# A következő metódus (ez még NEM egy generátor) megduplázza a kapott iterable elemeit, +# és eltárolja őket. Nagy méretű iterable esetén ez nagyon sok helyet foglalhat! +def double_numbers(iterable): + double_arr = [] + for i in iterable: + double_arr.append(i + i) + return double_arr + + +# A következő kód futtatásakor az összes szám kétszeresét kiszámítanánk, és visszaadnánk +# ezt a nagy listát a ciklus vezérléséhez. +for value in double_numbers(range(1000000)): # `test_non_generator` + print value + if value > 5: + break + + +# Használjunk inkább egy generátort, ami "legenerálja" a soron következő elemet, +# amikor azt kérik tőle +def double_numbers_generator(iterable): + for i in iterable: + yield i + i + + +# A lenti kód mindig csak a soron következő számot generálja a logikai vizsgálat előtt. +# Így amikor az érték eléri a > 5 határt, megszakítjuk a ciklust, és a lista számainak +# nagy részénél megspóroltuk a duplázás műveletet (ez sokkal gyorsabb így!). +for value in double_numbers_generator(xrange(1000000)): # `test_generator` + print value + if value > 5: + break + +# Feltűnt, hogy a `test_non_generator` esetén `range`, a `test_generator` esetén +# pedig `xrange` volt a segédfüggvény neve? Ahogy `double_numbers_generator` a +# generátor változata a `double_numbers` függvénynek, úgy az `xrange` a `range` +# generátor megfelelője, csak akkor generálja le a következő számot, amikor kérjük +# - esetünkben a ciklus következő iterációjakor + +# A lista képzéshez hasonlóan generátor képzőket is használhatunk +# ("generator comprehensions"). +values = (-x for x in [1, 2, 3, 4, 5]) +for x in values: + print(x) # kimenet: -1 -2 -3 -4 -5 + +# Egy generátor összes generált elemét listaként is elkérhetjük: +values = (-x for x in [1, 2, 3, 4, 5]) +gen_to_list = list(values) +print(gen_to_list) # => [-1, -2, -3, -4, -5] + +# Dekorátorok +# A dekorátor egy magasabb rendű függvény, aminek bemenete és kimenete is egy függvény. +# A lenti egyszerű példában az add_apples dekorátor a dekorált get_fruits függvény +# kimenetébe beszúrja az 'Apple' elemet. +def add_apples(func): + def get_fruits(): + fruits = func() + fruits.append('Apple') + return fruits + return get_fruits + +@add_apples +def get_fruits(): + return ['Banana', 'Mango', 'Orange'] + +# A kimenet tartalmazza az 'Apple' elemet: +# Banana, Mango, Orange, Apple +print ', '.join(get_fruits()) + +# Ebben a példában a beg dekorátorral látjuk el a say függvényt. +# Beg meghívja say-t. Ha a say_please paraméter igaz, akkor +# megváltoztatja az eredmény mondatot. +from functools import wraps + + +def beg(target_function): + @wraps(target_function) + def wrapper(*args, **kwargs): + msg, say_please = target_function(*args, **kwargs) + if say_please: + return "{} {}".format(msg, "Please! I am poor :(") + return msg + + return wrapper + + +@beg +def say(say_please=False): + msg = "Can you buy me a beer?" + return msg, say_please + + +print say() # Can you buy me a beer? +print say(say_please=True) # Can you buy me a beer? Please! I am poor :( +``` + +## Még több érdekel? + +### Ingyenes online tartalmak + +* [Automate the Boring Stuff with Python](https://automatetheboringstuff.com) +* [Learn Python The Hard Way](http://learnpythonthehardway.org/book/) +* [Dive Into Python](http://www.diveintopython.net/) +* [The Official Docs](http://docs.python.org/2/) +* [Hitchhiker's Guide to Python](http://docs.python-guide.org/en/latest/) +* [Python Module of the Week](http://pymotw.com/2/) +* [A Crash Course in Python for Scientists](http://nbviewer.ipython.org/5920182) +* [First Steps With Python](https://realpython.com/learn/python-first-steps/) +* [LearnPython](http://www.learnpython.org/) +* [Fullstack Python](https://www.fullstackpython.com/) + +### Könyvek + +* [Programming Python](http://www.amazon.com/gp/product/0596158106/ref=as_li_qf_sp_asin_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596158106&linkCode=as2&tag=homebits04-20) +* [Dive Into Python](http://www.amazon.com/gp/product/1441413022/ref=as_li_tf_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1441413022&linkCode=as2&tag=homebits04-20) +* [Python Essential Reference](http://www.amazon.com/gp/product/0672329786/ref=as_li_tf_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0672329786&linkCode=as2&tag=homebits04-20) diff --git a/java.html.markdown b/java.html.markdown index dd875c16..ab2be4a2 100644 --- a/java.html.markdown +++ b/java.html.markdown @@ -44,8 +44,6 @@ import java.util.ArrayList; // Import all classes inside of java.security package import java.security.*; -// Each .java file contains one outer-level public class, with the same name -// as the file. public class LearnJava { // In order to run a java program, it must have a main method as an entry diff --git a/julia.html.markdown b/julia.html.markdown index 85033aa6..9e28452f 100644 --- a/julia.html.markdown +++ b/julia.html.markdown @@ -98,7 +98,7 @@ false # You can put any Julia expression inside the parentheses. # Another way to format strings is the printf macro. -@printf "%d is less than %f" 4.5 5.3 # 5 is less than 5.300000 +@printf "%d is less than %f" 4.5 5.3 # 4.5 is less than 5.300000 # Printing is easy println("I'm Julia. Nice to meet you!") diff --git a/kdb+.html.markdown b/kdb+.html.markdown index 5ae86a4f..097f177b 100644 --- a/kdb+.html.markdown +++ b/kdb+.html.markdown @@ -76,7 +76,7 @@ floor 3.14159 / => 3 / ...getting the absolute value... abs -3.14159 / => 3.14159 / ...and many other things -/ see http://code.kx.com/wiki/Reference for more +/ see http://code.kx.com/q/ref/card/ for more / q has no operator precedence, everything is evaluated right to left / so results like this might take some getting used to @@ -174,7 +174,7 @@ t - 00:10:00.000 / => 00:50:00.000 d.year / => 2015i d.mm / => 12i d.dd / => 25i -/ see http://code.kx.com/wiki/JB:QforMortals2/atoms#Temporal_Data for more +/ see http://code.kx.com/q4m3/2_Basic_Data_Types_Atoms/#25-temporal-data for more / q also has an infinity value so div by zero will not throw an error 1%0 / => 0w @@ -183,7 +183,7 @@ d.dd / => 25i / And null types for representing missing values 0N / => null int 0n / => null float -/ see http://code.kx.com/wiki/JB:QforMortals2/atoms#Null_Values for more +/ see http://code.kx.com/q4m3/2_Basic_Data_Types_Atoms/#27-nulls for more / q has standard control structures / if is as you might expect (; separates the condition and instructions) @@ -642,7 +642,7 @@ kt upsert ([]name:`Thomas`Chester;age:33 58;height:175 179;sex:`f`m) / => Thomas 32 175 m / Most of the standard SQL joins are present in q-sql, plus a few new friends -/ see http://code.kx.com/wiki/JB:QforMortals2/queries_q_sql#Joins +/ see http://code.kx.com/q4m3/9_Queries_q-sql/#99-joins / the two most important (commonly used) are lj and aj / lj is basically the same as SQL LEFT JOIN @@ -669,7 +669,7 @@ aj[`time`sym;trades;quotes] / => 10:01:04 ge 150 / for each row in the trade table, the last (prevailing) quote (px) for that sym / is joined on. -/ see http://code.kx.com/wiki/JB:QforMortals2/queries_q_sql#Asof_Join +/ see http://code.kx.com/q4m3/9_Queries_q-sql/#998-as-of-joins //////////////////////////////////// ///// Extra/Advanced ////// @@ -716,7 +716,7 @@ first each (1 2 3;4 5 6;7 8 9) {x + y}/[1 2 3 4 5] / => 15 (only the final result) / There are other adverbs and uses, this is only intended as quick overview -/ http://code.kx.com/wiki/JB:QforMortals2/functions#Adverbs +/ http://code.kx.com/q4m3/6_Functions/#67-adverbs ////// Scripts ////// / q scripts can be loaded from a q session using the "\l" command @@ -756,7 +756,7 @@ select from splayed / (the columns are read from disk on request) / => 1 1 / => 2 2 / => 3 3 -/ see http://code.kx.com/wiki/JB:KdbplusForMortals/contents for more +/ see http://code.kx.com/q4m3/14_Introduction_to_Kdb+/ for more ////// Frameworks ////// / kdb+ is typically used for data capture and analysis. @@ -769,8 +769,8 @@ select from splayed / (the columns are read from disk on request) ## Want to know more? -* [*q for mortals* q language tutorial](http://code.kx.com/wiki/JB:QforMortals2/contents) -* [*kdb for mortals* on disk data tutorial](http://code.kx.com/wiki/JB:KdbplusForMortals/contents) -* [q language reference](http://code.kx.com/wiki/Reference) +* [*q for mortals* q language tutorial](http://code.kx.com/q4m3/) +* [*Introduction to Kdb+* on disk data tutorial](http://code.kx.com/q4m3/14_Introduction_to_Kdb+/) +* [q language reference](http://code.kx.com/q/ref/card/) * [Online training courses](http://training.aquaq.co.uk/) * [TorQ production framework](https://github.com/AquaQAnalytics/TorQ) diff --git a/lambda-calculus.html.markdown b/lambda-calculus.html.markdown new file mode 100644 index 00000000..6103c015 --- /dev/null +++ b/lambda-calculus.html.markdown @@ -0,0 +1,121 @@ +--- +category: Algorithms & Data Structures +name: Lambda Calculus +contributors: + - ["Max Sun", "http://github.com/maxsun"] +--- + +# Lambda Calculus + +Lambda calculus (λ-calculus), originally created by +[Alonzo Church](https://en.wikipedia.org/wiki/Alonzo_Church), +is the world's smallest programming language. +Despite not having numbers, strings, booleans, or any non-function datatype, +lambda calculus can be used to represent any Turing Machine! + +Lambda calculus is composed of 3 elements: **variables**, **functions**, and +**applications**. + + +| Name | Syntax | Example | Explanation | +|-------------|------------------------------------|-----------|-----------------------------------------------| +| Variable | `<name>` | `x` | a variable named "x" | +| Function | `λ<parameters>.<body>` | `λx.x` | a function with parameter "x" and body "x" | +| Application | `<function><variable or function>` | `(λx.x)a` | calling the function "λx.x" with argument "a" | + +The most basic function is the identity function: `λx.x` which is equivalent to +`f(x) = x`. The first "x" is the function's argument, and the second is the +body of the function. + +## Free vs. Bound Variables: + +- In the function `λx.x`, "x" is called a bound variable because it is both in +the body of the function and a parameter. +- In `λx.y`, "y" is called a free variable because it is never declared before hand. + +## Evaluation: + +Evaluation is done via +[β-Reduction](https://en.wikipedia.org/wiki/Lambda_calculus#Beta_reduction), +which is essentially lexically-scoped substitution. + +When evaluating the +expression `(λx.x)a`, we replace all occurences of "x" in the function's body +with "a". + +- `(λx.x)a` evaluates to: `a` +- `(λx.y)a` evaluates to: `y` + +You can even create higher-order functions: + +- `(λx.(λy.x))a` evaluates to: `λy.a` + +Although lambda calculus traditionally supports only single parameter +functions, we can create multi-parameter functions using a technique called +[currying](https://en.wikipedia.org/wiki/Currying). + +- `(λx.λy.λz.xyz)` is equivalent to `f(x, y, z) = x(y(z))` + +Sometimes `λxy.<body>` is used interchangeably with: `λx.λy.<body>` + +---- + +It's important to recognize that traditional **lambda calculus doesn't have +numbers, characters, or any non-function datatype!** + +## Boolean Logic: + +There is no "True" or "False" in lambda calculus. There isn't even a 1 or 0. + +Instead: + +`T` is represented by: `λx.λy.x` + +`F` is represented by: `λx.λy.y` + +First, we can define an "if" function `λbtf` that +returns `t` if `b` is True and `f` if `b` is False + +`IF` is equivalent to: `λb.λt.λf.b t f` + +Using `IF`, we can define the basic boolean logic operators: + +`a AND b` is equivalent to: `λab.IF a b F` + +`a OR b` is equivalent to: `λab.IF a T b` + +`a NOT b` is equivalent to: `λa.IF a F T` + +*Note: `IF a b c` is essentially saying: `IF(a(b(c)))`* + +## Numbers: + +Although there are no numbers in lambda calculus, we can encode numbers using +[Church numerals](https://en.wikipedia.org/wiki/Church_encoding). + +For any number n: <code>n = λf.f<sup>n</sup></code> so: + +`0 = λf.λx.x` + +`1 = λf.λx.f x` + +`2 = λf.λx.f(f x)` + +`3 = λf.λx.f(f(f x))` + +To increment a Church numeral, +we use the successor function `S(n) = n + 1` which is: + +`S = λn.λf.λx.f((n f) x)` + +Using successor, we can define add: + +`ADD = λab.(a S)n` + +**Challenge:** try defining your own multiplication function! + +## For more advanced reading: + +1. [A Tutorial Introduction to the Lambda Calculus](http://www.inf.fu-berlin.de/lehre/WS03/alpi/lambda.pdf) +2. [Cornell CS 312 Recitation 26: The Lambda Calculus](http://www.cs.cornell.edu/courses/cs3110/2008fa/recitations/rec26.html) +3. [Wikipedia - Lambda Calculus](https://en.wikipedia.org/wiki/Lambda_calculus)
\ No newline at end of file diff --git a/make.html.markdown b/make.html.markdown index ab128475..45d020e9 100644 --- a/make.html.markdown +++ b/make.html.markdown @@ -2,6 +2,7 @@ language: make
contributors:
- ["Robert Steed", "https://github.com/robochat"]
+ - ["Stephan Fuhrmann", "https://github.com/sfuhrm"]
filename: Makefile
---
@@ -11,7 +12,7 @@ target to the most recent version of the source. Famously written over a weekend by Stuart Feldman in 1976, it is still widely used (particularly
on Unix and Linux) despite many competitors and criticisms.
-There are many varieties of make in existence, however this article
+There are many varieties of make in existence, however this article
assumes that we are using GNU make which is the standard on Linux.
```make
@@ -168,9 +169,9 @@ echo: name2 = Sara # True within the matching rule # Some variables defined automatically by make.
echo_inbuilt:
echo $(CC)
- echo ${CXX)}
+ echo ${CXX}
echo $(FC)
- echo ${CFLAGS)}
+ echo ${CFLAGS}
echo $(CPPFLAGS)
echo ${CXXFLAGS}
echo $(LDFLAGS)
diff --git a/nim.html.markdown b/nim.html.markdown index 30dfa94f..1e17d8f0 100644 --- a/nim.html.markdown +++ b/nim.html.markdown @@ -15,15 +15,9 @@ Nim is efficient, expressive, and elegant. # Single-line comments start with a # #[ - Multi-line comments begin with a #[ - ... and end with ]# - -They don't care about indentation - - #[ - and they can be nested - ]# - + This is a multiline comment. + In Nim, multiline comments can be nested, beginning with #[ + ... and ending with ]# ]# discard """ diff --git a/nl-nl/html-nl.html.markdown b/nl-nl/html-nl.html.markdown new file mode 100644 index 00000000..54c81ed6 --- /dev/null +++ b/nl-nl/html-nl.html.markdown @@ -0,0 +1,98 @@ +--- +language: html +filename: learnhtml-nl.html +contributors: + - ["Christophe THOMAS", "https://github.com/WinChris"] +translators: + - ["Robert Steed", "https://github.com/robochat"] + - ["Jeroen Deviaene", "https://github.com/jerodev"] +lang: nl-nl +--- + +HTML staat voor HyperText Markup Language. +Het is een taal die je toe staat pagina's te maken op het World Wide Web. +Het is een opmaak taal, dit staat de gebruiker toe om webpagina's te maken in code en zo aan te duiden hoe de pagina moet weergegeven worden. +Eigenlijk zijn html files zelfs simpele tekst bestanden. +Wat is deze opmaak? Het is een manier om de structuur en data op de pagina weer te geven met speciale html tags. +Deze tags dienen om de betekenis te geven aan de tekst die het bevat. +Zoals vele computer talen heeft html vele verschillende versies. Hier zullen we HTML5 bespreken. + +**Merk op:** Je kan de verschillende tags en elementen testen terwijl je door de tutorial gaat met een website zoals [codepen](http://codepen.io/pen/), zo kan je de effecten hier van live zien. +Dit artikel gaat vooral over de HTML syntax en enkele handige tips + + +```html +<!-- Commentaren worden toegevoegd zoals deze lijn --> + +<!-- #################### De Tags #################### --> + +<!-- Hier is een voorbeeld HTML bestand dat we zullen analyseren. --> + +<!doctype html> + <html> + <head> + <title>Mijn Website</title> + </head> + <body> + <h1>Hello, world!</h1> + <a href="http://codepen.io/anon/pen/xwjLbZ">Neem een kijkje op deze link</a> + <p>Dit is een paragraaf.</p> + <p>Dit is nog een paragraaf.</p> + <ul> + <li>Dit is een item in een niet genummerde lijst</li> + <li>Dit is nog zo een item</li> + <li>En dit is het laatste item van de lijst</li> + </ul> + </body> + </html> + +<!-- Een HTML bestand start altijd met een tag die aan de browser laat weten dat we HTML gebruiken --> +<!doctype html> + +<!-- Daarna openen we de root van het bestand met de <html> tag --> +<html> + +<!-- Deze tag moet ook gesloten worden op het einde van het bestand --> +</html> + +<!-- Niets mag nog na deze tag komen! --> + +<!-- Binnenin (tussen de html tags <html></html>) vinden we: --> + +<!-- Een header, gedefigneerd door <head> (Deze moet gesloten worden met </head>) --> +<!-- De header bevat beschrijvingen en externe data die niet zichtbaar is op de website; Dit is metadata --> + +<head> + <title>Mijn Website</title><!-- De <title> tag geeft de tekst aan die in de titelbar van de browser moet weergegeven worden. --> +</head> + +<!-- Achter de <head> sectie vinden we bijna altijd <body> --> +<!-- Tot op dit punt is nog niets verschenen in het browser venster. --> +<!-- In de body plaatsen we wat zichtbaar moet zijn in de browser --> + +<body> + <h1>Hello, world!</h1> <!-- De h1 tag maakt een titel. --> + <!-- Er zijn ook sub titels voor <h1> van belangrijk <h2> tot minder belangrijk <h6>. --> + <a href="http://codepen.io/anon/pen/xwjLbZ">Neem een kijkje op deze link</a> <!-- een hyperlink naar de aangegeven link waar op geklikt kan worden in de browser --> + <p>This is a paragraph.</p> <!-- De tag <p> laat ons tekst toevoegen. --> + <p>This is another paragraph.</p> + <ul> <!-- De tag <ul> maakt een lijst met puntjes. --> + <!-- Om een genummerde lijst te hebben gebruik je <ol>, hiermee worden de elementen <li> automatisch genummerd --> + <li>This is an item in a non-enumerated list (bullet list)</li> + <li>This is another item</li> + <li>And this is the last item on the list</li> + </ul> +</body> + +<!-- En dat is het! Zo gemakkelijk is het om een html bestand te maken. --> +``` + +## Gebruik + +HTML wordt altijd opgeslagen in bestanden die eindigen in `.html`. + +## Meer weten + +* [wikipedia](https://nl.wikipedia.org/wiki/HTML) +* [HTML tutorial](https://developer.mozilla.org/en-US/docs/Web/HTML) +* [W3School](http://www.w3schools.com/html/html_intro.asp) diff --git a/ocaml.html.markdown b/ocaml.html.markdown index c087216c..74eb7993 100644 --- a/ocaml.html.markdown +++ b/ocaml.html.markdown @@ -375,4 +375,3 @@ sum_int_list t ;; * Visit the official website to get the compiler and read the docs: <http://ocaml.org/> * Try interactive tutorials and a web-based interpreter by OCaml Pro: <http://try.ocamlpro.com/> -* Read "OCaml for the skeptical" course: <http://www2.lib.uchicago.edu/keith/ocaml-class/home.html> diff --git a/pascal.html.markdown b/pascal.html.markdown new file mode 100644 index 00000000..6877afef --- /dev/null +++ b/pascal.html.markdown @@ -0,0 +1,96 @@ +--- +language: Pascal +filename: learnpascal.pas +contributors: + - ["Ganesha Danu", "http://github.com/blinfoldking"] +--- + + +>Pascal is an imperative and procedural programming language, which Niklaus Wirth designed in 1968–69 and published in 1970, as a small, efficient language intended to encourage good programming practices using structured programming and data structuring. It is named in honor of the French mathematician, philosopher and physicist Blaise Pascal. +source : [wikipedia](https://en.wikipedia.org/wiki/Pascal_(programming_language)) + + + +to compile and run a pascal program you could use a free pascal compiler. [Download Here](https://www.freepascal.org/) + +```pascal +//Anathomy of a Pascal Program +//this is a comment +{ + this is a + multiline comment +} + +//name of the program +program learn_pascal; //<-- dont forget a semicolon + +type + { + this is where you should delcare a custom + data-types + } +var + { + this is where you should declare a variable + } + +//main program area +begin + { + area to declare your instruction + } +end. // End of a main program area should required a "." symbol +``` + +```pascal +//declaring variable +//you can do this +var a:integer; +var b:integer; +//or this +var + a : integer; + b : integer; +//or this +var a,b : integer; +``` +```pascal +program Learn_More; +//Lets learn about data types and their operations + +//Declaring variables +var + int : integer; // a variable that contains an integer number data types + ch : char; // a variable that contains a character data types + str : string; // a variable that contains a string data types + r : real; // a variable that contains a real number data types + bool : boolean; //a variables that contains a Boolean(True/False) value data types +Begin + int := 1;// how to assign a value to a variable + r := 3.14; + ch := 'a'; + str := 'apple'; + bool := true; + //pascal is not a case-sensitive language + //arithmethic operation + int := 1 + 1; // int = 2 overwriting the previous assignment + int := int + 1; // int = 2 + 1 = 3; + int := 4 div 2; //int = 2 a division operation which the result will be floored + int := 3 div 2; //int = 1 + int := 1 div 2; //int = 0 + + bool := true or false; // bool = true + bool := false and true; // bool = false + bool := true xor true; // bool = false + + r := 3 / 2; // a division operator for real + r := int; // you can assign an integer to a real variable but not the otherwise + + c := str[1]; // assign the first letter of str to c + str := 'hello' + 'world'; //combining strings +End. +``` + +```pascal + +```
\ No newline at end of file diff --git a/php.html.markdown b/php.html.markdown index f82cea7d..d4fbaa32 100644 --- a/php.html.markdown +++ b/php.html.markdown @@ -841,7 +841,7 @@ try { try { // Do something -} catch (\Exception $e) { +} catch (Exception $e) { // Handle exception } diff --git a/prolog.html.markdown b/prolog.html.markdown index 7a18a144..f7b55ac6 100644 --- a/prolog.html.markdown +++ b/prolog.html.markdown @@ -38,9 +38,9 @@ magicNumber(42). % predicate names must start with lower case letters. We can now use % interactive mode to ask if it is true for different values: -?- magicNumber(7). % True -?- magicNumber(8). % False -?- magicNumber(9). % True +?- magicNumber(7). % True +?- magicNumber(8). % False +?- magicNumber(9). % True % Some older Prologs may display "Yes" and "No" instead of True and % False. @@ -50,7 +50,7 @@ magicNumber(42). % starting with a capital letter is a variable in Prolog. ?- magicNumber(Presto). % Presto = 7 ; - % Presto = 9 ; + % Presto = 9 ; % Presto = 42. % Prolog makes magicNumber true by assigning one of the valid numbers to @@ -66,26 +66,33 @@ magicNumber(42). % follows: % If both sides are bound (ie, defined), check equality. % If one side is free (ie, undefined), assign to match the other side. -% If both sides are free, abort because this can't be resolved. +% If both sides are free, the assignment is remembered. With some luck, +% one of the two sides will eventually be bound, but this isn't +% necessary. +% % The = sign in Prolog represents unification, so: ?- 2 = 3. % False - equality test -?- X = 3. % X = 3 - assignment -?- X = 2, X = Y. % X = Y = 2 - two assignments +?- X = 3. % X = 3 - assignment +?- X = 2, X = Y. % X = Y = 2 - two assignments % Note Y is assigned to, even though it is % on the right hand side, because it is free ?- X = 3, X = 2. % False - % First acts as assignment and binds X=3 - % Second acts as equality because X is bound + % First acts as assignment and binds X=3 + % Second acts as equality because X is bound % Since 3 does not equal 2, gives False % Thus in Prolog variables are immutable ?- X = 3+2. % X = 3+2 - unification can't do arithmetic ?- X is 3+2. % X = 5 - "is" does arithmetic. -?- 5 = X+2. % This is why = can't do arithmetic - +?- 5 = X+2. % This is why = can't do arithmetic - % because Prolog can't solve equations ?- 5 is X+2. % Error. Unlike =, the right hand side of IS % must always be bound, thus guaranteeing % no attempt to solve an equation. +?- X = Y, X = 2, Z is Y + 3. % X = Y, Y = 2, Z = 5. + % X = Y are both free, so Prolog remembers + % it. Therefore assigning X will also + % assign Y. % Any unification, and thus any predicate in Prolog, can either: % Succeed (return True) without changing anything, @@ -101,11 +108,11 @@ magicNumber(42). % example, Prolog has a built in predicate plus which represents % arithmetic addition but can reverse simple additions. -?- plus(1, 2, 3). % True +?- plus(1, 2, 3). % True ?- plus(1, 2, X). % X = 3 because 1+2 = X. -?- plus(1, X, 3). % X = 2 because 1+X = 3. -?- plus(X, 2, 3). % X = 1 because X+1 = 3. -?- plus(X, 5, Y). % Error - although this could be solved, +?- plus(1, X, 3). % X = 2 because 1+X = 3. +?- plus(X, 2, 3). % X = 1 because X+2 = 3. +?- plus(X, 5, Y). % Error - although this could be solved, % the number of solutions is infinite, % which most predicates try to avoid. @@ -129,9 +136,9 @@ magicNumber(42). ?- print("Hello"). % "Hello" true. ?- X = 2, print(X). % 2 true. -?- X = 2, print(X), X = 3. % 2 false - print happens immediately when - % it is encountered, even though the overall - % compound goal fails (because 2 != 3, +?- X = 2, print(X), X = 3. % 2 false - print happens immediately when + % it is encountered, even though the overall + % compound goal fails (because 2 != 3, % see the example above). % By using Print we can see what actually happens when we give a @@ -156,7 +163,7 @@ magicNumber(42). % the interactive prompt by pressing ;, for example: ?- magicNumber(X), print(X), X > 8. % 7 9 X = 9 ; - % 42 X = 42. + % 42 X = 42. % As you saw above we can define our own simple predicates as facts. % More complex predicates are defined as rules, like this: @@ -168,7 +175,7 @@ nearby(X,Y) :- Y is X-1. % nearby(X,Y) is true if Y is X plus or minus 1. % However this predicate could be improved. Here's why: -?- nearby(2,3). % True ; False. +?- nearby(2,3). % True ; False. % Because we have three possible definitions, Prolog sees this as 3 % possibilities. X = Y fails, so Y is X+1 is then tried and succeeds, % giving the True answer. But Prolog still remembers there are more @@ -177,11 +184,11 @@ nearby(X,Y) :- Y is X-1. % the option of rejecting the True answer, which doesn't make a whole % lot of sense. -?- nearby(4, X). % X = 4 ; - % X = 5 ; - % X = 3. Great, this works -?- nearby(X, 4). % X = 4 ; - % error +?- nearby(4, X). % X = 4 ; + % X = 5 ; + % X = 3. Great, this works +?- nearby(X, 4). % X = 4 ; + % error % After rejecting X = 4 prolog backtracks and tries "Y is X+1" which is % "4 is X+1" after substitution of parameters. But as we know from above % "is" requires its argument to be fully instantiated and it is not, so @@ -195,10 +202,10 @@ nearbychk(X,Y) :- Y is X+1, !. nearbychk(X,Y) :- Y is X-1. % This solves the first problem: -?- nearbychk(2,3). % True. +?- nearbychk(2,3). % True. % But unfortunately it has consequences: -?- nearbychk(2,X). % X = 2. +?- nearbychk(2,X). % X = 2. % Because Prolog cannot backtrack past the cut after X = Y, it cannot % try the possibilities "Y is X+1" and "Y is X-1", so it only generates % one solution when there should be 3. @@ -230,14 +237,14 @@ nearby3(X,Y) :- nearby2(X,Y). % Here is the structured comment declaration for nearby3: -%% nearby3(+X:Int, +Y:Int) is semidet. -%% nearby3(+X:Int, -Y:Int) is multi. -%% nearby3(-X:Int, +Y:Int) is multi. +%! nearby3(+X:Int, +Y:Int) is semideterministic. +%! nearby3(+X:Int, -Y:Int) is multi. +%! nearby3(-X:Int, +Y:Int) is multi. % For each variable we list a type. The + or - before the variable name % indicates if the parameter is bound (+) or free (-). The word after % "is" describes the behaviour of the predicate: -% semidet - can succeed once or fail +% semideterministic - can succeed once or fail % ( Two specific numbers are either nearby or not ) % multi - can succeed multiple times but cannot fail % ( One number surely has at least 3 nearby numbers ) @@ -250,13 +257,13 @@ nearby3(X,Y) :- nearby2(X,Y). % An unusual feature of Prolog is its support for atoms. Atoms are % essentially members of an enumerated type that are created on demand % whenever an unquoted non variable value is used. For example: -character(batman). % Creates atom value batman -character(robin). % Creates atom value robin -character(joker). % Creates atom value joker -character(darthVader). % Creates atom value darthVader -?- batman = batman. % True - Once created value is reused -?- batman = batMan. % False - atoms are case sensitive -?- batman = darthVader. % False - atoms are distinct +character(batman). % Creates atom value batman +character(robin). % Creates atom value robin +character(joker). % Creates atom value joker +character(darthVader). % Creates atom value darthVader +?- batman = batman. % True - Once created value is reused +?- batman = batMan. % False - atoms are case sensitive +?- batman = darthVader. % False - atoms are distinct % Atoms are popular in examples but were created on the assumption that % Prolog would be used interactively by end users - they are less @@ -267,54 +274,55 @@ character(darthVader). % Creates atom value darthVader % Note that below, writeln is used instead of print because print is % intended for debugging. -%% countTo(+X:Int) is det. -%% countUpTo(+Value:Int, +Limit:Int) is det. +%! countTo(+X:Int) is deterministic. +%! countUpTo(+Value:Int, +Limit:Int) is deterministic. countTo(X) :- countUpTo(1,X). countUpTo(Value, Limit) :- Value = Limit, writeln(Value), !. countUpTo(Value, Limit) :- Value \= Limit, writeln(Value), - NextValue is Value+1, - countUpTo(NextValue, Limit). + NextValue is Value+1, + countUpTo(NextValue, Limit). -?- countTo(10). % Outputs 1 to 10 +?- countTo(10). % Outputs 1 to 10 % Note the use of multiple declarations in countUpTo to create an % IF test. If Value = Limit fails the second declaration is run. % There is also a more elegant syntax. -%% countUpTo2(+Value:Int, +Limit:Int) is det. +%! countUpTo2(+Value:Int, +Limit:Int) is deterministic. countUpTo2(Value, Limit) :- writeln(Value), - Value = Limit -> true ; ( - NextValue is Value+1, - countUpTo2(NextValue, Limit)). + Value = Limit -> true ; ( + NextValue is Value+1, + countUpTo2(NextValue, Limit)). -?- countUpTo2(1,10). % Outputs 1 to 10 +?- countUpTo2(1,10). % Outputs 1 to 10 % If a predicate returns multiple times it is often useful to loop % through all the values it returns. Older Prologs used a hideous syntax % called a "failure-driven loop" to do this, but newer ones use a higher % order function. -%% countTo2(+X:Int) is det. +%! countTo2(+X:Int) is deterministic. countTo2(X) :- forall(between(1,X,Y),writeln(Y)). -?- countTo2(10). % Outputs 1 to 10 +?- countTo2(10). % Outputs 1 to 10 % Lists are given in square brackets. Use memberchk to check membership. % A group is safe if it doesn't include Joker or does include Batman. -%% safe(Group:list(atom)) is det. + +%! safe(Group:list(atom)) is deterministic. safe(Group) :- memberchk(joker, Group) -> memberchk(batman, Group) ; true. -?- safe([robin]). % True -?- safe([joker]). % False -?- safe([joker, batman]). % True +?- safe([robin]). % True +?- safe([joker]). % False +?- safe([joker, batman]). % True % The member predicate works like memberchk if both arguments are bound, % but can accept free variables and thus can be used to loop through % lists. -?- member(X, [1,2,3]). % X = 1 ; X = 2 ; X = 3 . +?- member(X, [1,2,3]). % X = 1 ; X = 2 ; X = 3 . ?- forall(member(X,[1,2,3]), - (Y is X+1, writeln(Y))). % 2 3 4 + (Y is X+1, writeln(Y))). % 2 3 4 % The maplist function can be used to generate lists based on other % lists. Note that the output list is a free variable, causing an diff --git a/pt-br/bf-pt.html.markdown b/pt-br/bf-pt.html.markdown index 52a5269e..c69995ab 100644 --- a/pt-br/bf-pt.html.markdown +++ b/pt-br/bf-pt.html.markdown @@ -1,5 +1,5 @@ --- -language: bf +language: Brainfuck filename: learnbf-pt.bf contributors: - ["Prajit Ramachandran", "http://prajitr.github.io/"] @@ -13,7 +13,9 @@ lang: pt-br Brainfuck (em letras minúsculas, exceto no início de frases) é uma linguagem de programação Turing-completa extremamente simples com apenas 8 comandos. -``` +Você pode experimentar brainfuck pelo seu browser com [brainfuck-visualizer](http://fatiherikli.github.io/brainfuck-visualizer/). + +```bf Qualquer caractere exceto "><+-.,[]" (sem contar as aspas) é ignorado. Brainfuck é representado por um vetor com 30 000 células inicializadas em zero diff --git a/pt-br/latex-pt.html.markdown b/pt-br/latex-pt.html.markdown new file mode 100644 index 00000000..a9ed566e --- /dev/null +++ b/pt-br/latex-pt.html.markdown @@ -0,0 +1,291 @@ +--- +language: latex +contributors: + - ["Chaitanya Krishna Ande", "http://icymist.github.io"] + - ["Colton Kohnke", "http://github.com/voltnor"] + - ["Sricharan Chiruvolu", "http://sricharan.xyz"] + - ["Ramanan Balakrishnan", "https://github.com/ramananbalakrishnan"] + - ["Svetlana Golubeva", "https://attillax.github.io/"] +translators: + - ["Paulo Henrique Rodrigues Pinheiro", "https://github.com/paulohrpinheiro"] +lang: pt-br +filename: learn-latex-pt.tex +--- + +```tex +% Todas as linhas de comentários começam com % +% Não existem comentários multilinhas + +$ LaTeX não é um programa processador de textos "Visual" como +% MS Word ou OpenOffice Writer + +$ Todo comando LaTeX começa com uma barra invertida (\) + +% Documentos LaTeX começam com a definição do tipo que será % compilado +% Os tipos de documento podem ser livro, relatório, apresentação, etc. +% As opções para um documento aparecem entre [] chaves. Nesse caso +% está especificado que queremos o tamanho da fonte em 12pt. +\documentclass[12pt]{article} + +% Em seguida definimos os pacotes que o documento usa. +% Se você quiser incluir gráficos, texto colorido, ou código fonte de outra +% linguagem em outro arquivo em seu documento, você precisa ampliar as +% capacidade do LaTeX. Isso é feito adicionando-se pacotes. +% Serão incluídos os pacotes float e caption para imagens e hyperref +% para links. +\usepackage{caption} +\usepackage{float} +\usepackage{hyperref} + +% Para poder usar caracteres acentuados, use o seguinte pacote: +\usepackage[utf8]{inputenc} + +% Podemos definir algumas outras propriedades do documento também! +\author{Chaitanya Krishna Ande, Colton Kohnke, Sricharan Chiruvolu \& \\ +Svetlana Golubeva} +\date{\today} +\title{Aprenda \LaTeX \hspace{1pt} em Y Minutos!} + +% Agora estamos pronto para começar o documento +% Tudo antes dessa linha é chamado "preâmbulo". +\begin{document} +% Se informarmos os campos author (autores), date (data), "title" (título), +% LaTeX poderá cria uma página inicial para nós. +\maketitle +% Se tivermos seções, poderemos criar uma tabela de conteúdo. Para isso, +% o documento deve ser compilado duas vezes, para que tudo apareça na ordem +% correta. +% É uma voa prática separar a tabela de conteúdo do corpo do documento. Para +% isso usa-se o comando \newpage +\newpage +\tableofcontents + +\newpage + +% Muitos artigos de pesquisa possuem um resumo, e pode-se isar comandos +% predefinidos para isso. +% Isso deve aparecer em sua ordem lógica, portanto, após o topo, +% mas antes das seções principais do corpo. +% Esse comando está disponível para os documentos do tipo artigo (article) +% e relatório (report). +\begin{abstract} + Documentação do \LaTeX \hspace{1pt} escrita em \LaTeX! Nada original! +\end{abstract} + +% Comandos para seções são intuitivos. +% Todos os títulos de seção são adicionados automaticamente à tabela de conteúdo. +\section{Introdução} +Olá, meu nome é Colton e juntos estamos explorando o mundo do \LaTeX! + +\section{Outra seção} +Esse é o texto para outra seção. Penso que precisamos de uma subseção. + +\subsection{Isso é uma subseção} % Subseções também são intuitivas. +Penso que precisamos de mais uma + +\subsubsection{Pythagoras} +Muito melhor agora. +\label{subsec:pythagoras} + +% Ao usar o asterisco nós impedimos a numeração automática. +% Isso funciona para outros comandos \LaTeX também. +\section*{Essa é uma seção não numerada} +Afinal nem todas as seções precisam ser numeradas! + +\section{Algumas notas sobre texto} +%\section{Espaçamento % É necessário mais informação sobre intervalos de espaço. +\LaTeX \hspace{1pt} geralmente é muito bom sobre colocar texto onde ele deve +ser posto. Se +uma linha \\ deve \\ ser \\ quebrada \\ adicione \textbackslash\textbackslash +\hspace{1pt} ao código de seu documento. \\ + +\section{Listas} +Listas são uma das coisas mais fáceis de criar no \LaTeX! Preciso fazer compras +amanhã, então façamos uma lista de compras. +\begin{enumerate} % Isso cria o bloco "enumerate". + % \item faz com que o enumerate incremente + \item Salada. + \item 27 melancias. + \item Uma lebre. + % pode-se também sobrescrever o número do item usando [] + \item[quantas?] Pistolas de água médias. + + Não é um item da lista, mas faz parte do bloco enumerate. + + \end{enumerate} % Todos os blocos devem ter um final (end{}). + +\section{Matemática} + +Um dos usos iniciais para \LaTeX \hspace{1pt} foi a produção de artigos +acadêmicos e técnicos. Usualmente nos campos da matemática e ciência. Assim, é +necessários que consigamos incluir alguns símbolos especiais em nosso texto! \\ + +A matemática tem muitos símbolos, além dos quais se pode encontrar no teclado; +símbolos para relações e conjuntos, setas, operadores, e letras gregas, apenas +para mencionar alguns.\\ + +Conjuntos e relações são essenciais em muitos textos de pesquisa em matemática. +Aqui está como você pode indicar como todo x que pertence +a X, $\forall$ x $\in$ X. \\ +% Perceba que é necessário adicionar os sinais $ antes e depois dos símbolos. +% Isso é porque quando escrevendo, estamos em modo texto. +% Mas os símbolos de matemática só existem no modo matemática. +% Podemos entrar no modo matemática a partir do modo texto com os símbolos $. +% O oposto também pode ocorrer. Variáveis podem ser renderizadas no modo +% matemática. +% Também podemos entrar no modo matemática com \[\] + +\[a^2 + b^2 = c^2 \] + +Minha letra grega favorita é $\xi$. Eu também gosto da $\beta$, $\gamma$ e $\sigma$. +Eu ainda não encontrei uma letra grega que o \LaTeX \hspace{1pt} não tenha!\\ + +Operadores são parte essencial de um documento sobre matemática: +funções trigonométricas ($\sin$, $\cos$, $\tan$), +logaritmo e exponencial ($\log$, $\exp$), +limites ($\lim$), etc. +possuem comandos pré-definidos em LaTex. +Vamos escrever uma equação para ver como se faz: +$\cos(2\theta) = \cos^{2}(\theta) - \sin^{2}(\theta)$ \\ + +Frações (numerador/denominador) podem ser escritas dessa forma: + +% 10 / 7 +$$ ^{10}/_{7} $$ + +% Frações relativamente complexas podem ser escritas como +% \frac{numerator}{denominator} +$$ \frac{n!}{k!(n - k)!} $$ \\ + +Também podemos escrever equações em um ``bloco de equação''. + +% Apresenta matemática com o 'bloco' equação +\begin{equation} % entra no modo matemática + c^2 = a^2 + b^2. + \label{eq:pythagoras} % para referência + \end{equation} % toda declaração \begin precisa de uma declaração end + +Podemos então referenciar nossa nova equação! +A equação~\ref{eq:pythagoras} é também conhecida como Teorema de Pitágoras que é +também assunto da Seção~\ref{subsec:pythagoras}. Muitas coisas podem ser +rotuladas: figuras, equações, seções, etc. + +Somatórios e Integrais são escritas com os comandos sum e int: + +% Alguns compiladores LaTeX irão reclamar se existirem linhas em branco +% em um bloco de equação. +\begin{equation} + \sum_{i=0}^{5} f_{i} +\end{equation} +\begin{equation} + \int_{0}^{\infty} \mathrm{e}^{-x} \mathrm{d}x +\end{equation} + +\section{Figuras} + +Insiramos uma Figura. O local para colocar a figura pode ser difícil +de determinar. Eu tenho sempre que verificar as opções toda vez. + +\begin{figure}[H] % H aqui é uma opção para o local da figura. + \centering % centra a figura na página + % Inclui uma figura com escala de 0.8 do tamanho da página. + %\includegraphics[width=0.8\linewidth]{right-triangle.png} + % Comentado para propósitos de compilação. Por favor, use sua imaginação. + \caption{Triângulo retângulo com lados $a$, $b$, $c$} + \label{fig:right-triangle} +\end{figure} + +\subsection{Tabelas} +Também podemos incluir tabelas da mesma forma que figuras. + +\begin{table}[H] + \caption{Título para a Tabela.} + % os argumentos {} abaixo descrevem como cada linha da tabela é desenhada. + % Aqui também, Preciso ver isso. Toda. E. Cada. Vez. + \begin{tabular}{c|cc} + Número & Sobrenome & Primeiro Nome \\ % Colunas são separadas por & + \hline % uma linha horizontal + 1 & Biggus & Dickus \\ + 2 & Monty & Python + \end{tabular} +\end{table} + +\section{Fazendo o \LaTeX \hspace{1pt} não compilar algo (o código fonte)} +Digamos que precisamos incluir algum código dentro do nosso +documento \LaTeX \hspace{1pt}, para isso precisamos com o \LaTeX \hspace{1pt} +não tente interpretar esse texto e que apenas inclua ele no documento. Fazemos +isso com o bloco verbatim. + +% Existem outros pacotes (por exemplo, minty, lstlisting, etc.) +% mas verbatim é o básico +\begin{verbatim} + print("Hello World!") + a%b; % olha só! Podemos usar os sinais % no bloco verbatim. + random = 4; #decided by fair random dice roll +\end{verbatim} + +\section{Compilando} + +Imagino que agora você esteja pensando como compilar esse fantástico documento +e visualizar a gloriosa glória que é um pdf gerado por \LaTeX \hspace{1pt} pdf. +(sim, esse documento é compilável). \\ + +Finalizando o documento usando \LaTeX \hspace{1pt} consiste nos seguintes passos: + \begin{enumerate} + \item Escrever o documento em texto puro (o ``código fonte''). + \item Compilar o código fonte para gerar um pdf. + Os passos para compilar se parecem (em Linux) com: \\ + \begin{verbatim} + > pdflatex learn-latex.tex + \end{verbatim} + \end{enumerate} + +Existem editores de \LaTeX \hspace{1pt} que combinam os passos 1 e 2 no mesmo +sistema de software. Assim, você pode ver o passo 1, mas não o passo 2 por +completo. Passo 2 estará acontecendo escondido\footnote{Por exemplo, quando usar +referências (como Equação~\ref{eq:pythagoras}), pode ser necessário executar o +passo 2 várias vezes, para gerar arquivos *.aux intermediários.}. +% É assim que você adiciona notas de rodapé em seus documentos! + +Você escreve toda a informação de formatação em texto puro, no passo 1. O +momento da compilação no passo 2 é responsável por produzir o documento no +formato que você definiu no passo 1. + +\section{Links} +Nós podemos inserir links em nosso documento. Para isso nós necessitamos incluir +o pacote hyperref no preâmbulo com o comando: +\begin{verbatim} + \usepackage{hyperref} +\end{verbatim} + +Existem dois tipos principais de links: URL visíveis \\ +\url{https://learnxinyminutes.com/docs/latex/}, ou +\href{https://learnxinyminutes.com/docs/latex/}{um texto alternativo} +% Você não pode adicionar espaços extras ou símbolos especiais no texto +% alternativo, pois isso causará problemas na compilação. + +Esse pacote também produz uma lista de thumbnails no documento pdf gerado e +ativa os links na tabela de conteúdo. + +\section{End} + +Por enquanto é isso! + +% Frequentemente você precisa de uma seção de referências em seu documento. +% A forma mais fácil de configurá-la é usando uma seção de bibliografia +\begin{thebibliography}{1} + % como em outras listas, o comando \bibitem pode ser usado para itens da lista + % cada entrada pode ser citada diretamente no corpo do texto + \bibitem{latexwiki} The amazing \LaTeX \hspace{1pt} wikibook: {\em +https://en.wikibooks.org/wiki/LaTeX} + \bibitem{latextutorial} An actual tutorial: {\em http://www.latex-tutorial.com} +\end{thebibliography} + +% end the document +\end{document} +``` + +## Mais sobre LaTeX + +* The amazing LaTeX wikibook: [https://en.wikibooks.org/wiki/LaTeX](https://en.wikibooks.org/wiki/LaTeX) +* An actual tutorial: [http://www.latex-tutorial.com/](http://www.latex-tutorial.com/) diff --git a/python3.html.markdown b/python3.html.markdown index 864228e4..b0f04a02 100644 --- a/python3.html.markdown +++ b/python3.html.markdown @@ -210,9 +210,9 @@ li[4] # Raises an IndexError # The start index is included, the end index is not # (It's a closed/open range for you mathy types.) li[1:3] # => [2, 4] -# Omit the end +# Omit the beginning and return the list li[2:] # => [4, 3] -# Omit the beginning +# Omit the end and return the list li[:3] # => [1, 2, 4] # Select every second entry li[::2] # =>[1, 4] diff --git a/pythonstatcomp.html.markdown b/pythonstatcomp.html.markdown index 79bbcd8d..6dde1cf0 100644 --- a/pythonstatcomp.html.markdown +++ b/pythonstatcomp.html.markdown @@ -13,10 +13,11 @@ This is a tutorial on how to do some typical statistical programming tasks using # 0. Getting set up ==== -""" Get set up with IPython and pip install the following: numpy, scipy, pandas, +""" To get started, pip install the following: jupyter, numpy, scipy, pandas, matplotlib, seaborn, requests. - Make sure to do this tutorial in the IPython notebook so that you get - the inline plots and easy documentation lookup. + Make sure to do this tutorial in a Jupyter notebook so that you get + the inline plots and easy documentation lookup. The shell command to open + one is simply `jupyter notebook`, then click New -> Python. """ # 1. Data acquisition ==== diff --git a/scala.html.markdown b/scala.html.markdown index 78053b40..016e2b4f 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -276,6 +276,8 @@ r foreach println // NB: Scala is quite lenient when it comes to dots and brackets - study the // rules separately. This helps write DSLs and APIs that read like English +// Why doesn't `println` need any parameters here? +// Stay tuned for first-class functions in the Functional Programming section below! (5 to 1 by -1) foreach (println) // A while loop @@ -299,7 +301,7 @@ do { // Recursion is the idiomatic way of repeating an action in Scala (as in most // other functional languages). // Recursive functions need an explicit return type, the compiler can't infer it. -// Here it's Unit. +// Here it's Unit, which is analagous to a `void` return type in Java def showNumbersInRange(a: Int, b: Int): Unit = { print(a) if (a < b) @@ -412,8 +414,8 @@ class Dog(br: String) { private def sleep(hours: Int) = println(s"I'm sleeping for $hours hours") - // Abstract methods are simply methods with no body. If we uncomment the next - // line, class Dog would need to be declared abstract + // Abstract methods are simply methods with no body. If we uncomment the + // def line below, class Dog would need to be declared abstract like so: // abstract class Dog(...) { ... } // def chaseAfter(what: String): String } @@ -455,7 +457,7 @@ george.phoneNumber // => "1234" Person("George", "1234") == Person("Kate", "1236") // => false // Easy way to copy -// otherGeorge == Person("george", "9876") +// otherGeorge == Person("George", "9876") val otherGeorge = george.copy(phoneNumber = "9876") // And many others. Case classes also get pattern matching for free, see below. @@ -523,7 +525,9 @@ def matchPerson(person: Person): String = person match { case Person(name, number) => "We matched someone : " + name + ", phone : " + number } -val email = "(.*)@(.*)".r // Define a regex for the next example. +// Regular expressions are also built in. +// Create a regex with the `r` method on a string: +val email = "(.*)@(.*)".r // Pattern matching might look familiar to the switch statements in the C family // of languages, but this is much more powerful. In Scala, you can match much @@ -589,6 +593,8 @@ List("Dom", "Bob", "Natalia") foreach println // Combinators +// Using `s` from above: +// val s = Set(1, 3, 7) s.map(sq) @@ -608,8 +614,8 @@ List( ).filter(_.age > 25) // List(Person("Bob", 30)) -// Scala a foreach method defined on certain collections that takes a type -// returning Unit (a void method) +// Certain collections (such as List) in Scala have a `foreach` method, +// which takes as an argument a type returning Unit - that is, a void method val aListOfNumbers = List(1, 2, 3, 4, 10, 20, 100) aListOfNumbers foreach (x => println(x)) aListOfNumbers foreach println diff --git a/solidity.html.markdown b/solidity.html.markdown index 0b2f5f67..a0f8cd40 100644 --- a/solidity.html.markdown +++ b/solidity.html.markdown @@ -37,8 +37,8 @@ features are typically marked, and subject to change. Pull requests welcome. // simple_bank.sol (note .sol extension) /* **** START EXAMPLE **** */ -// Declare the source file compiler version. -pragma solidity ^0.4.2; +// Declare the source file compiler version +pragma solidity ^0.4.19; // Start with Natspec comment (the three slashes) // used for documentation - and as descriptive data for UI elements/actions @@ -65,7 +65,7 @@ contract SimpleBank { // CapWords event LogDepositMade(address accountAddress, uint amount); // Constructor, can receive one or many variables here; only one allowed - function SimpleBank() { + function SimpleBank() public { // msg provides details about the message that's sent to the contract // msg.sender is contract caller (address of contract creator) owner = msg.sender; @@ -73,7 +73,11 @@ contract SimpleBank { // CapWords /// @notice Deposit ether into bank /// @return The balance of the user after the deposit is made - function deposit() public returns (uint) { + function deposit() public payable returns (uint) { + // Use 'require' to test user inputs, 'assert' for internal invariants + // Here we are making sure that there isn't an overflow issue + require((balances[msg.sender] + msg.value) >= balances[msg.sender]); + balances[msg.sender] += msg.value; // no "this." or "self." required with state variable // all values set to data type's initial value by default @@ -88,18 +92,17 @@ contract SimpleBank { // CapWords /// @param withdrawAmount amount you want to withdraw /// @return The balance remaining for the user function withdraw(uint withdrawAmount) public returns (uint remainingBal) { - if(balances[msg.sender] >= withdrawAmount) { - // Note the way we deduct the balance right away, before sending - due to - // the risk of a recursive call that allows the caller to request an amount greater - // than their balance - balances[msg.sender] -= withdrawAmount; - - if (!msg.sender.send(withdrawAmount)) { - // increment back only on fail, as may be sending to contract that - // has overridden 'send' on the receipt end - balances[msg.sender] += withdrawAmount; - } - } + require(withdrawAmount <= balances[msg.sender]); + + // Note the way we deduct the balance right away, before sending + // Every .transfer/.send from this contract can call an external function + // This may allow the caller to request an amount greater + // than their balance using a recursive call + // Aim to commit state before calling external functions, including .transfer/.send + balances[msg.sender] -= withdrawAmount; + + // this automatically throws on a failure, which means the updated balance is reverted + msg.sender.transfer(withdrawAmount); return balances[msg.sender]; } @@ -108,18 +111,9 @@ contract SimpleBank { // CapWords /// @return The balance of the user // 'constant' prevents function from editing state variables; // allows function to run locally/off blockchain - function balance() constant returns (uint) { + function balance() constant public returns (uint) { return balances[msg.sender]; } - - // Fallback function - Called if other functions don't match call or - // sent ether without data - // Typically, called when invalid data is sent - // Added so ether sent to this contract is reverted if the contract fails - // otherwise, the sender's money is transferred to contract - function () { - throw; // throw reverts state to before call - } } // ** END EXAMPLE ** @@ -137,6 +131,11 @@ int256 constant a = 8; // same effect as line above, here the 256 is explicit uint constant VERSION_ID = 0x123A1; // A hex constant // with 'constant', compiler replaces each occurrence with actual value +// All state variables (those outside a function) +// are by default 'internal' and accessible inside contract +// and in all contracts that inherit ONLY +// Need to explicitly set to 'public' to allow external contracts to access +int256 public a = 8; // For int and uint, can explicitly set space in steps of 8 up to 256 // e.g., int8, int16, int24 @@ -145,6 +144,12 @@ int64 c; uint248 e; // Be careful that you don't overflow, and protect against attacks that do +// For example, for an addition, you'd do: +uint256 c = a + b; +assert(c >= a); // assert tests for internal invariants; require is used for user inputs +// For more examples of common arithmetic issues, see Zeppelin's SafeMath library +// https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/math/SafeMath.sol + // No random functions built in, use other contracts for randomness @@ -165,14 +170,14 @@ address public owner; // a getter is automatically created, but NOT a setter // All addresses can be sent ether -owner.send(SOME_BALANCE); // returns false on failure -if (owner.send) {} // REMEMBER: wrap in 'if', as contract addresses have +owner.transfer(SOME_BALANCE); // fails and reverts on failure + +// Can also do a lower level .send call, which returns a false if it failed +if (owner.send) {} // REMEMBER: wrap send in 'if', as contract addresses have // functions executed on send and these can fail // Also, make sure to deduct balances BEFORE attempting a send, as there is a risk of a recursive // call that can drain the contract -// can override send by defining your own - // Can check balance owner.balance; // the balance of the owner (user or contract) @@ -213,7 +218,7 @@ uint x = 5; // Destructuring/Tuples -(x, y) = (2, 7); // assign/swap multiple value +(x, y) = (2, 7); // assign/swap multiple values // 2. DATA STRUCTURES @@ -250,7 +255,7 @@ delete balances; // sets all elements to 0 // mapping, without knowing source keys - can build data structure // on top to do this -// Structs and enums +// Structs struct Bank { address owner; uint balance; @@ -273,7 +278,7 @@ state = State.Created; // enums can be explicitly converted to ints uint createdState = uint(State.Created); // 0 -// Data locations: Memory vs. storage vs. stack - all complex types (arrays, +// Data locations: Memory vs. storage vs. calldata - all complex types (arrays, // structs) have a data location // 'memory' does not persist, 'storage' does // Default is 'storage' for local and state variables; 'memory' for func params @@ -292,13 +297,13 @@ uint createdState = uint(State.Created); // 0 // 4. Global Variables of note // ** this ** this; // address of contract -// often used at end of contract life to send remaining balance to party +// often used at end of contract life to transfer remaining balance to party this.balance; this.someFunction(); // calls func externally via call, not via internal jump // ** msg - Current message received by the contract ** ** msg.sender; // address of sender -msg.value; // amount of ether provided to this contract in wei +msg.value; // amount of ether provided to this contract in wei, the function should be marked "payable" msg.data; // bytes, complete call data msg.gas; // remaining gas @@ -308,6 +313,8 @@ tx.gasprice; // gas price of the transaction // ** block - Information about current block ** now; // current time (approximately), alias for block.timestamp (uses Unix time) +// Note that this can be manipulated by miners, so use carefully + block.number; // current block number block.difficulty; // current block difficulty block.blockhash(1); // returns bytes32, only works for most recent 256 blocks @@ -334,9 +341,10 @@ function increment(uint x, uint y) returns (uint x, uint y) { // Call previous functon uint (a,b) = increment(1,1); -// 'constant' indicates that function does not/cannot change persistent vars +// 'constant' (alias for 'view') +// indicates that function does not/cannot change persistent vars // Constant function execute locally, not on blockchain -uint y; +uint y = 1; function increment(uint x) constant returns (uint x) { x += 1; @@ -344,13 +352,21 @@ function increment(uint x) constant returns (uint x) { // y is a state variable, and can't be changed in a constant function } +// 'pure' is more strict than 'constant', and does not +// even allow reading of state vars +// The exact rules are more complicated, so see more about +// constant/pure: +// http://solidity.readthedocs.io/en/develop/contracts.html#view-functions + // 'Function Visibility specifiers' // These can be placed where 'constant' is, including: -// public - visible externally and internally (default) -// external +// public - visible externally and internally (default for function) +// external - only visible externally (including a call made with this.) // private - only visible in the current contract // internal - only visible in current contract, and those deriving from it +// Generally, a good idea to mark each function explicitly + // Functions hoisted - and can assign a function to a variable function a() { var z = b; @@ -361,8 +377,15 @@ function b() { } +// All functions that receive ether must be marked 'payable' +function depositEther() public payable { + balances[msg.sender] += msg.value; +} + // Prefer loops to recursion (max call stack depth is 1024) +// Also, don't setup loops that you haven't bounded, +// as this can hit the gas limit // B. Events // Events are notify external parties; easy to search and @@ -378,7 +401,8 @@ event LogSent(address indexed from, address indexed to, uint amount); // note ca // Call Sent(from, to, amount); -// For an external party (a contract or external entity), to watch: +// For an external party (a contract or external entity), to watch using +// the Web3 Javascript library: Coin.Sent().watch({}, '', function(error, result) { if (!error) { console.log("Coin transfer: " + result.args.amount + @@ -398,10 +422,10 @@ Coin.Sent().watch({}, '', function(error, result) { // '_' (underscore) often included as last line in body, and indicates // function being called should be placed there -modifier onlyAfter(uint _time) { if (now <= _time) throw; _ } -modifier onlyOwner { if (msg.sender == owner) _ } +modifier onlyAfter(uint _time) { require (now >= _time); _; } +modifier onlyOwner { require(msg.sender == owner) _; } // commonly used with state machines -modifier onlyIfState (State currState) { if (currState != State.A) _ } +modifier onlyIfStateA (State currState) { require(currState == State.A) _; } // Append right after function declaration function changeOwner(newOwner) @@ -415,12 +439,10 @@ onlyIfState(State.A) // underscore can be included before end of body, // but explicitly returning will skip, so use carefully modifier checkValue(uint amount) { - _ + _; if (msg.value > amount) { uint amountToRefund = amount - msg.value; - if (!msg.sender.send(amountToRefund)) { - throw; - } + msg.sender.transfer(amountToRefund); } } @@ -437,22 +459,21 @@ modifier checkValue(uint amount) { // amount of gas for a block of code - and will fail if that is exceeded // For example: for(uint x = 0; x < refundAddressList.length; x++) { - if (!refundAddressList[x].send(SOME_AMOUNT)) { - throw; - } + refundAddressList[x].transfer(SOME_AMOUNT); } // Two errors above: -// 1. A failure on send stops the loop from completing, tying up money +// 1. A failure on transfer stops the loop from completing, tying up money // 2. This loop could be arbitrarily long (based on the amount of users who need refunds), and // therefore may always fail as it exceeds the max gas for a block // Instead, you should let people withdraw individually from their subaccount, and mark withdrawn +// e.g., favor pull payments over push payments // 7. OBJECTS/CONTRACTS // A. Calling external contract -contract infoFeed { +contract InfoFeed { function info() returns (uint ret) { return 42; } } @@ -502,23 +523,10 @@ function someAbstractFunction(uint x); import "filename"; import "github.com/ethereum/dapp-bin/library/iterable_mapping.sol"; -// Importing under active development -// Cannot currently be done at command line - // 8. OTHER KEYWORDS -// A. Throwing -// Throwing -throw; // reverts unused money to sender, state is reverted -// Can't currently catch - -// Common design pattern is: -if (!addr.send(123)) { - throw; -} - -// B. Selfdestruct +// A. Selfdestruct // selfdestruct current contract, sending funds to address (often creator) selfdestruct(SOME_ADDRESS); @@ -543,7 +551,7 @@ function remove() { // that is private needs to be obfuscated (e.g., hashed w/secret) // Steps: 1. Commit to something, 2. Reveal commitment -sha3("some_bid_amount", "some secret"); // commit +keccak256("some_bid_amount", "some secret"); // commit // call contract's reveal function in the future // showing bid plus secret that hashes to SHA3 @@ -617,6 +625,7 @@ contract SomeOracle { // ** START EXAMPLE ** // CrowdFunder.sol +pragma solidity ^0.4.19; /// @title CrowdFunder /// @author nemild @@ -650,22 +659,20 @@ contract CrowdFunder { event LogWinnerPaid(address winnerAddress); modifier inState(State _state) { - if (state != _state) throw; - _ + require(state == _state); + _; } modifier isCreator() { - if (msg.sender != creator) throw; - _ + require(msg.sender == creator); + _; } - // Wait 6 months after final contract state before allowing contract destruction + // Wait 24 weeks after final contract state before allowing contract destruction modifier atEndOfLifecycle() { - if(!((state == State.ExpiredRefund || state == State.Successful) && - completeAt + 6 months < now)) { - throw; - } - _ + require(((state == State.ExpiredRefund || state == State.Successful) && + completeAt + 24 weeks < now)); + _; } function CrowdFunder( @@ -673,6 +680,7 @@ contract CrowdFunder { string _campaignUrl, address _fundRecipient, uint _minimumToRaise) + public { creator = msg.sender; fundRecipient = _fundRecipient; @@ -683,7 +691,9 @@ contract CrowdFunder { function contribute() public + payable inState(State.Fundraising) + returns(uint256 id) { contributions.push( Contribution({ @@ -699,7 +709,9 @@ contract CrowdFunder { return contributions.length - 1; // return id } - function checkIfFundingCompleteOrExpired() { + function checkIfFundingCompleteOrExpired() + public + { if (totalRaised > minimumToRaise) { state = State.Successful; payOut(); @@ -715,31 +727,23 @@ contract CrowdFunder { public inState(State.Successful) { - if(!fundRecipient.send(this.balance)) { - throw; - } - - + fundRecipient.transfer(this.balance); LogWinnerPaid(fundRecipient); } - function getRefund(id) - public + function getRefund(uint256 id) inState(State.ExpiredRefund) + public + returns(bool) { - if (contributions.length <= id || id < 0 || contributions[id].amount == 0 ) { - throw; - } + require(contributions.length > id && id >= 0 && contributions[id].amount != 0 ); - uint amountToRefund = contributions[id].amount; + uint256 amountToRefund = contributions[id].amount; contributions[id].amount = 0; - if(!contributions[id].contributor.send(amountToSend)) { - contributions[id].amount = amountToSend; - return false; - } + contributions[id].contributor.transfer(amountToRefund); - return true; + return true; } function removeContract() @@ -750,8 +754,6 @@ contract CrowdFunder { selfdestruct(msg.sender); // creator gets all money that hasn't be claimed } - - function () { throw; } } // ** END EXAMPLE ** @@ -798,6 +800,7 @@ someContractAddress.callcode('function_name'); // 13. STYLE NOTES // Based on Python's PEP8 style guide +// Full Style guide: http://solidity.readthedocs.io/en/develop/style-guide.html // Quick summary: // 4 spaces for indentation @@ -825,12 +828,16 @@ someContractAddress.callcode('function_name'); ## Additional resources - [Solidity Docs](https://solidity.readthedocs.org/en/latest/) +- [Smart Contract Best Practices](https://github.com/ConsenSys/smart-contract-best-practices) - [Solidity Style Guide](https://ethereum.github.io/solidity//docs/style-guide/): Ethereum's style guide is heavily derived from Python's [pep8](https://www.python.org/dev/peps/pep-0008/) style guide. - [EthFiddle - The JsFiddle for Solidity](https://ethfiddle.com/) -- [Browser-based Solidity Editor](http://chriseth.github.io/browser-solidity/) +- [Browser-based Solidity Editor](https://remix.ethereum.org/) - [Gitter Solidity Chat room](https://gitter.im/ethereum/solidity) - [Modular design strategies for Ethereum Contracts](https://docs.erisindustries.com/tutorials/solidity/) +## Important libraries +- [Zeppelin](https://github.com/OpenZeppelin/zeppelin-solidity/): Libraries that provide common contract patterns (crowdfuding, safemath, etc) + ## Sample contracts - [Dapp Bin](https://github.com/ethereum/dapp-bin) - [Solidity Baby Step Contracts](https://github.com/fivedogit/solidity-baby-steps/tree/master/contracts) @@ -842,9 +849,6 @@ someContractAddress.callcode('function_name'); - [Smart Contract Security](https://blog.ethereum.org/2016/06/10/smart-contract-security/) - [Hacking Distributed Blog](http://hackingdistributed.com/) -## Information purposefully excluded -- Libraries - ## Style - Python's [PEP8](https://www.python.org/dev/peps/pep-0008/) is used as the baseline style guide, including its general philosophy diff --git a/standard-ml.html.markdown b/standard-ml.html.markdown index 5db15b5c..b34f1c08 100644 --- a/standard-ml.html.markdown +++ b/standard-ml.html.markdown @@ -6,6 +6,7 @@ contributors: - ["David Pedersen", "http://lonelyproton.com/"] - ["James Baker", "http://www.jbaker.io/"] - ["Leo Zovic", "http://langnostic.inaimathi.ca/"] + - ["Chris Wilson", "http://sencjw.com/"] --- Standard ML is a functional programming language with type inference and some @@ -266,6 +267,16 @@ fun second_elem (x::y::xs) = y fun evenly_positioned_elems (odd::even::xs) = even::evenly_positioned_elems xs | evenly_positioned_elems [odd] = [] (* Base case: throw away *) | evenly_positioned_elems [] = [] (* Base case *) + +(* The case expression can also be used to pattern match and return a value *) +datatype temp = + C of real + | F of real + +fun temp_to_f t = + case t of + C x => x * (9.0 / 5.0) + 32.0 + | F x => x (* When matching on records, you must use their slot names, and you must bind every slot in a record. The order of the slots doesn't matter though. *) diff --git a/sv-se/haskell-sv.html.markdown b/sv-se/haskell-sv.html.markdown new file mode 100644 index 00000000..da2d6ab0 --- /dev/null +++ b/sv-se/haskell-sv.html.markdown @@ -0,0 +1,461 @@ +--- +language: Haskell +filename: learnhaskell-sv.hs +contributors: + - ["Adit Bhargava", "http://adit.io"] +translators: + - ["Edward Tjörnhammar", "http://edwtjo.me"] +lang: sv-se +--- + +Haskell skapades för att vara ett praktiskt, rent, funktionellt +programmeringsspråk. Det är känt för sin använding av monader och dess +härledande typsystem men anledningen till att jag ständigt återbesöker språket +är på grund av dess elegans. Haskell gör programmering till ett rent nöje. + +```haskell +-- Radkommenterar börjar med två bindestreck. +{- Flerradskommentarer innesluts av vänster/höger måsvinge bindestreck +block på detta vis. +-} + +---------------------------------------------------- +-- 1. Fördefinierade datatyper och operatorer +---------------------------------------------------- + +-- Du har siffror +3 -- 3 + +-- Matte fungerar som förväntat +1 + 1 -- 2 +8 - 1 -- 7 +10 * 2 -- 20 +35 / 5 -- 7.0 + +-- Division är normalt inte heltalsdivision +35 / 4 -- 8.75 + +-- Heltalsdivision, här infix div +35 `div` 4 -- 8 + +-- Boolar (Sant och Falskt) är fördefinierade +True +False + +-- Samt dess operationer +not True -- False +not False -- True +1 == 1 -- True +1 /= 1 -- False +1 < 10 -- True + +-- I ovanstående exempel är `not` en funktion vilken bara tar ett argument. +-- Haskell behöver inte paranteser för sina funktionsanrop... alla argument +-- ges mellanslagsseparerade direkt efter funktionen. Det övergripande mönstret +-- är: +-- func arg1 arg2 arg3... +-- Se sektionen om funktioner för information om hur du skriver dina egna. + +-- Strängar och bokstäver +"Detta är en sträng" +'a' -- bokstav +'Du kan inte använda enkelfnutt för strängar.' -- fel! + +-- Strängar kan konkateneras +"Hej " ++ "världen!" -- "Hej världen!" + +-- En sträng är en lista av bokstäver +['H', 'e', 'j', 's', 'a', 'n'] -- "Hejsan" +"Detta är en sträng" !! 0 -- 'D' + + +---------------------------------------------------- +-- 2. Listor och Tupler +---------------------------------------------------- + +-- Varje element i en lista måste ha samma typ. +-- Dessa listor är ekvivalenta: +[1, 2, 3, 4, 5] +[1..5] + +-- Intervall är mångsidiga. +['A'..'F'] -- "ABCDEF" + +-- Man kan stega intervall. +[0,2..10] -- [0, 2, 4, 6, 8, 10] +[5..1] -- [] (Haskell förutsätter normalt inkrement) +[5,4..1] -- [5, 4, 3, 2, 1] + +-- Indexering in i en lista +[1..10] !! 3 -- 4 (nollindexerat) + +-- Man kan ha oändliga listor i Haskell! +[1..] -- listan över alla naturliga tal + +-- Oändliga listor fungerar enbart för att Haskell har "lat evaluering". +-- Det betyder att Haskell bara evaluerar de uttryck den måste. Du kan alltså +-- fråga efter det 1000:e elementet i en oändlig lista och Haskell kommer då ge +-- dig det: + +[1..] !! 999 -- 1000 + +-- Nu har Haskell evaluerat element 1 till 1000 i denna lista... men resten +-- av medlemmarna i denna oändliga lista existerar inte ännu! Haskell kommer +-- faktiskt inte utvärdera element den inte måste. + +-- Sammanslagning av två listor +[1..5] ++ [6..10] + +-- Lägg till 0 vid listhuvudet +0:[1..5] -- [0, 1, 2, 3, 4, 5] + +-- fler listoperationer som huvud, svans, initiella samt sista +head [1..5] -- 1 +tail [1..5] -- [2, 3, 4, 5] +init [1..5] -- [1, 2, 3, 4] +last [1..5] -- 5 + +-- listomfattningar +[x*2 | x <- [1..5]] -- [2, 4, 6, 8, 10] + +-- med bivilkor +[x*2 | x <- [1..5], x*2 > 4] -- [6, 8, 10] + +-- Varje element i en tupel kan ha olika typ men en tupel kan bara ha en +-- fixerad, eller statisk, längd. +-- En tupel: +("haskell", 1) + +-- För att komma åt element i ett par, alltså en 2-tupel, finns +-- de fördefinierade funktionerna: +fst ("haskell", 1) -- "haskell" +snd ("haskell", 1) -- 1 + +---------------------------------------------------- +-- 3. Funktioner +---------------------------------------------------- +-- En enkel funktion med två parametrar +add a b = a + b + +-- Notera även att om du använder ghci (Haskellinterpretatorn) kommer du behöva +-- använda `let` namnbindning för att synliggöra din funktionsdeklaration, +-- alltså +let add a b = a + b + +-- För att använda funktionen +add 1 2 -- 3 + +-- Man kan även göra funktionsanropet infix, alltså mellan parametersättningen, +-- med hjälp av bakåtfnuttar: +1 `add` 2 -- 3 + +-- Du kan även definiera funktioner vars funktionsnamn avsaknar bokstäver! +-- Med hjälp av parenteser kan du därmed definiera operatorer (normalt infix)! +-- Följande är en operator för heltalsdivision, vilken förlitar sig på div: +(//) a b = a `div` b +35 // 4 -- 8 + +-- Funktionsvakter: ett enkelt sätt att grena ut dina funktioner +fib x + | x < 2 = 1 + | otherwise = fib (x - 1) + fib (x - 2) + +-- Mönstermatchning fungerar på liknande vis. Här ger vi tre olika +-- parametermatchningar för vårat fib-resulat. Haskell kommer automatiskt följa +-- första bästa träff, uppifrån ned, vars vänstra sida om likhetstecknet matchar +-- anroparens parametervärde. +fib 1 = 1 +fib 2 = 2 +fib x = fib (x - 1) + fib (x - 2) + +-- Mönstermatchning på tupler: +foo (x, y) = (x + 1, y + 2) + +-- Mönstermatchning på listor. Här är `x` det första elementet i listan och `xs` +-- är resten av listan. Nu kan vi skriva våran egen map-funktion +minMap func [] = [] +minMap func (x:xs) = func x:(minMap func xs) + +-- Anonyma funktioner, eller lambdauttryck, skapas med hjälp av omvänt +-- snedstreck, följt av parametrarna +minMap (\x -> x + 2) [1..5] -- [3, 4, 5, 6, 7] + +-- Användning av fold (även kallad `inject`, `reduce`, osv.) tillsammans med en +-- anonym funktion. `fold1` är en vänstervikande funktion och använder första +-- värdet i listan som det initiella värdet för ackumulatorn. +foldl1 (\acc x -> acc + x) [1..5] -- 15 + +---------------------------------------------------- +-- 4. Mer funktioner +---------------------------------------------------- + +-- Partiell applikation: +-- Om du inte anropar funktionen med alla sina argument +-- blir den partiellt applicerad. Det betyder att du erhåller en funktion där en +-- delmängd av parametrarna blivit värdesatta men några är fortfarande fria. +add a b = a + b +foo = add 10 -- foo är nu en funktion som tar ett nummer och lägger till 10 till + -- det +foo 5 -- 15 + +-- Ett annat sätt att skriva samma sak +foo = (10+) +foo 5 -- 15 + +-- Funktionskomposition: +-- Operatorn `.` kedjar ihop funktioner +-- Till exempel, nedan är `foo` en funktion som tar ett värde, den adderar 10 +-- till det, multiplicerar det resultatet med 4 och sen ersätts med det värdet. +foo = (4*) . (10+) + +-- 4*(10+5) = 60 +foo 5 -- 60 + +-- Precedensordning: +-- Haskell har en operator `$`. Denna operator applicerar en funktion till en +-- given parameter med dess precedens. I kontrast mot vanlig +-- funktionsapplikation, vilket har den högsta utvärderingsprioriteten 10 och +-- associerar till vänster, har denna prioritetsordning 0 och är +-- högerassociativ. Denna låga prioritet medför att parameteruttrycket till +-- höger om operatorn får det reducerat innan det appliceras till sin vänster. + +-- före +even (fib 7) -- falskt + +-- ekvivalent +even $ fib 7 -- falskt + +-- med funktionskomposition +even . fib $ 7 -- falskt + + +---------------------------------------------------- +-- 5. Typsignaturer +---------------------------------------------------- + +-- Haskell har ett väldigt starkt typsystem, alla giltiga uttryck har en typ. + +-- Några grundläggande typer: +5 :: Integer +"hello" :: String +True :: Bool + +-- Funktioner har också typer, +-- `not` tar en bool och returnerar en bool: +-- not :: Bool -> Bool + +-- Här är ett exempel på en funktionssignatur vilken beskriver en funktion som +-- reducerar två heltal till ett: +-- add :: Integer -> Integer -> Integer + +-- Trots att Haskell härleder typen på icke typsatta uttryck är det bra form att +-- explicit ange dessa för ens deklarerade funktioner: +double :: Integer -> Integer +double x = x * 2 + +---------------------------------------------------- +-- 6. Kontrollflöde och Ifsatser +---------------------------------------------------- + +-- if-sats +haskell = if 1 == 1 then "awesome" else "awful" -- haskell = "awesome" + +-- if-statser kan spridas över rader men indentering har betydelse +haskell = if 1 == 1 + then "awesome" + else "awful" + +-- case uttryck: följande är ett exempel på kommandoradsparsning +case args of + "help" -> printHelp + "start" -> startProgram + _ -> putStrLn "bad args" + +-- Haskell har inte loopar istället används recursion. +-- map applicerar en funktion över varje element i en lista + +map (*2) [1..5] -- [2, 4, 6, 8, 10] + +-- man kan deklarera en for funktion genom att använda map +for array func = map func array + +-- och därefter använda den tillsammans med en anonym funktion för att +-- efterlikna en loop +for [0..5] $ \i -> show i + +-- men vi kunde även ha skrivit på följande vis: +for [0..5] show + +-- Du kan använda foldl eller foldr för att reducera en lista +-- foldl <fn> <initial value> <list> +foldl (\x y -> 2*x + y) 4 [1,2,3] -- 43 + +-- Vilket är samma sak som +(2 * (2 * (2 * 4 + 1) + 2) + 3) + +-- foldl viker från vänster, foldr från höger +foldr (\x y -> 2*x + y) 4 [1,2,3] -- 16 + +-- Vilket alltså är samma sak som +(2 * 1 + (2 * 2 + (2 * 3 + 4))) + +---------------------------------------------------- +-- 7. Datatyper +---------------------------------------------------- + +-- Såhär definierar du din egen datatyp i Haskell +data Color = Red | Blue | Green + +-- När du gjort det kan du använda den i funktionssignaturer och uttryck +say :: Color -> String +say Red = "Du är Rö!" +say Blue = "Du är Blå!" +say Green = "Du är Grön!" + +-- Dina datatyper kan även ta parametrar +data Maybe a = Nothing | Just a + +-- Följande uttryck är alla specialiseringar av typen Maybe +Just "hello" -- har typen `Maybe String` +Just 1 -- har typen `Maybe Int` +Nothing -- har typen `Maybe a` för alla `a` + +---------------------------------------------------- +-- 8. Haskell IO +---------------------------------------------------- + +-- Även om IO inte kan förstås fullt ut utan att först förklara monader är det +-- inte svårt att lära sig tillräckligt för att komma igång + +-- När ett Haskellprogram körs är det topnivåns main som körs. Main måste +-- returnerna ett värde av typen `IO a`, för någon typ `a`. Till exempel: + +main :: IO () +main = putStrLn $ "Hej, himmelen! " ++ (say Blue) +-- putStrLn har typen type String -> IO () + +-- Det är enkelt att göra IO om du kan implementera ditt program som en funktion +-- från String till String. Funktionen +-- interact :: (String -> String) -> IO () +-- tar denna funktion och matar den med strängdata från stdin och skriver ut +-- resultatet som en sträng på stdout + +countLines :: String -> String +countLines = show . length . lines + +main' = interact countLines + +-- Du kan tänka på värden av typen `IO ()` som att representera +-- händelsesekvenser du vill att din dator skall utföra, likt imperativa språk. +-- För att kedja ihop händelsesekvenser använder man ett syntaktiskt socker +-- kallat do-notation. Som exempel: + +sägHej :: IO () +sägHej = do + putStrLn "Vad heter du?" + namn <- getLine -- denna raden läser en rad från stdin och vi binder den till + -- funktionsnamnet `namn` + putStrLn $ "Hejsan, " ++ namn + +-- Övning: Skriv din egen version av interageringsfunktionen `interact` som bara +-- läser en rad från stdin, vanliga `interact` läser till EOF. + +-- Koden i sägHej kommer dock aldrig exekveras. Den enda handlingen som blir det +-- är som bekant utvärderingen av `main`. +-- För att köra `sägHej` kommentera ut definition av `main` ovan och +-- avkommentera nedanstående version: +-- main = sayHello + +-- Låt oss bättre förstå hur funktionen `getLine` vi just använde fungerar. Dess +-- typsignatur är: +-- getLine :: IO String +-- Du kan tänka på typen `IO a` som att representeras av ett datorprogram vilken +-- kommer generera ett värde av typen `a` när det exekveras (utöver allt annat +-- det kan tänkas göra). Vi kan därtill binda detta värde till ett namn för +-- återanvändning genom att använda `<-`. Vi kan även skapa våran egen handling +-- av typen `IO String`: + +handling :: IO String +handling = do + putStrLn "Detta är en rad, tihi" + input1 <- getLine + input2 <- getLine + -- Typen av hela `do` blocket är vad som står på sista raden. Här är även + -- `return` inte ett nyckelord i språket utan en funktion med en typsignatur + return (input1 ++ "\n" ++ input2) -- return :: String -> IO String + +-- Vi kan använda `return` på samma sätt som vi använde `getLine`: + +main'' = do + putStrLn "Jag kommer eka två rader!" + result <- handling + putStrLn result + putStrLn "Tack och hej leverpastej!" + +-- Typen `IO` är ett exempel på en monad. Sättet Haskell utnyttjar monader på är +-- anledningen till hur språket kan bibehålla sin renhet. En funktion vilken +-- interagerar med omvärlden (alltså gör IO) blir markerad med `IO` i sin +-- typsignatur. Detta låter oss enkelt upptäcka vilka funktioner som är "rena" +-- (inte interagerar med omvärlden eller är tillståndsoberoende) and vilka +-- funktioner som inte är det. + +-- Detta är ett mäktigt särdrag eftersom det är enkelt att köra rena funktioner +-- sammanlöpande; Samtidig programmering är enkel att göra i Haskell. + +---------------------------------------------------- +-- 9. Haskell REPL (kodtolk) +---------------------------------------------------- + +-- Efter installation av GHC kan vi starta tolken genom att skriva `ghci`. +-- Nu kan du mata in Haskellkod direkt i den. Nya värden måste introduceras med +-- `let` bindning: + +let foo = 5 + +-- Du kan även se typen av namnbindningen med `:t` + +> :t foo +foo :: Integer + +-- Operatorer, som `+`, `:` och `$` är funktioner. Deras typ kan inspekteras +-- genom att skriva operatorn mellan parenteser: + +> :t (:) +(:) :: a -> [a] -> [a] + +-- Du kan få ytterliggare information om något namn genom att använda `:i` + +> :i (+) +class Num a where + (+) :: a -> a -> a + ... + -- Defined in ‘GHC.Num’ +infixl 6 + + +-- Du kan även köra alla handlingar av typen `IO ()` direkt i tolken + +> sägHej +Vad är ditt namn? +Kompis! +Hello, Kompis! + +``` + +Det finns mycket mer att upptäcka med Haskell, inklusive typklasser och monader. +Vilka är de stora idéerna som gör Haskell till det roliga programmeringsspråket +det är. Jag lämar dig med ett sista exempel; En implementation av quicksort: + +```haskell +qsort [] = [] +qsort (p:xs) = qsort mindre ++ [p] ++ qsort större + where mindre = filter (< p) xs + större = filter (>= p) xs +``` + +Det finns två populära sätt att installera Haskell på: Den traditionella [Cabal sättet](http://www.haskell.org/platform/), eller det nyare [Stack sättet](https://www.stackage.org/install). + +Du kan finna vänligare och/eller djupare introduktioner till Haskell på engelska +från: +[Learn you a Haskell](http://learnyouahaskell.com/), +[Happy Learn Haskell Tutorial](http://www.happylearnhaskelltutorial.com/) eller +[Real World Haskell](http://book.realworldhaskell.org/). diff --git a/sv-se/nix-sv.html.markdown b/sv-se/nix-sv.html.markdown new file mode 100644 index 00000000..15d9456b --- /dev/null +++ b/sv-se/nix-sv.html.markdown @@ -0,0 +1,368 @@ +--- +language: nix +filename: learn-sv.nix +contributors: + - ["Chris Martin", "http://chris-martin.org/"] +translators: + - ["Edward Tjörnhammar", "http://edwtjo.me"] +lang: sv-se +--- + +Nix är ett enkelt funktionelt språk utvecklat för +[Nix pakethanteraren](https://nixos.org/nix/) och +[NixOS](https://nixos.org/) linuxdistributionen. + +Du kan utvärdera Nix uttryck genom att använda +[nix-instantiate](https://nixos.org/nix/manual/#sec-nix-instantiate) +eller [`nix-repl`](https://github.com/edolstra/nix-repl). + +``` +with builtins; [ + + # Kommentarer + #========================================= + + # Inlinekommentarer ser ut såhär. + + /* Flerradskommentarer ser ut + såhär. */ + + + # Booleaner + #========================================= + + (true && false) # Och + #=> false + + (true || false) # Eller + #=> true + + (if 3 < 4 then "a" else "b") # Villkorlig + #=> "a" + + + # Heltal + #========================================= + + # Heltal är den enda numeriska typen. + + 1 0 42 (-3) # Några heltal + + (4 + 6 + 12 - 2) # Addition + #=> 20 + + (7 / 2) # Division + #=> 3 + + + # Strängar + #========================================= + + "Stränglitteraler omgärdas av raka citationstecken." + + " + Stränglitteraler kan sträcka sig + över flera rader. + " + + '' + Detta kallas för en indenterad strängliteral, omgärdad av dubbla apostrofer + Den plockar intelligent bort ledande blanktecken. + '' + + '' + a + b + '' + #=> "a\n b" + + ("ab" + "cd") # Strängkonkatenering + #=> "abcd" + + # Antikvotering låter dig bädda in språkvärden i strängar. + ("Din hemkatalog är ${getEnv "HOME"}") + #=> "Din hemkatalog är /home/alice" + + + # Sökvägar + #========================================= + + # Nix har en primitiv, inbyggd, typ för sökvägar. + /tmp/tutorials/learn.nix + + # Relativa sökvägar förenas med sökvägen till dess definerande fils sökväg + # vid tolkningstillfället för att skapa dess absoluta sökväg. + + tutorials/learn.nix + #=> /the-base-path/tutorials/learn.nix + + # En sökväg måste innehålla åtminstonde ett snedstreck, så en relativ sökväg + # till en fil i samma katalog måste ges ett "./" prefix + + ./learn.nix + #=> /the-base-path/learn.nix + + # Divisionsoperatorn / måste omges av blanksteg om man vill att det skall + # tolkas som heltalsdivision + + 7/2 # Detta är en sökväg + (7 / 2) # Detta är heltalsdivision + + + # Importer + #========================================= + + # En nix fil innehåller ett enstaka topnivåuttryck utan fria variabler. + # Ett importuttryck evalueras till värdet på filen som den importerar. + (import /tmp/foo.nix) + + # Importer kan också specificeras med hjälp av strängar. + (import "/tmp/foo.nix") + + # Importsökvägar måste vara absoluta. Sökvägslitteraler härleds vid + # tolkningstillfället så följande är ok. + (import ./foo.nix) + + # Men detta är inte något som sker med strängar. + (import "./foo.nix") + #=> error: string ‘foo.nix’ doesn't represent an absolute path + + + # Let + #========================================= + + # `let` block tillåter oss att binda värden till namn. + (let x = "a"; in + x + x + x) + #=> "aaa" + + # Bindingar kan referera till varandra och deras ordning sinsemellan spelar + # ingen roll. + (let y = x + "b"; + x = "a"; in + y + "c") + #=> "abc" + + # Innre bindningar skuggar utanpåliggande bindingar. + (let a = 1; in + let a = 2; in + a) + #=> 2 + + + # Funktioner + #========================================= + + (n: n + 1) # En lambdafunktion som lägger till 1 + + ((n: n + 1) 5) # Samma funktion applicerad på 5 + #=> 6 + + # Det finns ingen syntax för direkt namngivna funktioner, istället binder man + # dessa med `let` block som andra värden. + (let succ = (n: n + 1); in succ 5) + #=> 6 + + # En funktion är en lambda med en parameter. Flera parameterar kan ges med + # hjälp av currying. + ((x: y: x + "-" + y) "a" "b") + #=> "a-b" + + # Vi kan också ha namngivna funktionsparametrar, vilket vi kommer komma till + # senare, efter att vi introducerat attributset. + + # Listor + #========================================= + + # Listor noteras med hakparenteser. + + (length [1 2 3 "x"]) + #=> 4 + + ([1 2 3] ++ [4 5]) + #=> [1 2 3 4 5] + + (concatLists [[1 2] [3 4] [5]]) + #=> [1 2 3 4 5] + + (head [1 2 3]) + #=> 1 + (tail [1 2 3]) + #=> [2 3] + + (elemAt ["a" "b" "c" "d"] 2) + #=> "c" + + (elem 2 [1 2 3]) + #=> true + (elem 5 [1 2 3]) + #=> false + + (filter (n: n < 3) [1 2 3 4]) + #=> [ 1 2 ] + + + # Mängder + #========================================= + + # Ett attributset är en oordnad mappning av strängnycklar och värden. + { foo = [1 2]; bar = "x"; } + + # Punktoperatorn . väljer ett värde från attributset:et + { a = 1; b = 2; }.a + #=> 1 + + # Frågeoperatorn ? testar om en nyckel är närvarande i ett attributset + ({ a = 1; b = 2; } ? a) + #=> true + ({ a = 1; b = 2; } ? c) + #=> false + + # Snedstrecksoperatorn // slår ihop två attributset:ar. + ({ a = 1; } // { b = 2; }) + #=> { a = 1; b = 2; } + + # Värden på höger skriver över värden till vänster. + ({ a = 1; b = 2; } // { a = 3; c = 4; }) + #=> { a = 3; b = 2; c = 4; } + + # Recursionsnyckelordet rec noterar ett rekursivt attributset (en fixpunkt) + # i vilket attributen kan referera till varandra. + (let a = 1; in { a = 2; b = a; }.b) + #=> 1 + (let a = 1; in rec { a = 2; b = a; }.b) + #=> 2 + + # Nästlade attributset:ar kan definieras bit för bit. + { + a.b = 1; + a.c.d = 2; + a.c.e = 3; + }.a.c + #=> { d = 2; e = 3; } + + # Ett attributsets barn kan inte tilldelas på detta vis om attributsetet + # självt blivit direkt tilldelat. + { + a = { b = 1; }; + a.c = 2; + } + #=> error: attribute ‘a’ already defined + + + # Bindningsintroduktion, `with` + #========================================= + + # Det attributset vilket återfinns i ett `with` uttryck kommer få sina + # värdebindningar introducerade i efterkommande uttryck. + (with { a = 1; b = 2; }; + a + b) + # => 3 + + # Innre bindningar skuggar yttre bindningar. + (with { a = 1; b = 2; }; + (with { a = 5; }; + a + b)) + #=> 7 + + # Första raden av detta exempel börjar med "with builtins;" eftersom builtins + # är ett attributset innehållande alla inbyggda hjälpfunktioner såsom + # (length, head, tail, filter, etc.). Detta sparar oss från att hela tiden + # referera in i det attributset:et , alltså du kan använda bara "length" + # istället för "builtins.length". + + + # Attributsetmönster + #========================================= + + # Attributset är användbara när vi skall skicka med flera värden till en + # funktion. + (args: args.x + "-" + args.y) { x = "a"; y = "b"; } + #=> "a-b" + + # Man kan använda attributsetmönster för ökad tydlighet. + ({x, y}: x + "-" + y) { x = "a"; y = "b"; } + #=> "a-b" + + # Attributmönster misslyckas dock om det medskickade attributmönstret + # innehåller extra nycklar. + ({x, y}: x + "-" + y) { x = "a"; y = "b"; z = "c"; } + #=> error: anonymous function called with unexpected argument ‘z’ + + # Genom att lägga till ", ..." kan vi ignorera ytterliggare nycklar. + ({x, y, ...}: x + "-" + y) { x = "a"; y = "b"; z = "c"; } + #=> "a-b" + + + # Felmeddelanden + #========================================= + + # `throw` gör att programtolken gör abort med dess tillhörande felmeddelande + causes evaluation to abort with an error message. + (2 + (throw "foo")) + #=> error: foo + + # `tryEval` fångar kastade fel `throw`. + (tryEval 42) + #=> { success = true; value = 42; } + (tryEval (2 + (throw "foo"))) + #=> { success = false; value = false; } + + # `abort` fungerar som `throw`, men är kritiskt och kan inte fångas. + (tryEval (abort "foo")) + #=> error: evaluation aborted with the following error message: ‘foo’ + + # `assert` utvärderas till det givna värdet om dess predikat är sant. + # annars skickar den ett fångbart fel. + (assert 1 < 2; 42) + #=> 42 + (assert 1 > 2; 42) + #=> error: assertion failed at (string):1:1 + (tryEval (assert 1 > 2; 42)) + #=> { success = false; value = false; } + + + # Orenhet + #========================================= + + # Eftersom repeterbarhet för byggen är en kritisk egenskap för + # Nix-pakethanteraren betonas funktionell renhet i Nix-programmeringsspråket. + # Men med det sagt existerar det källor till orenhet + + # Man kan referera till miljövariabler. + (getEnv "HOME") + #=> "/home/alice" + + # `trace` funktionen används för att debugga. Den skriver ut första argumentet + # till stderr och reduceras samtidigt till det andra argumentet. + (trace 1 2) + #=> trace: 1 + #=> 2 + + # Man kan skriva filer till Nix-store, lagringsplatsen för alla Nix-uttryck. + # Även om detta är orent beteende är det hyfsat säkert eftersom filens + # lagringsplats är härledd från dess innehåll och beroenden. Man kan läsa + # filer från precis överallt. I nedanstående exempel skriver vi en fil till + # Nix-store och sedan läser tillbaka den. + + (let filename = toFile "foo.txt" "hello!"; in + [filename (builtins.readFile filename)]) + #=> [ "/nix/store/ayh05aay2anx135prqp0cy34h891247x-foo.txt" "hello!" ] + + # Vi kan också ladda ned filer till Nix-store. + (fetchurl "https://example.com/package-1.2.3.tgz") + #=> "/nix/store/2drvlh8r57f19s9il42zg89rdr33m2rm-package-1.2.3.tgz" + +] +``` + +### Vidare Läsning (eng) + +* [Nix Manual - Nix expression language] + (https://nixos.org/nix/manual/#ch-expression-language) + +* [James Fisher - Nix by example - Part 1: The Nix expression language] + (https://medium.com/@MrJamesFisher/nix-by-example-a0063a1a4c55) + +* [Susan Potter - Nix Cookbook - Nix By Example] + (http://funops.co/nix-cookbook/nix-by-example/) diff --git a/tr-tr/css-tr.html.markdown b/tr-tr/css-tr.html.markdown new file mode 100644 index 00000000..d13dadcc --- /dev/null +++ b/tr-tr/css-tr.html.markdown @@ -0,0 +1,304 @@ +--- +language: css +contributors: + - ["Mohammad Valipour", "https://github.com/mvalipour"] + - ["Marco Scannadinari", "https://github.com/marcoms"] + - ["Geoffrey Liu", "https://github.com/g-liu"] + - ["Connor Shea", "https://github.com/connorshea"] + - ["Deepanshu Utkarsh", "https://github.com/duci9y"] + - ["Brett Taylor", "https://github.com/glutnix"] + - ["Tyler Mumford", "https://tylermumford.com"] +filename: learncss-tr.css +translators: + - ["Fatih Turan", "http://fatihturan.com"] +lang: tr-tr +--- + +Web sayfaları bir sayfanın içeriğini belirleyen HTML ile inşa edilirler. CSS (Basamaklı Biçim Sayfaları) ise bir sayfanın **görünümünü** belirleyen ayrı bir dildir. + +CSS kodu statik *kurallardan* oluşur. Her kural bir ya da daha fazla *seçici* alır ve görsel *özelliklere* belirli *değerleri* verir. Sonrasında bu özellikler seçiciler tarafından belirlenen sayfa unsurlarına uygulanır. + +Bu rehber, CSS 3'ün yeni özellikleri ile genişletilen CSS 2 ile dikkate alınarak yazılmıştır. + +**NOT:** CSS görsel sonuçlar ürettiğinden dolayı, öğrenmek için herşeyi bir CSS oyun alanı içinde ([dabblet](http://dabblet.com) gibi) denemeniz gerekmektedir. Bu makale sözdizimi kuralları ve genel ipuçları üzerine odaklanmaktadır. + +## Sözdizimi + +```css +/* yorumlar bu satırdaki gibi taksim-yıldız içinde görünür +CSS'te "tek satırlık yorumlar" bulunmamaktadır; bu sadece tek bir yorum yazma stilidir */ + +/* #################### + ## SEÇİCİLER + #################### */ + +/* seçici bir sayfadaki unsuru hedeflemek için kullanılır. */ +seçici { özellik: değer; /* daha fazla özellikler...*/ } + +/* +İşte bir örnek: + +<div class='class1 class2' id='anID' attr='value' otherAttr='en-us foo bar' /> +*/ + +/* */ + +/* CSS sınıflarının birini kullanarak hedefleyebilirsiniz */ +.class1 { } + +/* veya her iki sınıfı birden!*/ +.class1.class2 { } + +/* veya sadece ögenin adını yazarak */ +div { } + +/* veya onun ID adını */ +#anID { } + +/* veya onun aldığı bir özelliği kullanarak! */ +[attr] { font-size:smaller; } + +/* veya onun aldığı özelliğin belirli bir değeri varsa */ +[attr='value'] { font-size:smaller; } + +/* bir değer ile başlıyorsa (CSS 3) */ +[attr^='val'] { font-size:smaller; } + +/* veya bir değer ile bitiyorsa (CSS 3)*/ +[attr$='ue'] { font-size:smaller; } + +/* veya boşlukla ayrılmış liste içinde bir değer içeriyorsa */ +[otherAttr~='foo'] { } +[otherAttr~='bar'] { } + +/* veya tire ile ayrılmış bir liste içinde bir değer içeriyorsa, örneğin: "-" (U+002D) */ +[otherAttr|='en'] { font-size:smaller; } + +/* Farklı seçicileri birleştirerek daha fazla odaklanmış bir seçici oluşturabilirsiniz. Seçiciler arasında boşluk bırakmayın. */ +div.some-class[attr$='ue'] { } + +/* Başka bir ögenin alt ögesi olan bir ögeyi seçebilirsiniz. */ +div.some-parent > .class-name { } + +/* veya bir başka ögeden türeyeni seçebilirsiniz. Alt ögeler onların ebeveynlerinin direkt türünden gelir, sadece ağacın bir alt ögeleridirler. Soyundan gelenler ağacın herhangi bir alt seviyesinde olabilir. */ + +div.some-parent .class-name { } + +/* Uyarı: Seçiciler arasında bir boşluk bırakmazsanız aynı seçicinin başka bir anlamı olur. +Ne olduğunu tahmin edebilir misiniz? */ + +div.some-parent.class-name { } + +/* Ayrıca bir ögenin bitişik kardeşini temel alarak bir ögeyi seçebilirsiniz. */ +.i-am-just-before + .this-element { } + +/* veya kendisinden önce gelen herhangi bir kardeş ögeyi */ +.i-am-any-element-before ~ .this-element { } + +/* Yalnızca belli bir durumda bir öge seçmek için kullanılan sahte sınıflar adı verilen bazı seçiciler vardır. */ + +/* Örneğin, imleç bir ögenin üzerine geldiğinde */ +selector:hover { } + +/* veya bir bağlantı ziyaret edildiğinde */ +selector:visited { } + +/* veya ziyaret edilmediğinde */ +selected:link { } + +/* veya bir ögeye odaklanıldığında */ +selected:focus { } + +/* Ebeveyninin ilk alt ögesi olan herhangi bir öge */ +selector:first-child {} + +/* Ebeveyninin son alt ögesi olan herhangi bir öge */ +selector:last-child {} + +/* Sahte sınıflar gibi sahte elementler de bir dokümanın belirli bir parçasına stil vermenize izin verir. */ + +/* Seçilen ögenin sanal ilk alt ögesiyle eşleşir. */ +selector::before {} + +/* Seçilen ögenin sanal son alt ögesiyle eşleşir. */ +selector::after {} + +/* Uygun yerlerde yıldız karakteri ile bütün ögeleri seçmek için joker olarak kullanılabilir. */ + +* { } /* Bütün ögeler */ +.parent * { } /* Tüm alt ögeler */ +.parent > * { } /* Tüm çocuk ögeler */ + +/* #################### + ## ÖZELLİKLER + #################### */ + +selector { + + /* Ölçü birimleri kesin veya göreceli olabilir.*/ + + /* Göreceli birimler */ + width: 50%; /* Ebeveyn elementin yüzdesel olarak genişliği */ + font-size: 2em; /* Öğenin özgün yazı tipi boyutunda katları */ + font-size: 2rem; /* veya kök ögenin yazı tipi boyutu */ + font-size: 2vw; /* Görüntüleme çerçevesinin genişliğinin %1 olarak katları (CSS 3) */ + font-size: 2vh; /* veya onun yüksekliğinin */ + font-size: 2vmin; /* Bir vh veya vw'nin hangisi küçükse */ + font-size: 2vmax; /* veya daha büyük... */ + + /* Kesin birimler */ + width: 200px; /* Piksel */ + font-size: 20pt; /* Nokta */ + width: 5cm; /* Santimetre */ + min-width: 50mm; /* Milimetre */ + max-width: 5in; /* İnç */ + + /* Renkler */ + color: #F6E; /* Kısa onaltılık (HEX) biçimi */ + color: #FF66EE; /* Uzun onaltılık (HEX) biçimi */ + color: tomato; /* Bir isim verilen renk */ + color: rgb(255, 255, 255); /* RGB değerleri verilen türde */ + color: rgb(10%, 20%, 50%); /* RGB yüzdeleri verilen türde */ + color: rgba(255, 0, 0, 0.3); /* RGBA değerleri verilen türde (CSS 3) Not: 0 <= a <= 1 */ + color: transparent; /* Şeffaflık değerinin sıfır olması ile eşdeğer */ + color: hsl(0, 100%, 50%); /* HSL yüzdeleri verilen türde (CSS 3) */ + color: hsla(0, 100%, 50%, 0.3); /* HSL ile beraber şeffaflık değeri verilen türde */ + + /* Kenarlıklar */ + border-width:5px; + border-style:solid; + border-color:red; /* background-color'ın ayarlanışına benzer şekilde */ + border: 5px solid red; /* Bu aynı şeyin kısayol ile yazılışıdır */ + border-radius:20px; /* Bu bir CSS3 özelliğidir */ + + /* Görseller ve Ögelerin Arkaplanları */ + background-image: url(/img-path/img.jpg); /* url() içindeki tırnak işaretleri isteğe bağlı */ + + /* Yazı tipleri */ + font-family: Arial; + /* Eğer yazı tipi ailesi isminde bir boşluk var ise tırnak işareti içine alınmalıdır. */ + font-family: "Courier New"; + /* Eğer ilk sıradaki bulunamazsa, tarayıcı bir sonrakini kullanır */ + font-family: "Courier New", Trebuchet, Arial, sans-serif; +} +``` + +## Kullanım + +CSS dosyasınızı `.css`uzantısı ile kaydedin. + +```html +<!-- CSS dosyanızı sayfanın içindeki <head> alanına dahil etmeniz gerekiyor. Bu önerilen yöntemdir. Bakın: http://stackoverflow.com/questions/8284365 --> +<link rel='stylesheet' type='text/css' href='path/to/style.css'> + +<!-- Bazı CSS kodları satır içi olarak yazabilirsiniz. --> +<style> + a { color: purple; } +</style> + +<!-- Veya ögenin üzerinde CSS özelliklerini direkt ayarlayabilirsiniz. --> +<div style="border: 1px solid red;"> +</div> +``` + +## Öncelik veya Basamak + +Bir öge birden çok seçici tarafından hedef alınabilir ve bir özellik kümesine birden fazla kez sahip olabilir. Bunun gibi durumlarda, kurallardan biri diğerlerine göre önceliklidir. Daha spesifik bir seçiciye sahip kurallar, daha az spesifik bir seçicinin önceliğini alır ve kural daha sonra stil sayfasında bir önceki kuralın üzerine yazar. + +Bu işleme geçiş denir ve olayısıyla Geçişli/Basamaklı Stil Sayfaları adı da buradan gelmiştir. + +Aşağıdaki CSS göz önüne alındığında: + +```css +/* A */ +p.class1[attr='değer'] + +/* B */ +p.class1 { } + +/* C */ +p.class2 { } + +/* D */ +p { } + +/* E */ +p { özellik: değer !important; } +``` + +ve aşağıdaki biçimlendirmeyi: + +```html +<p style='/*F*/ özellik:değer;' class='class1 class2' attr='değer'> +``` + +Stilin önceliği ise aşağıdaki gibidir. Unutmayın, öncelik **her bir özellik için ayrı ayrı geçerlidir**, tüm blok için geçerli değildir. + +* `E` `!important` kelimesi yüzünden en yüksek önceliğe sahiptir. Kullanımından kaçınmanız önerilir. +* `F` satıriçi stil olduğu için bir sonraki önceliğe sahiptir. +* `A` bir sonraki önceliğe sahiptir. Çünkü her şeyden daha "özgüdür". 3 belirteci vardır: `p` ögesinin adı, sınıf` class1`, bir öznitelik `attr = 'değer'. +* `C`, `B` ile aynı özdeşliğe sahip olsa da, bundan sonra geldiğinden dolayı öncelik hakkına sahiptir. +* `B` bir sonraki önceliğe sahiptir. +* Sonuncu önceliğe sahip olan`D`'dir. + +## Medya Sorguları + +CSS Medya Sorguları, CSS 3'te belirli CSS kurallarının ne zaman uygulanması gerektiğini (örneğin basılan zaman veya belirli boyutlar veya piksel yoğunluğu olan bir ekranda olduğunda) belirlemenize izin veren bir özelliktir. Medya Sorguları, seçicilere önceliğk eklemez. + +```css +/* Tüm cihazlarda kullanılacak olan bir kural */ +h1 { + font-size: 2em; + color: white; + background-color: black; +} + +/* h1 ögesini değiştirip bir yazıcıda daha az mürekkep kullanın*/ +@media print { + h1 { + color: black; + background-color: white; + } +} + +/* En az 480 piksel genişliğinde bir ekran gösterildiğinde font yüksekliğini daha büyük yap */ +@media screen and (min-width: 480px) { + h1 { + font-size: 3em; + font-weight: normal; + } +} +``` + +Medya sorguları aşağıdaki bu özellikleri içerebilir: +`width`, `height`, `device-width`, `device-height`, `orientation`, `aspect-ratio`, `device-aspect-ratio`, `color`, `color-index`, `monochrome`, `resolution`, `scan`, `grid`. Bu özelliklerin birçoğunu `min-` veya `max-` öneki ile kullanabilirsiniz. + +`resolution` özelliği eski cihazlarda desteklenmediğinden ötürü `device-pixel-ratio` kullanın. + +Eğer `viewport` meta etiketi sağlanmadıkça birçok akıllı telefon ve tabletler, sayfayı masaüstü bilgisayardaymış gibi göstermeye çalışacaktır. + +```html +<head> + <meta name="viewport" content="width=device-width; initial-scale=1.0"> +</head> +``` + +## Uyumluluk + +CSS 2'deki çoğu özellik (ve CSS 3'deki birçoğu) bütün tarayıcılar ve cihazlar için bulunmaktadır. Ancak yeni bir özelliği kullanmadan önce kontrol etmek her zaman iyi bir uygulamadır. + +## Kaynaklar + +* [CanIUse](http://caniuse.com) (Detaylı uyumluluk bilgileri) +* [Dabblet](http://dabblet.com/) (CSS oyun alanı) +* [Mozilla Geliştirici Ağının CSS belgelendirmesi](https://developer.mozilla.org/en-US/docs/Web/CSS) (Eğitseller ve referanslar) +* [Codrops' CSS Referansı](http://tympanus.net/codrops/css_reference/) (Referans) + +## Daha Fazla Okuma + +* [Understanding Style Precedence in CSS: Specificity, Inheritance, and the Cascade](http://www.vanseodesign.com/css/css-specificity-inheritance-cascaade/) +* [Selecting elements using attributes](https://css-tricks.com/almanac/selectors/a/attribute/) +* [QuirksMode CSS](http://www.quirksmode.org/css/) +* [Z-Index - The stacking context](https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Understanding_z_index/The_stacking_context) +* [SASS](http://sass-lang.com/) and [LESS](http://lesscss.org/) for CSS pre-processing +* [CSS-Tricks](https://css-tricks.com) diff --git a/typescript.html.markdown b/typescript.html.markdown index 10f01ebc..acc258b4 100644 --- a/typescript.html.markdown +++ b/typescript.html.markdown @@ -29,7 +29,7 @@ let notSure: any = 4; notSure = "maybe a string instead"; notSure = false; // okay, definitely a boolean -// Use const keyword for constant variables +// Use const keyword for constants const numLivesForCat = 9; numLivesForCat = 1; // Error diff --git a/vim.html.markdown b/vim.html.markdown index 15144b8d..d5c4e865 100644 --- a/vim.html.markdown +++ b/vim.html.markdown @@ -21,6 +21,7 @@ specific points in the file, and for fast editing. :q # Quit vim :w # Save current file :wq # Save file and quit vim + ZZ # Save file and quit vim :q! # Quit vim without saving file # ! *forces* :q to execute, hence quiting vim without saving :x # Save file and quit vim, shorter version of :wq @@ -48,6 +49,7 @@ specific points in the file, and for fast editing. :%s/foo/bar/g # Change 'foo' to 'bar' on every line in the file :s/foo/bar/g # Change 'foo' to 'bar' on the current line + :%s/\n/\r/g # Replace new line characters with new line characters # Jumping to characters @@ -167,6 +169,20 @@ A few important examples of 'Verbs', 'Modifiers', and 'Nouns': ddp # Swap position of consecutive lines, dd then p . # Repeat previous action :w !sudo tee % # Save the current file as root + :set syntax=c # Set syntax highlighting to 'c' + :sort # Sort all lines + :sort! # Sort all lines in reverse + :sort u # Sort all lines and remove duplicates + ~ # Toggle letter case of selected text + u # Selected text to lower case + U # Selected text to upper case + + # Fold text + zf # Create fold from selected text + zo # Open current fold + zc # Close current fold + zR # Open all folds + zM # Close all folds ``` ## Macros diff --git a/yaml.html.markdown b/yaml.html.markdown index 3b32a069..52658453 100644 --- a/yaml.html.markdown +++ b/yaml.html.markdown @@ -2,8 +2,8 @@ language: yaml filename: learnyaml.yaml contributors: - - ["Adam Brenecki", "https://github.com/adambrenecki"] - - ["Suhas SG", "https://github.com/jargnar"] +- [Adam Brenecki, 'https://github.com/adambrenecki'] +- [Suhas SG, 'https://github.com/jargnar'] --- YAML is a data serialisation language designed to be directly writable and @@ -11,7 +11,7 @@ readable by humans. It's a strict superset of JSON, with the addition of syntactically significant newlines and indentation, like Python. Unlike Python, however, -YAML doesn't allow literal tab characters at all. +YAML doesn't allow literal tab characters for indentation. ```yaml # Comments in YAML look like this. @@ -32,8 +32,10 @@ boolean: true null_value: null key with spaces: value # Notice that strings don't need to be quoted. However, they can be. -however: "A string, enclosed in quotes." -"Keys can be quoted too.": "Useful if you want to put a ':' in your key." +however: 'A string, enclosed in quotes.' +'Keys can be quoted too.': "Useful if you want to put a ':' in your key." +single quotes: 'have ''one'' escape pattern' +double quotes: "have many: \", \0, \t, \u263A, \x0d\x0a == \r\n, and more." # Multiple-line strings can be written either as a 'literal block' (using |), # or a 'folded block' (using '>'). @@ -59,12 +61,12 @@ folded_style: > # COLLECTION TYPES # #################### -# Nesting is achieved by indentation. +# Nesting uses indentation. 2 space indent is preferred (but not required). a_nested_map: - key: value - another_key: Another Value - another_nested_map: - hello: hello + key: value + another_key: Another Value + another_nested_map: + hello: hello # Maps don't have to have string keys. 0.25: a float key @@ -72,8 +74,8 @@ a_nested_map: # Keys can also be complex, like multi-line objects # We use ? followed by a space to indicate the start of a complex key. ? | - This is a key - that has multiple lines + This is a key + that has multiple lines : and this is its value # YAML also allows mapping between sequences with the complex key syntax @@ -83,22 +85,26 @@ a_nested_map: - Real Madrid : [ 2001-01-01, 2002-02-02 ] -# Sequences (equivalent to lists or arrays) look like this: +# Sequences (equivalent to lists or arrays) look like this +# (note that the '-' counts as indentation): a_sequence: - - Item 1 - - Item 2 - - 0.5 # sequences can contain disparate types. - - Item 4 - - key: value - another_key: another_value - - - - This is a sequence - - inside another sequence +- Item 1 +- Item 2 +- 0.5 # sequences can contain disparate types. +- Item 4 +- key: value + another_key: another_value +- + - This is a sequence + - inside another sequence +- - - Nested sequence indicators + - can be collapsed # Since YAML is a superset of JSON, you can also write JSON-style maps and # sequences: json_map: {"key": "value"} json_seq: [3, 2, 1, "takeoff"] +and quotes are optional: {key: [3, 2, 1, takeoff]} ####################### # EXTRA YAML FEATURES # @@ -111,15 +117,15 @@ other_anchor: *anchor_name # Anchors can be used to duplicate/inherit properties base: &base - name: Everyone has same name + name: Everyone has same name foo: &foo - <<: *base - age: 10 + <<: *base + age: 10 bar: &bar - <<: *base - age: 20 + <<: *base + age: 20 # foo and bar would also have name: Everyone has same name @@ -147,22 +153,23 @@ date: 2002-12-14 # The !!binary tag indicates that a string is actually a base64-encoded # representation of a binary blob. gif_file: !!binary | - R0lGODlhDAAMAIQAAP//9/X17unp5WZmZgAAAOfn515eXvPz7Y6OjuDg4J+fn5 - OTk6enp56enmlpaWNjY6Ojo4SEhP/++f/++f/++f/++f/++f/++f/++f/++f/+ - +f/++f/++f/++f/++f/++SH+Dk1hZGUgd2l0aCBHSU1QACwAAAAADAAMAAAFLC - AgjoEwnuNAFOhpEMTRiggcz4BNJHrv/zCFcLiwMWYNG84BwwEeECcgggoBADs= + R0lGODlhDAAMAIQAAP//9/X17unp5WZmZgAAAOfn515eXvPz7Y6OjuDg4J+fn5 + OTk6enp56enmlpaWNjY6Ojo4SEhP/++f/++f/++f/++f/++f/++f/++f/++f/+ + +f/++f/++f/++f/++f/++SH+Dk1hZGUgd2l0aCBHSU1QACwAAAAADAAMAAAFLC + AgjoEwnuNAFOhpEMTRiggcz4BNJHrv/zCFcLiwMWYNG84BwwEeECcgggoBADs= # YAML also has a set type, which looks like this: set: - ? item1 - ? item2 - ? item3 + ? item1 + ? item2 + ? item3 +or: {item1, item2, item3} # Like Python, sets are just maps with null values; the above is equivalent to: set2: - item1: null - item2: null - item3: null + item1: null + item2: null + item3: null ``` ### More Resources diff --git a/zh-cn/crystal-cn.html.markdown b/zh-cn/crystal-cn.html.markdown new file mode 100644 index 00000000..14805114 --- /dev/null +++ b/zh-cn/crystal-cn.html.markdown @@ -0,0 +1,567 @@ +--- +language: crystal +filename: learncrystal-cn.cr +contributors: + - ["Vitalii Elenhaupt", "http://veelenga.com"] + - ["Arnaud Fernandés", "https://github.com/TechMagister/"] +translators: + - ["Xuty", "https://github.com/xtyxtyx"] +lang: zh-cn +--- + +```crystal + +# 这是一行注释 + +# 一切都是对象(object) +nil.class #=> Nil +100.class #=> Int32 +true.class #=> Bool + +# nil, false 以及空指针是假值(falsey values) +!nil #=> true : Bool +!false #=> true : Bool +!0 #=> false : Bool + +# 整数类型 + +1.class #=> Int32 + +# 四种有符号整数 +1_i8.class #=> Int8 +1_i16.class #=> Int16 +1_i32.class #=> Int32 +1_i64.class #=> Int64 + +# 四种无符号整数 +1_u8.class #=> UInt8 +1_u16.class #=> UInt16 +1_u32.class #=> UInt32 +1_u64.class #=> UInt64 + +2147483648.class #=> Int64 +9223372036854775808.class #=> UInt64 + +# 二进制数 +0b1101 #=> 13 : Int32 + +# 八进制数 +0o123 #=> 83 : Int32 + +# 十六进制数 +0xFE012D #=> 16646445 : Int32 +0xfe012d #=> 16646445 : Int32 + +# 浮点数类型 + +1.0.class #=> Float64 + +# Crystal中有两种浮点数 +1.0_f32.class #=> Float32 +1_f32.class #=> Float32 + +1e10.class #=> Float64 +1.5e10.class #=> Float64 +1.5e-7.class #=> Float64 + +# 字符类型 + +'a'.class #=> Char + +# 八进制字符 +'\101' #=> 'A' : Char + +# Unicode字符 +'\u0041' #=> 'A' : Char + +# 字符串 + +"s".class #=> String + +# 字符串不可变(immutable) +s = "hello, " #=> "hello, " : String +s.object_id #=> 134667712 : UInt64 +s += "Crystal" #=> "hello, Crystal" : String +s.object_id #=> 142528472 : UInt64 + +# 支持字符串插值(interpolation) +"sum = #{1 + 2}" #=> "sum = 3" : String + +# 多行字符串 +"这是一个 + 多行字符串" + +# 书写带有引号的字符串 +%(hello "world") #=> "hello \"world\"" + +# 符号类型 +# 符号是不可变的常量，本质上是Int32类型 +# 符号通常被用来代替字符串，来高效地传递特定的值 + +:symbol.class #=> Symbol + +sentence = :question? # :"question?" : Symbol + +sentence == :question? #=> true : Bool +sentence == :exclamation! #=> false : Bool +sentence == "question?" #=> false : Bool + +# 数组类型(Array) + +[1, 2, 3].class #=> Array(Int32) +[1, "hello", 'x'].class #=> Array(Int32 | String | Char) + +# 必须为空数组指定类型 +[] # Syntax error: for empty arrays use '[] of ElementType' +[] of Int32 #=> [] : Array(Int32) +Array(Int32).new #=> [] : Array(Int32) + +# 数组可以通过下标访问 +array = [1, 2, 3, 4, 5] #=> [1, 2, 3, 4, 5] : Array(Int32) +array[0] #=> 1 : Int32 +array[10] # raises IndexError +array[-6] # raises IndexError +array[10]? #=> nil : (Int32 | Nil) +array[-6]? #=> nil : (Int32 | Nil) + +# 使用负位置编号，从后往前访问数组 +array[-1] #=> 5 + +# With a start index and size +# 使用起始位置编号+大小 +array[2, 3] #=> [3, 4, 5] + +# 使用范围(range)访问数组 +array[1..3] #=> [2, 3, 4] + +# 向尾部添加元素 +array << 6 #=> [1, 2, 3, 4, 5, 6] + +# 删除尾部元素 +array.pop #=> 6 +array #=> [1, 2, 3, 4, 5] + +# 删除首部元素 +array.shift #=> 1 +array #=> [2, 3, 4, 5] + +# 检查元素是否存在与数组之中 +array.includes? 3 #=> true + +# 一种特殊语法，用来创建字符串数组或符号数组 +%w(one two three) #=> ["one", "two", "three"] : Array(String) +%i(one two three) #=> [:one, :two, :three] : Array(Symbol) + +# 对于定义了`new`和`#<<`方法的类，可以用以下语法创建新对象 +set = Set{1, 2, 3} #=> [1, 2, 3] +set.class #=> Set(Int32) + +# 以下代码与上方等同 +set = Set(typeof(1, 2, 3)).new +set << 1 +set << 2 +set << 3 + +# 哈希表类型(Hash) + +{1 => 2, 3 => 4}.class #=> Hash(Int32, Int32) +{1 => 2, 'a' => 3}.class #=> Hash(Int32 | Char, Int32) + +# 必须为空哈希表指定类型 +{} # Syntax error +{} of Int32 => Int32 # {} +Hash(Int32, Int32).new # {} + +# 可以使用键(key)快速查询哈希表 +hash = {"color" => "green", "number" => 5} +hash["color"] #=> "green" +hash["no_such_key"] #=> Missing hash key: "no_such_key" (KeyError) +hash["no_such_key"]? #=> nil + +# 检查某一键哈希表中是否存在 +hash.has_key? "color" #=> true + +# 对于定义了`#[]=`方法的类，可以使用以下语法创建对象 +class MyType + def []=(key, value) + puts "do stuff" + end +end + +MyType{"foo" => "bar"} + +# 以上与下列代码等同 +tmp = MyType.new +tmp["foo"] = "bar" +tmp + +# 范围类型(Range) + +1..10 #=> Range(Int32, Int32) +Range.new(1, 10).class #=> Range(Int32, Int32) + +# 包含或不包含端点 +(3..5).to_a #=> [3, 4, 5] +(3...5).to_a #=> [3, 4] + +# 检查某一值是否在范围内 +(1..8).includes? 2 #=> true + +# 元组类型(Tuple) + +# 元组类型尺寸固定，不可变，储存在栈中 +# 元组可以有不同类型的对象组成 +{1, "hello", 'x'}.class #=> Tuple(Int32, String, Char) + +# 使用下标访问元组 +tuple = {:key1, :key2} +tuple[1] #=> :key2 +tuple[2] #=> syntax error : Index out of bound + +# 将元组中的元素赋值给变量 +a, b, c = {:a, 'b', "c"} +a #=> :a +b #=> 'b' +c #=> "c" + +# 命名元组类型(NamedTuple) + +tuple = {name: "Crystal", year: 2011} # NamedTuple(name: String, year: Int32) +tuple[:name] # => "Crystal" (String) +tuple[:year] # => 2011 (Int32) + +# 命名元组的键可以是字符串常量 +{"this is a key": 1} # => NamedTuple("this is a key": Int32) + +# 过程类型(Proc) +# 过程代表一个函数指针，以及可选的上下文(闭包) +# 过程通常使用字面值创建 +proc = ->(x : Int32) { x.to_s } +proc.class # Proc(Int32, String) + +# 或者使用`new`方法创建 +Proc(Int32, String).new { |x| x.to_s } + +# 使用`call`方法调用过程 +proc.call 10 #=> "10" + +# 控制语句(Control statements) + +if true + "if 语句" +elsif false + "else-if, 可选" +else + "else, 同样可选" +end + +puts "可以将if后置" if true + +# 将if作为表达式 +a = if 2 > 1 + 3 + else + 4 + end + +a #=> 3 + +# 条件表达式 +a = 1 > 2 ? 3 : 4 #=> 4 + +# `case`语句 +cmd = "move" + +action = case cmd + when "create" + "Creating..." + when "copy" + "Copying..." + when "move" + "Moving..." + when "delete" + "Deleting..." +end + +action #=> "Moving..." + +# 循环 +index = 0 +while index <= 3 + puts "Index: #{index}" + index += 1 +end +# Index: 0 +# Index: 1 +# Index: 2 +# Index: 3 + +index = 0 +until index > 3 + puts "Index: #{index}" + index += 1 +end +# Index: 0 +# Index: 1 +# Index: 2 +# Index: 3 + +# 更好的做法是使用`each` +(0..3).each do |index| + puts "Index: #{index}" +end +# Index: 0 +# Index: 1 +# Index: 2 +# Index: 3 + +# 变量的类型取决于控制语句中表达式的类型 +if a < 3 + a = "hello" +else + a = true +end +typeof a #=> (Bool | String) + +if a && b + # 此处`a`与`b`均为Nil +end + +if a.is_a? String + a.class #=> String +end + +# 函数(Functions) + +def double(x) + x * 2 +end + +# 函数(以及所有代码块)均将最末尾表达式的值作为返回值 +double(2) #=> 4 + +# 在没有歧义的情况下，括号可以省略 +double 3 #=> 6 + +double double 3 #=> 12 + +def sum(x, y) + x + y +end + +# 使用逗号分隔参数 +sum 3, 4 #=> 7 + +sum sum(3, 4), 5 #=> 12 + +# yield +# 所有函数都有一个默认生成、可选的代码块(block)参数 +# 在函数中可以使用yield调用此代码块 + +def surround + puts '{' + yield + puts '}' +end + +surround { puts "hello world" } + +# { +# hello world +# } + + +# 可将代码块作为参数传给函数 +# "&" 表示对代码块参数的引用 +def guests(&block) + block.call "some_argument" +end + +# 使用星号"*"将参数转换成元组 +def guests(*array) + array.each { |guest| puts guest } +end + +# 如果函数返回数组，可以将其解构 +def foods + ["pancake", "sandwich", "quesadilla"] +end +breakfast, lunch, dinner = foods +breakfast #=> "pancake" +dinner #=> "quesadilla" + +# 按照约定，所有返回布尔值的方法都以问号结尾 +5.even? # false +5.odd? # true + +# 以感叹号结尾的方法，都有一些破坏性(destructive)行为，比如改变调用接收者(receiver) +# 对于某些方法，带有感叹号的版本将改变调用接收者，而不带有感叹号的版本返回新值 +company_name = "Dunder Mifflin" +company_name.gsub "Dunder", "Donald" #=> "Donald Mifflin" +company_name #=> "Dunder Mifflin" +company_name.gsub! "Dunder", "Donald" +company_name #=> "Donald Mifflin" + + +# 使用`class`关键字来定义类(class) +class Human + + # 类变量，由类的所有实例所共享 + @@species = "H. sapiens" + + # `name`的类型为`String` + @name : String + + # 构造器方法(initializer) + # 其中@name、@age为简写，相当于 + # + # def initialize(name, age = 0) + # @name = name + # @age = age + # end + # + # `age`为可选参数，如果未指定，则使用默认值0 + def initialize(@name, @age = 0) + end + + # @name的setter方法 + def name=(name) + @name = name + end + + # @name的getter方法 + def name + @name + end + + # 上述getter与setter的定义可以用property宏简化 + property :name + + # 也可用getter与setter宏独立创建getter与setter + getter :name + setter :name + + # 此处的`self.`使`say`成为类方法 + def self.say(msg) + puts msg + end + + def species + @@species + end +end + + +# 将类实例化 +jim = Human.new("Jim Halpert") + +dwight = Human.new("Dwight K. Schrute") + +# 调用一些实例方法 +jim.species #=> "H. sapiens" +jim.name #=> "Jim Halpert" +jim.name = "Jim Halpert II" #=> "Jim Halpert II" +jim.name #=> "Jim Halpert II" +dwight.species #=> "H. sapiens" +dwight.name #=> "Dwight K. Schrute" + +# 调用类方法 +Human.say("Hi") #=> 输出 Hi ，返回 nil + +# 带有`@`前缀的变量为实例变量 +class TestClass + @var = "I'm an instance var" +end + +# 带有`@@`前缀的变量为类变量 +class TestClass + @@var = "I'm a class var" +end +# 首字母大写的变量为常量 +Var = "这是一个常量" +Var = "无法再次被赋值" # 常量`Var`已经被初始化 + +# 在crystal中类也是对象(object)，因此类也有实例变量(instance variable) +# 类变量的定义由类以及类的派生类所共有，但类变量的值是独立的 + +# 基类 +class Human + @@foo = 0 + + def self.foo + @@foo + end + + def self.foo=(value) + @@foo = value + end +end + +# 派生类 +class Worker < Human +end + +Human.foo #=> 0 +Worker.foo #=> 0 + +Human.foo = 2 #=> 2 +Worker.foo #=> 0 + +Worker.foo = 3 #=> 3 +Human.foo #=> 2 +Worker.foo #=> 3 + +module ModuleExample + def foo + "foo" + end +end + +# include <Module> 将模块(module)中的方法添加为实例方法 +# extend <Module> 将模块中的方法添加为类方法 + +class Person + include ModuleExample +end + +class Book + extend ModuleExample +end + +Person.foo # => undefined method 'foo' for Person:Class +Person.new.foo # => 'foo' +Book.foo # => 'foo' +Book.new.foo # => undefined method 'foo' for Book + + +# 异常处理 + +# 定义新的异常类(exception) +class MyException < Exception +end + +# 再定义一个异常类 +class MyAnotherException < Exception; end + +ex = begin + raise MyException.new +rescue ex1 : IndexError + "ex1" +rescue ex2 : MyException | MyAnotherException + "ex2" +rescue ex3 : Exception + "ex3" +rescue ex4 # 捕捉任何类型的异常 + "ex4" +end + +ex #=> "ex2" + +``` + +## 参考资料 + +- [官方网站](https://crystal-lang.org/) +- [官方文档](https://crystal-lang.org/docs/overview/) +- [在线运行代码](https://play.crystal-lang.org/#/cr) +- [Github仓库](https://github.com/crystal-lang/crystal) diff --git a/zh-cn/kotlin-cn.html.markdown b/zh-cn/kotlin-cn.html.markdown index 5d655029..f6dcd847 100644 --- a/zh-cn/kotlin-cn.html.markdown +++ b/zh-cn/kotlin-cn.html.markdown @@ -22,7 +22,7 @@ package com.learnxinyminutes.kotlin /* Kotlin程序的入口点是一个"main"函数 -该函数传递一个包含任何命令行参数的数组。 +该函数传递一个包含所有命令行参数的数组。 */ fun main(args: Array<String>) { /* @@ -67,10 +67,10 @@ fun helloWorld(val name : String) { 模板表达式从一个美元符号($)开始。 */ val fooTemplateString = "$fooString has ${fooString.length} characters" - println(fooTemplateString) + println(fooTemplateString) // => 输出 My String Is Here! has 18 characters /* - 当某个变量的值可以为 null 的时候，我们必须被明确指定它是可为空的。 + 当某个变量的值可以为 null 的时候，我们必须明确指定它是可为空的。 在变量声明处的类型后面加上?来标识它是可为空的。 我们可以用?.操作符来访问可为空的变量。 我们可以用?:操作符来指定一个在变量为空时使用的替代值。 @@ -96,24 +96,24 @@ fun helloWorld(val name : String) { println(hello()) // => Hello, world! /* - 用"vararg"关键字来修饰一个函数的参数来允许可变参数传递给该函数 + 函数的可变参数可使用 "vararg" 关键字来修饰 */ fun varargExample(vararg names: Int) { println("Argument has ${names.size} elements") } - varargExample() // => Argument has 0 elements - varargExample(1) // => Argument has 1 elements - varargExample(1, 2, 3) // => Argument has 3 elements + varargExample() // => 传入 0 个参数 + varargExample(1) // => 传入 1 个参数 + varargExample(1, 2, 3) // => 传入 3 个参数 /* - 当函数只包含一个单独的表达式时，大括号可以被省略。 - 函数体可以被指定在一个=符号后面。 + 当函数只包含一个单独的表达式时，大括号可以省略。 + 函数体可以写在一个=符号后面。 */ fun odd(x: Int): Boolean = x % 2 == 1 println(odd(6)) // => false println(odd(7)) // => true - // 如果返回值类型可以被推断，那么我们不需要指定它。 + // 如果返回值类型可以推断，那么我们不需要指定它。 fun even(x: Int) = x % 2 == 0 println(even(6)) // => true println(even(7)) // => false @@ -122,15 +122,14 @@ fun helloWorld(val name : String) { fun not(f: (Int) -> Boolean) : (Int) -> Boolean { return {n -> !f.invoke(n)} } - // 命名函数可以用::运算符被指定为参数。 + // 普通函数可以用::运算符传入引用作为函数参数。 val notOdd = not(::odd) val notEven = not(::even) - // 匿名函数可以被指定为参数。 + // lambda 表达式可以直接作为参数传递。 val notZero = not {n -> n == 0} /* - 如果一个匿名函数只有一个参数 - 那么它的声明可以被省略（连同->）。 - 这个参数的名字是"it"。 + 如果一个 lambda 表达式只有一个参数 + 那么它的声明可以省略（连同->），内部以 "it" 引用。 */ val notPositive = not {it > 0} for (i in 0..4) { @@ -152,7 +151,7 @@ fun helloWorld(val name : String) { 注意，Kotlin没有"new"关键字。 */ val fooExampleClass = ExampleClass(7) - // 可以使用一个点号来调用成员函数。 + // 可以使用一个点号来调用成员方法。 println(fooExampleClass.memberFunction(4)) // => 11 /* 如果使用"infix"关键字来标记一个函数 @@ -162,7 +161,7 @@ fun helloWorld(val name : String) { /* 数据类是创建只包含数据的类的一个简洁的方法。 - "hashCode"、"equals"和"toString"方法将被自动生成。 + "hashCode"、"equals"和"toString"方法将自动生成。 */ data class DataClassExample (val x: Int, val y: Int, val z: Int) val fooData = DataClassExample(1, 2, 4) diff --git a/zh-cn/make-cn.html.markdown b/zh-cn/make-cn.html.markdown new file mode 100644 index 00000000..4cdf1e63 --- /dev/null +++ b/zh-cn/make-cn.html.markdown @@ -0,0 +1,262 @@ +--- +language: make +contributors: +- ["Robert Steed", "https://github.com/robochat"] +- ["Jichao Ouyang", "https://github.com/jcouyang"] +translators: +- ["Jichao Ouyang", "https://github.com/jcouyang"] +filename: Makefile-cn +lang: zh-cn +--- + +Makefile 用于定义如何创建目标文件, 比如如何从源码到可执行文件. 创建这一工具的目标是 +减少不必要的编译或者任务.是传说中的 Stuart Feldman 在 1976 年花了一个周末写出来的, +而今仍然使用广泛, 特别是在 Unix 和 Linux 系统上. + +虽然每个语言可能都有相应的或多或少提供 make 的功能, 比如 ruby 的 rake, node 的 gulp, broccoli +, scala 的 sbt 等等. 但是 make 的简洁与高效, 和只做一件事并做到极致的风格, 使其至今仍是无可替代的, +甚至与其他构建工具一起使用也并无冲突. + +尽管有许多的分支和变体, 这篇文章针对是标准的 GNU make. + +```make +# 这行表示注释 + +# 文件名一定要交 Makefile, 大小写区分, 使用 `make <target>` 生成 target +# 如果想要取别的名字, 可以用 `make -f "filename" <target>`. + +# 重要的事情 - 只认识 TAB, 空格是不认的, 但是在 GNU Make 3.82 之后, 可以通过 +# 设置参数 .RECIPEPREFIX 进行修改 + +#----------------------------------------------------------------------- +# 初级 +#----------------------------------------------------------------------- + +# 创建一个 target 的规则非常简单 +# targets : prerequisites +# recipe +# … +# prerequisites(依赖) 是可选的, recipe(做法) 也可以多个或者不给. + +# 下面这个任务没有给 prerequisites, 只会在目标文件 file0.txt 文件不存在是跑 +file0.txt: + echo "foo" > file0.txt + # 试试 `make file0.txt` + # 或者直接 `make`, 因为第一个任务是默认任务. + # 注意: 即使是这些注释, 如果前面有 TAB, 也会发送给 shell, 注意看 `make file0.txt` 输出 + +# 如果提供 prerequisites, 则只有 prerequisites 比 target 新时会执行 +# 比如下面这个任务只有当 file1.txt 比 file0.txt 新时才会执行. +file1.txt: file0.txt + cat file0.txt > file1.txt + # 这里跟shell里的命令式一毛一样的. + @cat file0.txt >> file1.txt + # @ 不会把命令往 stdout 打印. + -@echo 'hello' + # - 意思是发生错误了也没关系. + # 试试 `make file1.txt` 吧. + +# targets 和 prerequisites 都可以是多个, 以空格分割 +file2.txt file3.txt: file0.txt file1.txt + touch file2.txt + touch file3.txt + +# 如果声明重复的 target, make 会给一个 warning, 后面会覆盖前面的 +# 比如重复定义 file2.txt 会得到这样的 warning +# Makefile:46: warning: overriding commands for target `file2.txt' +# Makefile:40: warning: ignoring old commands for target `file2.txt' +file2.txt: file0.txt + touch file2.txt + +# 但是如果不定义任何 recipe, 就不会冲突, 只是多了依赖关系 +file2.txt: file0.txt file3.txt + +#----------------------------------------------------------------------- +# Phony(假的) Targets +#----------------------------------------------------------------------- + +# phony targets 意思是 tagets 并不是文件, 可以想象成一个任务的名字而已. +# 因为不是文件, 无法比对是否有更新, 所以每次make都会执行. +all: maker process + +# 依赖于 phony target 的 target 也会每次 make 都执行, 即使 target 是文件 +ex0.txt ex1.txt: maker + +# target 的声明顺序并不重要, 比如上面的 all 的依赖 maker 现在才声明 +maker: + touch ex0.txt ex1.txt + +# 如果定义的 phony target 与文件名重名, 可以用 .PHONY 显示的指明哪些 targets 是 phony +.PHONY: all maker process +# This is a special target. There are several others. + +# 常用的 phony target 有: all clean install ... + +#----------------------------------------------------------------------- +# 变量与通配符 +#----------------------------------------------------------------------- + +process: file*.txt | dir/a.foo.b # 可以用通配符匹配多个文件作为prerequisites + @echo $^ # $^ 是 prerequisites + @echo $@ # $@ 代表 target, 如果 target 为多个, $@ 代表当前执行的那个 + @echo $< # $< prerequisite 中的第一个 + @echo $? # $? 需要更新的 prerequisite 文件列表 + @echo $+ # $+ 所有依赖, 包括重复的 + @echo $| # $| 竖线后面的 order-only prerequisites + +a.%.b: + @echo $* # $* match 的target % 那部分, 包括路径, 比如 `make dir/a.foo.b` 会打出 `dir/foo` + +# 即便分开定义依赖, $^ 依然能拿到 +process: ex1.txt file0.txt +# 非常智能的, ex1.txt 会被找到, file0.txt 会被去重. + +#----------------------------------------------------------------------- +# 模式匹配 +#----------------------------------------------------------------------- + +# 可以让 make 知道如何转换某些文件到别格式 +# 比如 从 svg 到 png +%.png: %.svg + inkscape --export-png $^ + +# 一旦有需要 foo.png 这个任务就会运行 + +# 路径会被忽略, 所以上面的 target 能匹配所有 png +# 但是如果加了路径, make 会找到最接近的匹配, 如果 +# make small/foo.png (在这之前要先有 small/foo.svg 这个文件) +# 则会匹配下面这个规则 +small/%.png: %.svg + inkscape --export-png --export-dpi 30 $^ + +%.png: %.svg + @echo 重复定义会覆盖前面的, 现在 inkscape 没用了 + +# make 已经有一些内置的规则, 比如从 *.c 到 *.o + +#----------------------------------------------------------------------- +# 变量 +#----------------------------------------------------------------------- +# 其实是宏 macro + +# 变量都是字符串类型, 下面这俩是一样一样的 + +name = Ted +name2="Sarah" + +echo: + @echo $(name) + @echo ${name2} + @echo $name # 这个会被蠢蠢的解析成 $(n)ame. + @echo \"$(name3)\" # 为声明的变量或扩展成空字符串. + @echo $(name4) + @echo $(name5) +# 你可以通过4种方式设置变量. +# 按以下顺序由高到低: +# 1: 命令行参数. 比如试试 `make echo name3=JICHAO` +# 2: Makefile 里面的 +# 3: shell 中的环境变量 +# 4: make 预设的一些变量 + +name4 ?= Jean +# 问号意思是如果 name4 被设置过了, 就不设置了. + +override name5 = David +# 用 override 可以防止命令行参数设置的覆盖 + +name4 +=grey +# 用加号可以连接 (中间用空格分割). + +# 在依赖的地方设置变量 +echo: name2 = Sara2 + +# 还有一些内置的变量 +echo_inbuilt: + echo $(CC) + echo ${CXX)} + echo $(FC) + echo ${CFLAGS)} + echo $(CPPFLAGS) + echo ${CXXFLAGS} + echo $(LDFLAGS) + echo ${LDLIBS} + +#----------------------------------------------------------------------- +# 变量 2 +#----------------------------------------------------------------------- + +# 加个冒号可以声明 Simply expanded variables 即时扩展变量, 即只在声明时扩展一次 +# 之前的等号声明时 recursively expanded 递归扩展 + +var := hello +var2 := $(var) hello + +# 这些变量会在其引用的顺序求值 +# 比如 var3 声明时找不到 var4, var3 会扩展成 `and good luck` +var3 := $(var4) and good luck +# 但是一般的变量会在调用时递归扩展, 先扩展 var5, 再扩展 var4, 所以是正常的 +var5 = $(var4) and good luck +var4 := good night + +echoSEV: + @echo $(var) + @echo $(var2) + @echo $(var3) + @echo $(var4) + @echo $(var5) + +#----------------------------------------------------------------------- +# 函数 +#----------------------------------------------------------------------- + +# make 自带了一些函数. +# wildcard 会将后面的通配符变成一串文件路径 +all_markdown: + @echo $(wildcard *.markdown) +# patsubst 可以做替换, 比如下面会把所有 markdown +# 后缀的文件重命名为 md 后缀 +substitue: * + @echo $(patsubst %.markdown,%.md,$* $^) + +# 函数调用格式是 $(func arg0,arg1,arg2...) + +# 试试 +ls: * + @echo $(filter %.txt, $^) + @echo $(notdir $^) + @echo $(join $(dir $^),$(notdir $^)) + +#----------------------------------------------------------------------- +# Directives +#----------------------------------------------------------------------- + +# 可以用 include 引入别的 Makefile 文件 +# include foo.mk + +sport = tennis +# 一些逻辑语句 if else 什么的, 顶个写 +report: +ifeq ($(sport),tennis) + @echo 'game, set, match' +else + @echo "They think it's all over; it is now" +endif + +# 还有 ifneq, ifdef, ifndef + +foo = true + +# 不只是 recipe, 还可以写在外面哟 +ifdef $(foo) +bar = 'bar' +endif + +hellobar: + @echo bar +``` + +### 资源 + ++ GNU Make 官方文档 [HTML](https://www.gnu.org/software/make/manual/) [PDF](https://www.gnu.org/software/make/manual/make.pdf) ++ [software carpentry tutorial](http://swcarpentry.github.io/make-novice/) ++ learn C the hard way [ex2](http://c.learncodethehardway.org/book/ex2.html) [ex28](http://c.learncodethehardway.org/book/ex28.html) diff --git a/zh-tw/pcre-tw.html.markdown b/zh-tw/pcre-tw.html.markdown new file mode 100644 index 00000000..c9cdc537 --- /dev/null +++ b/zh-tw/pcre-tw.html.markdown @@ -0,0 +1,83 @@ +--- +language: PCRE +filename: pcre-tw.txt +contributors: + - ["Sachin Divekar", "http://github.com/ssd532"] +translators: + - ["Michael Yeh", "https://hinet60613.github.io/"] +lang: zh-tw +--- + +正規表達式(regular expression，或縮寫為regex, regexp)是一種用來表示搜尋模式的特殊字串。例如，你可以用`/^[a-z]+:/`來從網址`http://github.com`中擷取出`http:`這段http協定名稱。 + +相容Perl正規表達式(Perl Compatible Regular Expressions, PCRE)是一個實作正規表達式的C語言函式庫。此函式庫在1997年被開發出來，在當時面對複雜字串處理時大多會選擇使用Perl。也因為如此，PCRE大多的正規表達式語法都很酷似Perl。PCRE語法被廣泛運用在許多大專案中，包括PHP、Apache、R等。 + +PCRE中的超字元(metacharacter)主要可以分為以下兩類: +* 在中括號外會被辨識的字元 +``` + \ 通用跳脫字元 + ^ 字串開頭 或 行首 + $ 字串結尾 或 行尾 + . 除了換行符號外的任何字元 + [ 字元集合定義開始 + | 支流開始 + ( 子串模式定義開始 + ) 子串模式定義結束 + ? extends the meaning of ( + 同時為數量0或1配對 + also quantifier minimizer + * 量詞 至少0個 至多無限個 + + 量詞 至少1個 至多無限個 + 同時為佔有型量詞 + { 最大/最小量詞開始 +``` + +* 在中括號內會被辨識的超字元，在中括號外會被視為字元集合使用 + +``` + + \ 通用跳脫字元 + ^ 非字元集合的字，但只會抓到第一個符合的字元 + - 字元範圍 + [ POSIX字元集合(若後面接POSIX格式) + ] 字元集合定義結束 + +``` + +PCRE提供了一些通用的字元類型，可被當作字元集合使用 +``` + \d 任何數字字元 + \D 任何非數字字元 + \h 任何水平空白字元 + \H 任何非水平空白字元 + \s 任何空白字元 + \S 任何非空白至元 + \v 任何垂直空白字元 + \V 任何非垂直空白字元 + \w 任何英文字 + \W 任何非英文字 +``` + +## 範例 + +我們以字串 `66.249.64.13 - - [18/Sep/2004:11:07:48 +1000] "GET /robots.txt HTTP/1.0" 200 468 "-" "Googlebot/2.1"` 作為範例，這是一個標準的Apache存取記錄。 + +| 正規表達式 | 結果 | 說明 | +| :---- | :-------------- | :------ | +| GET | GET | GET 抓取 GET 字串 (會分別大小寫) | +| \d+.\d+.\d+.\d+ | 66.249.64.13 | `\d+` 抓取數字字元，數量由 `+` 定義為至少一個至多無限個。 `\.` 抓取 `.` 字元 | +| (\d+\.){3}\d+ | 66.249.64.13 | `(\d+\.){3}` 會試著抓取剛好三次的 (`\d+\.`) | +| \[.+\] | [18/Sep/2004:11:07:48 +1000] | `.+` 抓取除了換行符號以外的任何字元， `.` 表示任意字元 | +| ^\S+ | 66.249.64.13 | `^` 為行首， `\S+` 抓取至少一個非空白字元 | +| \+[0-9]+ | +1000 | `\+` 抓取 `+` 字元。 `[0-9]` 字元集表示剛好一個數字字元。 可以用 `\+\d+` 達到相同效果。 | + +以上範例皆可在 https://regex101.com/ 測試，步驟如下: + +1. 複製範例字串到 `TEST STRING` 區域 +2. 複製正規表達式字串到 `Regular Expression` 區域 +3. 網頁會顯示自動表達式抓取結果 + + +## 更多資料 + + |