diff options
33 files changed, 2917 insertions, 320 deletions
diff --git a/README.markdown b/README.markdown index 4e24bbe6..774797d5 100644 --- a/README.markdown +++ b/README.markdown @@ -22,6 +22,11 @@ Send a pull request or open an issue any time of day or night. **(e.g. [python/en] for English Python).** This will help everyone pick out things they care about. +We're happy for any contribution in any form, but if you're making more than one major change +(i.e. translations for two different languages) it would be super cool of you to make a +separate pull request for each one so that someone can review them more effectively and/or +individually. + ### Style Guidelines * **Keep lines under 80 chars** diff --git a/c++.html.markdown b/c++.html.markdown index 9f357b08..5f80f26f 100644 --- a/c++.html.markdown +++ b/c++.html.markdown @@ -238,7 +238,10 @@ string& fooRef = foo; // This creates a reference to foo. fooRef += ". Hi!"; // Modifies foo through the reference cout << fooRef; // Prints "I am foo. Hi!" -fooRef = bar; // Error: references cannot be reassigned. +// Doesn't reassign "fooRef". This is the same as "foo = bar", and +// foo == "I am bar" +// after this line. +fooRef = bar; const string& barRef = bar; // Create a const reference to bar. // Like C, const values (and pointers and references) cannot be modified. diff --git a/c.html.markdown b/c.html.markdown index 874197d3..7670824a 100644 --- a/c.html.markdown +++ b/c.html.markdown @@ -26,13 +26,15 @@ Multi-line comments look like this. They work in C89 as well. Multi-line comments don't nest /* Be careful */ // comment ends on this line... */ // ...not this one! - // Constants: #define <keyword> +// Constants: #define <keyword> #define DAYS_IN_YEAR 365 - // Enumeration constants are also ways to declare constants. - enum days {SUN = 1, MON, TUE, WED, THU, FRI, SAT}; +// Enumeration constants are also ways to declare constants. +// All statements must end with a semicolon +enum days {SUN = 1, MON, TUE, WED, THU, FRI, SAT}; // MON gets 2 automatically, TUE gets 3, etc. + // Import headers with #include #include <stdlib.h> #include <stdio.h> @@ -57,7 +59,6 @@ int main() { // print output using printf, for "print formatted" // %d is an integer, \n is a newline printf("%d\n", 0); // => Prints 0 - // All statements must end with a semicolon /////////////////////////////////////// // Types @@ -385,7 +386,8 @@ int main() { // or when it's the argument of the `sizeof` or `alignof` operator: int arraythethird[10]; int *ptr = arraythethird; // equivalent with int *ptr = &arr[0]; - printf("%zu, %zu\n", sizeof arraythethird, sizeof ptr); // probably prints "40, 4" or "40, 8" + printf("%zu, %zu\n", sizeof arraythethird, sizeof ptr); + // probably prints "40, 4" or "40, 8" // Pointers are incremented and decremented based on their type @@ -476,7 +478,7 @@ void testFunc() { } //make external variables private to source file with static: -static int j = 0; //other files using testFunc() cannot access variable i +static int j = 0; //other files using testFunc2() cannot access variable j void testFunc2() { extern int j; } @@ -629,7 +631,7 @@ typedef void (*my_fnp_type)(char *); ## Further Reading Best to find yourself a copy of [K&R, aka "The C Programming Language"](https://en.wikipedia.org/wiki/The_C_Programming_Language) -It is *the* book about C, written by the creators of C. Be careful, though - it's ancient and it contains some +It is *the* book about C, written by Dennis Ritchie, the creator of C, and Brian Kernighan. Be careful, though - it's ancient and it contains some inaccuracies (well, ideas that are not considered good anymore) or now-changed practices. Another good resource is [Learn C the hard way](http://c.learncodethehardway.org/book/). diff --git a/csharp.html.markdown b/csharp.html.markdown index f6708590..47dd9683 100644 --- a/csharp.html.markdown +++ b/csharp.html.markdown @@ -678,6 +678,23 @@ on a new line! ""Wow!"", the masses cried"; private set; } + // It's also possible to define custom Indexers on objects. + // All though this is not entirely useful in this example, you + // could do bicycle[0] which yields "chris" to get the first passenger or + // bicycle[1] = "lisa" to set the passenger. (of this apparent quattrocycle) + private string[] passengers = { "chris", "phil", "darren", "regina" } + + public string this[int i] + { + get { + return passengers[i]; + } + + set { + return passengers[i] = value; + } + } + //Method to display the attribute values of this Object. public virtual string Info() { diff --git a/forth.html.markdown b/forth.html.markdown new file mode 100644 index 00000000..f7c0bf34 --- /dev/null +++ b/forth.html.markdown @@ -0,0 +1,225 @@ +--- +language: forth +contributors: + - ["Horse M.D.", "http://github.com/HorseMD/"] +filename: learnforth.fs +--- + +Forth was created by Charles H. Moore in the 70s. It is an imperative, +stack-based language and programming environment, being used in projects +such as Open Firmware. It's also used by NASA. + +Note: This article focuses predominantly on the Gforth implementation of +Forth, but most of what is written here should work elsewhere. + +``` +\ This is a comment +( This is also a comment but it's only used when defining words ) + +\ --------------------------------- Precursor ---------------------------------- + +\ All programming in Forth is done by manipulating the parameter stack (more +\ commonly just referred to as "the stack"). +5 2 3 56 76 23 65 \ ok + +\ Those numbers get added to the stack, from left to right. +.s \ <7> 5 2 3 56 76 23 65 ok + +\ In Forth, everything is either a word or a number. + +\ ------------------------------ Basic Arithmetic ------------------------------ + +\ Arithmetic (in fact most words requiring data) works by manipulating data on +\ the stack. +5 4 + \ ok + +\ `.` pops the top result from the stack: +. \ 9 ok + +\ More examples of arithmetic: +6 7 * . \ 42 ok +1360 23 - . \ 1337 ok +12 12 / . \ 1 ok +13 2 mod . \ 1 ok + +99 negate . \ -99 ok +-99 abs . \ 99 ok +52 23 max . \ 52 ok +52 23 min . \ 23 ok + +\ ----------------------------- Stack Manipulation ----------------------------- + +\ Naturally, as we work with the stack, we'll want some useful methods: + +3 dup - \ duplicate the top item (1st now equals 2nd): 3 - 3 +2 5 swap / \ swap the top with the second element: 5 / 2 +6 4 5 rot .s \ rotate the top 3 elements: 4 5 6 +4 0 drop 2 / \ remove the top item (dont print to screen): 4 / 2 +1 2 3 nip .s \ remove the second item (similar to drop): 1 3 + +\ ---------------------- More Advanced Stack Manipulation ---------------------- + +1 2 3 4 tuck \ duplicate the top item into the second slot: 1 2 4 3 4 ok +1 2 3 4 over \ duplicate the second item to the top: 1 2 3 4 3 ok +1 2 3 4 2 roll \ *move* the item at that position to the top: 1 3 4 2 ok +1 2 3 4 2 pick \ *duplicate* the item at that position to the top: 1 2 3 4 2 ok + +\ When referring to stack indexes, they are zero-based. + +\ ------------------------------ Creating Words -------------------------------- + +\ The `:` word sets Forth into compile mode until it sees the `;` word. +: square ( n -- n ) dup * ; \ ok +5 square . \ 25 ok + +\ We can view what a word does too: +see square \ : square dup * ; ok + +\ -------------------------------- Conditionals -------------------------------- + +\ -1 == true, 0 == false. However, any non-zero value is usually treated as +\ being true: +42 42 = \ -1 ok +12 53 = \ 0 ok + +\ `if` is a compile-only word. `if` <stuff to do> `then` <rest of program>. +: ?>64 ( n -- n ) dup 64 > if ." Greater than 64!" then ; \ ok +100 ?>64 \ Greater than 64! ok + +\ Else: +: ?>64 ( n -- n ) dup 64 > if ." Greater than 64!" else ." Less than 64!" then ; +100 ?>64 \ Greater than 64! ok +20 ?>64 \ Less than 64! ok + +\ ------------------------------------ Loops ----------------------------------- + +\ `do` is also a compile-only word. +: myloop ( -- ) 5 0 do cr ." Hello!" loop ; \ ok +myloop +\ Hello! +\ Hello! +\ Hello! +\ Hello! +\ Hello! ok + +\ `do` expects two numbers on the stack: the end number and the start number. + +\ We can get the value of the index as we loop with `i`: +: one-to-12 ( -- ) 12 0 do i . loop ; \ ok +one-to-12 \ 0 1 2 3 4 5 6 7 8 9 10 11 12 ok + +\ `?do` works similarly, except it will skip the loop if the end and start +\ numbers are equal. +: squares ( n -- ) 0 ?do i square . loop ; \ ok +10 squares \ 0 1 4 9 16 25 36 49 64 81 ok + +\ Change the "step" with `+loop`: +: threes ( n n -- ) ?do i . 3 +loop ; \ ok +15 0 threes \ 0 3 6 9 12 ok + +\ Indefinite loops with `begin` <stuff to do> <flag> `unil`: +: death ( -- ) begin ." Are we there yet?" 0 until ; \ ok + +\ ---------------------------- Variables and Memory ---------------------------- + +\ Use `variable` to declare `age` to be a variable. +variable age \ ok + +\ Then we write 21 to age with the word `!`. +21 age ! \ ok + +\ Finally we can print our variable using the "read" word `@`, which adds the +\ value to the stack, or use `?` that reads and prints it in one go. +age @ . \ 21 ok +age ? \ 21 ok + +\ Constants are quite simiar, except we don't bother with memory addresses: +100 constant WATER-BOILING-POINT \ ok +WATER-BOILING-POINT . \ 100 ok + +\ ----------------------------------- Arrays ----------------------------------- + +\ Creating arrays is similar to variables, except we need to allocate more +\ memory to them. + +\ You can use `2 cells allot` to create an array that's 3 cells long: +variable mynumbers 2 cells allot \ ok + +\ Initialize all the values to 0 +mynumbers 3 cells erase \ ok + +\ Alternatively we could use `fill`: +mynumbers 3 cells 0 fill + +\ or we can just skip all the above and initialize with specific values: +create mynumbers 64 , 9001 , 1337 , \ ok (the last `,` is important!) + +\ ...which is equivalent to: + +\ Manually writing values to each index: +64 mynumbers 0 cells + ! \ ok +9001 mynumbers 1 cells + ! \ ok +1337 mynumbers 2 cells + ! \ ok + +\ Reading values at certain array indexes: +0 cells mynumbers + ? \ 64 ok +1 cells mynumbers + ? \ 9001 ok + +\ We can simplify it a little by making a helper word for manipulating arrays: +: of-arr ( n n -- n ) cells + ; \ ok +mynumbers 2 of-arr ? \ 1337 ok + +\ Which we can use for writing too: +20 mynumbers 1 of-arr ! \ ok +mynumbers 1 of-arr ? \ 20 ok + +\ ------------------------------ The Return Stack ------------------------------ + +\ The return stack is used to the hold pointers to things when words are +\ executing other words, e.g. loops. + +\ We've already seen one use of it: `i`, which duplicates the top of the return +\ stack. `i` is equivalent to `r@`. +: myloop ( -- ) 5 0 do r@ . loop ; \ ok + +\ As well as reading, we can add to the return stack and remove from it: +5 6 4 >r swap r> .s \ 6 5 4 ok + +\ NOTE: Because Forth uses the return stack for word pointers, `>r` should +\ always be followed by `r>`. + +\ ------------------------- Floating Point Operations -------------------------- + +\ Most Forths tend to eschew the use of floating point operations. +8.3e 0.8e f+ f. \ 9.1 ok + +\ Usually we simply prepend words with 'f' when dealing with floats: +variable myfloatingvar \ ok +4.4e myfloatingvar f! \ ok +myfloatingvar f@ f. \ 4.4 ok + +\ --------------------------------- Final Notes -------------------------------- + +\ Typing a non-existent word will empty the stack. However, there's also a word +\ specifically for that: +clearstack + +\ Clear the screen: +page + +\ Loading Forth files: +\ s" forthfile.fs" included + +\ You can list every word that's in Forth's dictionary (but it's a huge list!): +\ words + +\ Exiting Gforth: +\ bye + +``` + +##Ready For More? + +* [Starting Forth](http://www.forth.com/starting-forth/) +* [Simple Forth](http://www.murphywong.net/hello/simple.htm) +* [Thinking Forth](http://thinking-forth.sourceforge.net/) diff --git a/fr-fr/brainfuck-fr.html.markdown b/fr-fr/brainfuck-fr.html.markdown index 3882734d..545e407e 100644 --- a/fr-fr/brainfuck-fr.html.markdown +++ b/fr-fr/brainfuck-fr.html.markdown @@ -13,7 +13,7 @@ Brainfuck (sans majuscule à part au début d’une phrase) est un langage Turing-complet extrêmement simple avec seulement 8 commandes. ``` -Tout caractère en dehors de "><+-.,[]" (en dehors des guillements) est ignoré. +Tout caractère en dehors de "><+-.,[]" (en dehors des guillemets) est ignoré. Brainfuck est représenté par un tableau de 30 000 cellules initialisées à 0 et un pointeur de données pointant sur la cellule courante. diff --git a/fr-fr/ruby-fr.html.markdown b/fr-fr/ruby-fr.html.markdown index 75c8d0d3..1564d2b6 100644 --- a/fr-fr/ruby-fr.html.markdown +++ b/fr-fr/ruby-fr.html.markdown @@ -268,7 +268,7 @@ end # implicitement la valeur de la dernière instruction évaluée double(2) #=> 4 -# Les paranthèses sont facultative +# Les parenthèses sont facultatives # lorsqu'il n'y a pas d'ambiguïté sur le résultat double 3 #=> 6 diff --git a/fr-fr/yaml-fr.html.markdown b/fr-fr/yaml-fr.html.markdown index d9b94aa6..43b1df54 100644 --- a/fr-fr/yaml-fr.html.markdown +++ b/fr-fr/yaml-fr.html.markdown @@ -3,6 +3,7 @@ language: yaml filename: learnyaml.yaml contributors: - ["Andrei Curelaru", "http://www.infinidad.fr"] +lang: fr-fr --- Proposé à l'origine par Clark Evans en Mai 2001, YAML est un un format de @@ -153,4 +154,4 @@ Quelques références et outils : - Doc officielle [YAML 1.2](http://www.yaml.org/spec/1.2/spec.html) *anglais*, - Une [Introduction à YAML](http://sweetohm.net/html/introduction-yaml.html) très bien construite et claire, -- Un outil pour tester [live](http://yaml-online-parser.appspot.com/) la syntaxe YAML, avec des exemples.
\ No newline at end of file +- Un outil pour tester [live](http://yaml-online-parser.appspot.com/) la syntaxe YAML, avec des exemples. diff --git a/git.html.markdown b/git.html.markdown index 618d1906..04350dd5 100644 --- a/git.html.markdown +++ b/git.html.markdown @@ -3,6 +3,8 @@ category: tool tool: git contributors: - ["Jake Prather", "http://github.com/JakeHP"] + - ["Leo Rudberg" , "http://github.com/LOZORD"] + - ["Betsy Lorton" , "http://github.com/schbetsy"] filename: LearnGit.txt --- @@ -334,6 +336,66 @@ $ git push -u origin master $ git push ``` +### stash + +Stashing takes the dirty state of your working directory and saves it on a stack of unfinished changes that you can reapply at any time. + +Let's say you've been doing some work in your git repo, but you want to pull from the remote. +Since you have dirty (uncommited) changes to some files, you are not able to run `git pull`. +Instead, you can run `git stash` to save your changes onto a stack! + +```bash +$ git stash +Saved working directory and index state \ + "WIP on master: 049d078 added the index file" + HEAD is now at 049d078 added the index file + (To restore them type "git stash apply") +``` + +Now you can pull! + +```bash +git pull +``` +`...changes apply...` + +Now check that everything is OK + +```bash +$ git status +# On branch master +nothing to commit, working directory clean +``` + +You can see what "hunks" you've stashed so far using `git stash list`. +Since the "hunks" are stored in a Last-In-First-Out stack, our most recent change will be at top. + +```bash +$ git stash list +stash@{0}: WIP on master: 049d078 added the index file +stash@{1}: WIP on master: c264051 Revert "added file_size" +stash@{2}: WIP on master: 21d80a5 added number to log +``` + +Now let's apply our dirty changes back by popping them off the stack. + +```bash +$ git stash pop +# On branch master +# Changes not staged for commit: +# (use "git add <file>..." to update what will be committed) +# +# modified: index.html +# modified: lib/simplegit.rb +# +``` + +`git stash apply` does the same thing + +Now you're ready to get back to work on your stuff! + +[Additional Reading.](http://git-scm.com/book/en/v1/Git-Tools-Stashing) + ### rebase (caution) Take all changes that were committed on one branch, and replay them onto another branch. @@ -396,4 +458,4 @@ $ git rm /pather/to/the/file/HelloWorld.c * [GitGuys](http://www.gitguys.com/) -* [Git - the simple guide](http://rogerdudler.github.io/git-guide/index.html)
\ No newline at end of file +* [Git - the simple guide](http://rogerdudler.github.io/git-guide/index.html) diff --git a/haskell.html.markdown b/haskell.html.markdown index 2785405c..748a29da 100644 --- a/haskell.html.markdown +++ b/haskell.html.markdown @@ -110,7 +110,7 @@ last [1..5] -- 5 -- A tuple: ("haskell", 1) --- accessing elements of a tuple +-- accessing elements of a pair (i.e. a tuple of length 2) fst ("haskell", 1) -- "haskell" snd ("haskell", 1) -- 1 @@ -195,8 +195,8 @@ foo 5 -- 75 -- fixing precedence -- Haskell has another function called `$`. This changes the precedence -- so that everything to the left of it gets computed first and then applied --- to everything on the right. You can use `.` and `$` to get rid of a lot --- of parentheses: +-- to everything on the right. You can use `$` (often in combination with `.`) +-- to get rid of a lot of parentheses: -- before (even (fib 7)) -- true @@ -204,6 +204,9 @@ foo 5 -- 75 -- after even . fib $ 7 -- true +-- equivalently +even $ fib 7 -- true + ---------------------------------------------------- -- 5. Type signatures ---------------------------------------------------- @@ -227,24 +230,24 @@ double :: Integer -> Integer double x = x * 2 ---------------------------------------------------- --- 6. Control Flow and If Statements +-- 6. Control Flow and If Expressions ---------------------------------------------------- --- if statements +-- if expressions haskell = if 1 == 1 then "awesome" else "awful" -- haskell = "awesome" --- if statements can be on multiple lines too, indentation is important +-- if expressions can be on multiple lines too, indentation is important haskell = if 1 == 1 then "awesome" else "awful" --- case statements: Here's how you could parse command line arguments +-- case expressions: Here's how you could parse command line arguments case args of "help" -> printHelp "start" -> startProgram _ -> putStrLn "bad args" --- Haskell doesn't have loops because it uses recursion instead. +-- Haskell doesn't have loops; it uses recursion instead. -- map applies a function over every element in an array map (*2) [1..5] -- [2, 4, 6, 8, 10] diff --git a/haxe.html.markdown b/haxe.html.markdown index 6a868f09..8599de8d 100644 --- a/haxe.html.markdown +++ b/haxe.html.markdown @@ -484,7 +484,7 @@ class LearnHaxe3{ // we can read this variable trace(foo_instance.public_read + " is the value for foo_instance.public_read"); // but not write it - // foo_instance.public_write = 4; // this will throw an error if uncommented: + // foo_instance.public_read = 4; // this will throw an error if uncommented: // trace(foo_instance.public_write); // as will this. trace(foo_instance + " is the value for foo_instance"); // calls the toString method diff --git a/hy.html.markdown b/hy.html.markdown index 04bd05c9..9beaff0c 100644 --- a/hy.html.markdown +++ b/hy.html.markdown @@ -83,7 +83,7 @@ True ; => True (greet "bilbo") ;=> "hello bilbo" ; functions can take optional arguments as well as keyword arguments -(defn foolist [arg1 &optional [arg2 2]] +(defn foolists [arg1 &optional [arg2 2]] [arg1 arg2]) (foolists 3) ;=> [3 2] diff --git a/java.html.markdown b/java.html.markdown index f08c4679..3dd65679 100644 --- a/java.html.markdown +++ b/java.html.markdown @@ -4,6 +4,7 @@ language: java contributors: - ["Jake Prather", "http://github.com/JakeHP"] - ["Madison Dickson", "http://github.com/mix3d"] + - ["Jakukyo Friel", "http://weakish.github.io"] filename: LearnJava.java --- @@ -49,7 +50,7 @@ public class LearnJava { // Types & Variables /////////////////////////////////////// - // Declare a variable using <type> <name> [ + // Declare a variable using <type> <name> // Byte - 8-bit signed two's complement integer // (-128 <= byte <= 127) byte fooByte = 100; @@ -268,9 +269,9 @@ public class LearnJava { System.out.println(bar); // Prints A, because the statement is true - /////////////////////////////////////// - // Converting Data Types And Typcasting - /////////////////////////////////////// + //////////////////////////////////////// + // Converting Data Types And Typecasting + //////////////////////////////////////// // Converting data @@ -433,10 +434,12 @@ public interface Digestible { //We can now create a class that implements both of these interfaces public class Fruit implements Edible, Digestible { + @Override public void eat() { //... } + @Override public void digest() { //... } @@ -445,10 +448,12 @@ public class Fruit implements Edible, Digestible { //In java, you can extend only one class, but you can implement many interfaces. //For example: public class ExampleClass extends ExampleClassParent implements InterfaceOne, InterfaceTwo { + @Override public void InterfaceOneMethod() { } + @Override public void InterfaceTwoMethod() { } diff --git a/livescript.html.markdown b/livescript.html.markdown index 429b91cb..e64f7719 100644 --- a/livescript.html.markdown +++ b/livescript.html.markdown @@ -219,8 +219,8 @@ identity 1 # => 1 # Operators are not functions in LiveScript, but you can easily turn # them into one! Enter the operator sectioning: -divide-by-2 = (/ 2) -[2, 4, 8, 16].map(divide-by-2) .reduce (+) +divide-by-two = (/ 2) +[2, 4, 8, 16].map(divide-by-two) .reduce (+) # Not only of function application lives LiveScript, as in any good @@ -248,8 +248,8 @@ reduce = (f, xs, initial) --> xs.reduce f, initial # The underscore is also used in regular partial application, which you # can use for any function: div = (left, right) -> left / right -div-by-2 = div _, 2 -div-by-2 4 # => 2 +div-by-two = div _, 2 +div-by-two 4 # => 2 # Last, but not least, LiveScript has back-calls, which might help diff --git a/matlab.html.markdown b/matlab.html.markdown index 2b9077d5..9de41275 100644 --- a/matlab.html.markdown +++ b/matlab.html.markdown @@ -200,7 +200,7 @@ A(1, :) =[] % Delete the first row of the matrix A(:, 1) =[] % Delete the first column of the matrix transpose(A) % Transpose the matrix, which is the same as: -A' +A one ctranspose(A) % Hermitian transpose the matrix % (the transpose, followed by taking complex conjugate of each element) diff --git a/perl6.html.markdown b/perl6.html.markdown index 9f3a03ba..13f383fe 100644 --- a/perl6.html.markdown +++ b/perl6.html.markdown @@ -35,7 +35,8 @@ my $variable; ## * Scalars. They represent a single value. They start with a `$` my $str = 'String'; -my $str2 = "String"; # double quotes allow for interpolation +# double quotes allow for interpolation (which we'll see later): +my $str2 = "String"; # variable names can contain but not end with simple quotes and dashes, # and can contain (and end with) underscores : @@ -66,23 +67,13 @@ my @keys = 0, 2; @array[@keys] = @letters; # Assign using an array say @array; #=> a 6 b -# There are two more kinds of lists: Parcel and Arrays. -# Parcels are immutable lists (you can't modify a list that's not assigned). -# This is a parcel: -(1, 2, 3); # Not assigned to anything. Changing an element would provoke an error -# This is a list: -my @a = (1, 2, 3); # Assigned to `@a`. Changing elements is okay! - -# Lists flatten (in list context). You'll see below how to apply item context -# or use arrays to have real nested lists. - - -## * Hashes. Key-Value Pairs. -# Hashes are actually arrays of Pairs (`Key => Value`), -# except they get "flattened", removing duplicated keys. +## * Hashes, or key-value Pairs. +# Hashes are actually arrays of Pairs +# (you can construct a Pair object using the syntax `Key => Value`), +# except they get "flattened" (hash context), removing duplicated keys. my %hash = 1 => 2, 3 => 4; -my %hash = autoquoted => "key", # keys *can* get auto-quoted +my %hash = autoquoted => "key", # keys get auto-quoted "some other" => "value", # trailing commas are okay ; my %hash = <key1 value1 key2 value2>; # you can also create a hash @@ -112,30 +103,6 @@ sub say-hello-to(Str $name) { # You can provide the type of an argument say "Hello, $name !"; } -# Since you can omit parenthesis to call a function with no arguments, -# you need "&" in the name to capture `say-hello`. -my &s = &say-hello; -my &other-s = sub { say "Anonymous function !" } - -# A sub can have a "slurpy" parameter, or "doesn't-matter-how-many" -sub as-many($head, *@rest) { # `*@` (slurpy) will basically "take everything else". - # Note: you can have parameters *before* (like here) - # a slurpy one, but not *after*. - say @rest.join(' / ') ~ " !"; -} -say as-many('Happy', 'Happy', 'Birthday'); #=> Happy / Birthday ! - # Note that the splat did not consume - # the parameter before. - -## You can call a function with an array using the -# "argument list flattening" operator `|` -# (it's not actually the only role of this operator, but it's one of them) -sub concat3($a, $b, $c) { - say "$a, $b, $c"; -} -concat3(|@array); #=> a, b, c - # `@array` got "flattened" as a part of the argument list - ## It can also have optional arguments: sub with-optional($arg?) { # the "?" marks the argument optional say "I might return `(Any)` if I don't have an argument passed, @@ -154,23 +121,20 @@ hello-to; #=> Hello, World ! hello-to(); #=> Hello, World ! hello-to('You'); #=> Hello, You ! -## You can also, by using a syntax akin to the one of hashes (yay unification !), +## You can also, by using a syntax akin to the one of hashes (yay unified syntax !), ## pass *named* arguments to a `sub`. +# They're optional, and will default to "Any" (Perl's "null"-like value). sub with-named($normal-arg, :$named) { say $normal-arg + $named; } with-named(1, named => 6); #=> 7 # There's one gotcha to be aware of, here: # If you quote your key, Perl 6 won't be able to see it at compile time, -# and you'll have a single Pair object as a positional paramater. +# and you'll have a single Pair object as a positional paramater, +# which means this fails: +with-named(1, 'named' => 6); with-named(2, :named(5)); #=> 7 -with-named(3, :4named); #=> 7 - # (special colon pair syntax for numbers, - # to be used with s// and such, see later) - -with-named(3); # warns, because we tried to use the undefined $named in a `+`: - # by default, named arguments are *optional* # To make a named argument mandatory, you can use `?`'s inverse, `!` sub with-mandatory-named(:$str!) { @@ -187,11 +151,6 @@ sub takes-a-bool($name, :$bool) { # ... you can use the same "short boolean" hash syntax: takes-a-bool('config', :bool); # config takes True takes-a-bool('config', :!bool); # config takes False -# or you can use the "adverb" form: -takes-a-bool('config'):bool; #=> config takes True -takes-a-bool('config'):!bool; #=> config takes False -# You'll learn to love (or maybe hate, eh) that syntax later. - ## You can also provide your named arguments with defaults: sub named-def(:$def = 5) { @@ -201,8 +160,29 @@ named-def; #=> 5 named-def(:10def); #=> 10 named-def(def => 15); #=> 15 -# -- Note: we're going to learn *more* on subs really soon, -# but we need to grasp a few more things to understand their real power. Ready? +# Since you can omit parenthesis to call a function with no arguments, +# you need "&" in the name to capture `say-hello`. +my &s = &say-hello; +my &other-s = sub { say "Anonymous function !" } + +# A sub can have a "slurpy" parameter, or "doesn't-matter-how-many" +sub as-many($head, *@rest) { # `*@` (slurpy) will basically "take everything else". + # Note: you can have parameters *before* (like here) + # a slurpy one, but not *after*. + say @rest.join(' / ') ~ " !"; +} +say as-many('Happy', 'Happy', 'Birthday'); #=> Happy / Birthday ! + # Note that the splat did not consume + # the parameter before. + +## You can call a function with an array using the +# "argument list flattening" operator `|` +# (it's not actually the only role of this operator, but it's one of them) +sub concat3($a, $b, $c) { + say "$a, $b, $c"; +} +concat3(|@array); #=> a, b, c + # `@array` got "flattened" as a part of the argument list ### Containers # In Perl 6, values are actually stored in "containers". @@ -220,23 +200,19 @@ sub mutate($n is rw) { # A sub itself returns a container, which means it can be marked as rw: my $x = 42; -sub mod() is rw { $x } -mod() = 52; # in this case, the parentheses are mandatory - # (else Perl 6 thinks `mod` is a "term") +sub x-store() is rw { $x } +x-store() = 52; # in this case, the parentheses are mandatory + # (else Perl 6 thinks `mod` is an identifier) say $x; #=> 52 ### Control Flow Structures - -# You don't need to put parenthesis around the condition, -# but that also means you always have to use brackets (`{ }`) for their body: - ## Conditionals # - `if` # Before talking about `if`, we need to know which values are "Truthy" # (represent True), and which are "Falsey" (or "Falsy") -- represent False. -# Only these values are Falsey: (), 0, "0", Nil, A type (like `Str` or `Int`), +# Only these values are Falsey: (), 0, "0", "", Nil, A type (like `Str` or `Int`), # and of course False itself. # Every other value is Truthy. if True { @@ -247,30 +223,38 @@ unless False { say "It's not false !"; } +# As you can see, you don't need parentheses around conditions. +# However, you do need the brackets around the "body" block: +# if (true) say; # This doesn't work ! + # You can also use their postfix versions, with the keyword after: say "Quite truthy" if True; -# if (true) say; # This doesn't work ! - # - Ternary conditional, "?? !!" (like `x ? y : z` in some other languages) my $a = $condition ?? $value-if-true !! $value-if-false; # - `given`-`when` looks like other languages `switch`, but much more # powerful thanks to smart matching and thanks to Perl 6's "topic variable", $_. +# # This variable contains the default argument of a block, # a loop's current iteration (unless explicitly named), etc. +# # `given` simply puts its argument into `$_` (like a block would do), # and `when` compares it using the "smart matching" (`~~`) operator. +# # Since other Perl 6 constructs use this variable (as said before, like `for`, # blocks, etc), this means the powerful `when` is not only applicable along with # a `given`, but instead anywhere a `$_` exists. given "foo bar" { - when /foo/ { # Don't worry about smart matching -- just know `when` uses it. + say $_; #=> foo bar + when /foo/ { # Don't worry about smart matching yet – just know `when` uses it. # This is equivalent to `if $_ ~~ /foo/`. say "Yay !"; } when $_.chars > 50 { # smart matching anything with True (`$a ~~ True`) is True, # so you can also put "normal" conditionals. + # This when is equivalent to this `if`: + # if ($_.chars > 50) ~~ True {...} say "Quite a long string !"; } default { # same as `when *` (using the Whatever Star) @@ -281,7 +265,7 @@ given "foo bar" { ## Looping constructs # - `loop` is an infinite loop if you don't pass it arguments, -# but can also be a c-style `for`: +# but can also be a C-style `for` loop: loop { say "This is an infinite loop !"; last; # last breaks out of the loop, like the `break` keyword in other languages @@ -296,7 +280,7 @@ loop (my $i = 0; $i < 5; $i++) { # - `for` - Passes through an array for @array -> $variable { - say "I've found $variable !"; + say "I've got $variable !"; } # As we saw with given, for's default "current iteration" variable is `$_`. @@ -316,22 +300,15 @@ for @array { last if $_ == 5; # Or break out of a loop (like `break` in C-like languages). } -# Note - the "lambda" `->` syntax isn't reserved to `for`: +# The "pointy block" syntax isn't specific to for. +# It's just a way to express a block in Perl6. if long-computation() -> $result { say "The result is $result"; } -## Loops can also have a label, and be jumped to through these. -OUTER: while 1 { - say "hey"; - while 1 { - OUTER.last; # All the control keywords must be called on the label itself - } -} - # Now that you've seen how to traverse a list, you need to be aware of something: # List context (@) flattens. If you traverse nested lists, you'll actually be traversing a -# shallow list (except if some sub-list were put in item context ($)). +# shallow list. for 1, 2, (3, (4, ((5)))) { say "Got $_."; } #=> Got 1. Got 2. Got 3. Got 4. Got 5. @@ -348,9 +325,14 @@ for [1, 2, 3, 4] { say "Got $_."; } #=> Got 1 2 3 4. -# The other difference between `$()` and `[]` is that `[]` always returns a mutable Array -# whereas `$()` will return a Parcel when given a Parcel. +# You need to be aware of when flattening happens exactly. +# The general guideline is that argument lists flatten, but not method calls. +# Also note that `.list` and array assignment flatten (`@ary = ...`) flatten. +((1,2), 3, (4,5)).map({...}); # iterates over three elements (method call) +map {...}, ((1,2),3,(4,5)); # iterates over five elements (argument list is flattened) +(@a, @b, @c).pick(1); # picks one of three arrays (method call) +pick 1, @a, @b, @c; # flattens argument list and pick one element ### Operators @@ -394,9 +376,6 @@ $arg ~~ &bool-returning-function; # `True` if the function, passed `$arg` 1 ~~ True; # smart-matching against a boolean always returns that boolean # (and will warn). -# - `===` is value identity and uses `.WHICH` on the objects to compare them -# - `=:=` is container identity and uses `VAR()` on the objects to compare them - # You also, of course, have `<`, `<=`, `>`, `>=`. # Their string equivalent are also avaiable : `lt`, `le`, `gt`, `ge`. 3 > 4; @@ -559,6 +538,21 @@ map(sub ($a, $b) { $a + $b + 3 }, @array); # (here with `sub`) # Note : those are sorted lexicographically. # `{ $^b / $^a }` is like `-> $a, $b { $b / $a }` +## About types... +# Perl6 is gradually typed. This means you can specify the type +# of your variables/arguments/return types, or you can omit them +# and they'll default to "Any". +# You obviously get access to a few base types, like Int and Str. +# The constructs for declaring types are "class", "role", +# which you'll see later. + +# For now, let us examinate "subset": +# a "subset" is a "sub-type" with additional checks. +# For example: "a very big integer is an Int that's greater than 500" +# You can specify the type you're subtyping (by default, Any), +# and add additional checks with the "where" keyword: +subset VeryBigInteger of Int where * > 500; + ## Multiple Dispatch # Perl 6 can decide which variant of a `sub` to call based on the type of the # arguments, or on arbitrary preconditions, like with a type or a `where`: @@ -567,20 +561,19 @@ map(sub ($a, $b) { $a + $b + 3 }, @array); # (here with `sub`) multi sub sayit(Int $n) { # note the `multi` keyword here say "Number: $n"; } -multi sayit(Str $s) } # the `sub` is the default +multi sayit(Str $s) } # a multi is a `sub` by default say "String: $s"; } sayit("foo"); # prints "String: foo" sayit(True); # fails at *compile time* with # "calling 'sayit' will never work with arguments of types ..." -# with arbitrary precondition: +# with arbitrary precondition (remember subsets?): multi is-big(Int $n where * > 50) { "Yes !" } # using a closure multi is-big(Int $ where 10..50) { "Quite." } # Using smart-matching # (could use a regexp, etc) multi is-big(Int $) { "No" } -# You can also name these checks, by creating "subsets": subset Even of Int where * %% 2; multi odd-or-even(Even) { "Even" } # The main case using the type. @@ -724,7 +717,7 @@ role PrintableVal { } } -# you "use" a mixin with "does" : +# you "import" a mixin (a "role") with "does": class Item does PrintableVal { has $.val; @@ -1083,9 +1076,7 @@ postcircumfix:<{ }>(%h, $key, :delete); # (you can call operators like that) # It's a prefix meta-operator that takes a binary functions and # one or many lists. If it doesn't get passed any argument, # it either return a "default value" for this operator -# (a value that wouldn't change the result if passed as one -# of the element of the list to be passed to the operator), -# or `Any` if there's none (examples below). +# (a meaningless value) or `Any` if there's none (examples below). # # Otherwise, it pops an element from the list(s) one at a time, and applies # the binary function to the last result (or the list's first element) @@ -1107,9 +1098,7 @@ say [//] Nil, Any, False, 1, 5; #=> False # Default value examples: say [*] (); #=> 1 say [+] (); #=> 0 - # In both cases, they're results that, were they in the lists, - # wouldn't have any impact on the final value - # (since N*1=N and N+0=N). + # meaningless values, since N*1=N and N+0=N. say [//]; #=> (Any) # There's no "default value" for `//`. @@ -1163,90 +1152,6 @@ say @fib[^10]; #=> 1 1 2 3 5 8 13 21 34 55 # That's why `@primes[^100]` will take a long time the first time you print # it, then be instant. - -## * Sort comparison -# They return one value of the `Order` enum : `Less`, `Same` and `More` -# (which numerify to -1, 0 or +1). -1 <=> 4; # sort comparison for numerics -'a' leg 'b'; # sort comparison for string -$obj eqv $obj2; # sort comparison using eqv semantics - -## * Generic ordering -3 before 4; # True -'b' after 'a'; # True - -## * Short-circuit default operator -# Like `or` and `||`, but instead returns the first *defined* value : -say Any // Nil // 0 // 5; #=> 5 - -## * Short-circuit exclusive or (XOR) -# Returns `True` if one (and only one) of its arguments is true -say True ^^ False; #=> True - -## * Flip Flop -# The flip flop operators (`ff` and `fff`, equivalent to P5's `..`/`...`). -# are operators that take two predicates to test: -# They are `False` until their left side returns `True`, then are `True` until -# their right side returns `True`. -# Like for ranges, you can exclude the iteration when it became `True`/`False` -# by using `^` on either side. -# Let's start with an example : -for <well met young hero we shall meet later> { - # by default, `ff`/`fff` smart-match (`~~`) against `$_`: - if 'met' ^ff 'meet' { # Won't enter the if for "met" - # (explained in details below). - .say - } - - if rand == 0 ff rand == 1 { # compare variables other than `$_` - say "This ... probably will never run ..."; - } -} -# This will print "young hero we shall meet" (excluding "met"): -# the flip-flop will start returning `True` when it first encounters "met" -# (but will still return `False` for "met" itself, due to the leading `^` -# on `ff`), until it sees "meet", which is when it'll start returning `False`. - -# The difference between `ff` (awk-style) and `fff` (sed-style) is that -# `ff` will test its right side right when its left side changes to `True`, -# and can get back to `False` right away -# (*except* it'll be `True` for the iteration that matched) - -# While `fff` will wait for the next iteration to -# try its right side, once its left side changed: -.say if 'B' ff 'B' for <A B C B A>; #=> B B - # because the right-hand-side was tested - # directly (and returned `True`). - # "B"s are printed since it matched that time - # (it just went back to `False` right away). -.say if 'B' fff 'B' for <A B C B A>; #=> B C B - # The right-hand-side wasn't tested until - # `$_` became "C" - # (and thus did not match instantly). - -# A flip-flop can change state as many times as needed: -for <test start print it stop not printing start print again stop not anymore> { - .say if $_ eq 'start' ^ff^ $_ eq 'stop'; # exclude both "start" and "stop", - #=> "print this printing again" -} - -# you might also use a Whatever Star, -# which is equivalent to `True` for the left side or `False` for the right: -for (1, 3, 60, 3, 40, 60) { # Note: the parenthesis are superfluous here - # (sometimes called "superstitious parentheses") - .say if $_ > 50 ff *; # Once the flip-flop reaches a number greater than 50, - # it'll never go back to `False` - #=> 60 3 40 60 -} - -# You can also use this property to create an `If` -# that'll not go through the first time : -for <a b c> { - .say if * ^ff *; # the flip-flop is `True` and never goes back to `False`, - # but the `^` makes it *not run* on the first iteration - #=> b c -} - - ### Regular Expressions # I'm sure a lot of you have been waiting for this one. # Well, now that you know a good deal of Perl 6 already, we can get started. @@ -1470,6 +1375,105 @@ multi MAIN('import', File, Str :$as) { ... } # omitting parameter name # As you can see, this is *very* powerful. # It even went as far as to show inline the constants. # (the type is only displayed if the argument is `$`/is named) + +### +### APPENDIX A: +### +### List of things +### + +# It's considered by now you know the Perl6 basics. +# This section is just here to list some common operations, +# but which are not in the "main part" of the tutorial to bloat it up + +## Operators + + +## * Sort comparison +# They return one value of the `Order` enum : `Less`, `Same` and `More` +# (which numerify to -1, 0 or +1). +1 <=> 4; # sort comparison for numerics +'a' leg 'b'; # sort comparison for string +$obj eqv $obj2; # sort comparison using eqv semantics + +## * Generic ordering +3 before 4; # True +'b' after 'a'; # True + +## * Short-circuit default operator +# Like `or` and `||`, but instead returns the first *defined* value : +say Any // Nil // 0 // 5; #=> 0 + +## * Short-circuit exclusive or (XOR) +# Returns `True` if one (and only one) of its arguments is true +say True ^^ False; #=> True +## * Flip Flop +# The flip flop operators (`ff` and `fff`, equivalent to P5's `..`/`...`). +# are operators that take two predicates to test: +# They are `False` until their left side returns `True`, then are `True` until +# their right side returns `True`. +# Like for ranges, you can exclude the iteration when it became `True`/`False` +# by using `^` on either side. +# Let's start with an example : +for <well met young hero we shall meet later> { + # by default, `ff`/`fff` smart-match (`~~`) against `$_`: + if 'met' ^ff 'meet' { # Won't enter the if for "met" + # (explained in details below). + .say + } + + if rand == 0 ff rand == 1 { # compare variables other than `$_` + say "This ... probably will never run ..."; + } +} +# This will print "young hero we shall meet" (excluding "met"): +# the flip-flop will start returning `True` when it first encounters "met" +# (but will still return `False` for "met" itself, due to the leading `^` +# on `ff`), until it sees "meet", which is when it'll start returning `False`. + +# The difference between `ff` (awk-style) and `fff` (sed-style) is that +# `ff` will test its right side right when its left side changes to `True`, +# and can get back to `False` right away +# (*except* it'll be `True` for the iteration that matched) - +# While `fff` will wait for the next iteration to +# try its right side, once its left side changed: +.say if 'B' ff 'B' for <A B C B A>; #=> B B + # because the right-hand-side was tested + # directly (and returned `True`). + # "B"s are printed since it matched that time + # (it just went back to `False` right away). +.say if 'B' fff 'B' for <A B C B A>; #=> B C B + # The right-hand-side wasn't tested until + # `$_` became "C" + # (and thus did not match instantly). + +# A flip-flop can change state as many times as needed: +for <test start print it stop not printing start print again stop not anymore> { + .say if $_ eq 'start' ^ff^ $_ eq 'stop'; # exclude both "start" and "stop", + #=> "print this printing again" +} + +# you might also use a Whatever Star, +# which is equivalent to `True` for the left side or `False` for the right: +for (1, 3, 60, 3, 40, 60) { # Note: the parenthesis are superfluous here + # (sometimes called "superstitious parentheses") + .say if $_ > 50 ff *; # Once the flip-flop reaches a number greater than 50, + # it'll never go back to `False` + #=> 60 3 40 60 +} + +# You can also use this property to create an `If` +# that'll not go through the first time : +for <a b c> { + .say if * ^ff *; # the flip-flop is `True` and never goes back to `False`, + # but the `^` makes it *not run* on the first iteration + #=> b c +} + + +# - `===` is value identity and uses `.WHICH` on the objects to compare them +# - `=:=` is container identity and uses `VAR()` on the objects to compare them + ``` If you want to go further, you can: @@ -1477,5 +1481,5 @@ If you want to go further, you can: - Read the [Perl 6 Advent Calendar](http://perl6advent.wordpress.com/). This is probably the greatest source of Perl 6 information, snippets and such. - Come along on `#perl6` at `irc.freenode.net`. The folks here are always helpful. - Check the [source of Perl 6's functions and classes](https://github.com/rakudo/rakudo/tree/nom/src/core). Rakudo is mainly written in Perl 6 (with a lot of NQP, "Not Quite Perl", a Perl 6 subset easier to implement and optimize). - - Read the [Synopses](perlcabal.org/syn). They explain it from an implementor point-of-view, but it's still very interesting. + - Read [the language design documents](http://design.perl6.org). They explain P6 from an implementor point-of-view, but it's still very interesting. diff --git a/pogo.html.markdown b/pogo.html.markdown index 60a83edd..aa5d49f3 100644 --- a/pogo.html.markdown +++ b/pogo.html.markdown @@ -199,4 +199,4 @@ That's it. Download [Node.js](http://nodejs.org/) and `npm install pogo`. -There is plenty of documentation on [http://pogoscript.org/](http://pogoscript.org/), inlcuding a [cheat sheet](http://pogoscript.org/cheatsheet.html), a [guide](http://pogoscript.org/guide/), and how [Pogoscript translates to Javascript](http://featurist.github.io/pogo-examples/). Get in touch on the [google group](http://groups.google.com/group/pogoscript) if you have questions! +There is plenty of documentation on [http://pogoscript.org/](http://pogoscript.org/), including a [cheat sheet](http://pogoscript.org/cheatsheet.html), a [guide](http://pogoscript.org/guide/), and how [Pogoscript translates to Javascript](http://featurist.github.io/pogo-examples/). Get in touch on the [google group](http://groups.google.com/group/pogoscript) if you have questions! diff --git a/pt-br/clojure-pt.html.markdown b/pt-br/clojure-pt.html.markdown new file mode 100644 index 00000000..7e8b3f7b --- /dev/null +++ b/pt-br/clojure-pt.html.markdown @@ -0,0 +1,384 @@ +--- +language: clojure +filename: learnclojure-pt.clj +contributors: + - ["Adam Bard", "http://adambard.com/"] +translators: + - ["Mariane Siqueira Machado", "https://twitter.com/mariane_sm"] +lang: pt-br +--- + +Clojure é uma linguagem da família do Lisp desenvolvida para a JVM (máquina virtual Java). Possui uma ênfase muito mais forte em [programação funcional] (https://pt.wikipedia.org/wiki/Programa%C3%A7%C3%A3o_funcional) pura do que Common Lisp, mas inclui diversas utilidades [STM](https://en.wikipedia.org/wiki/Software_transactional_memory) para lidar com estado a medida que isso se torna necessário. + +Essa combinação permite gerenciar processamento concorrente de maneira muito simples, e frequentemente de maneira automática. + +(Sua versão de clojure precisa ser pelo menos 1.2) + + +```clojure +; Comentários começam por ponto e vírgula + +; Clojure é escrito em "forms", os quais são simplesmente +; listas de coisas dentro de parênteses, separados por espaços em branco. + +; O "reader" (leitor) de Clojure presume que o primeiro elemento de +; uma par de parênteses é uma função ou macro, e que os resto são argumentos. + +: A primeira chamada de um arquivo deve ser ns, para configurar o namespace (espaço de nomes) +(ns learnclojure) + +; Alguns exemplos básicos: + +; str cria uma string concatenando seus argumentos +(str "Hello" " " "World") ; => "Hello World" + +; Cálculos são feitos de forma direta e intuitiva +(+ 1 1) ; => 2 +(- 2 1) ; => 1 +(* 1 2) ; => 2 +(/ 2 1) ; => 2 + +; Você pode comparar igualdade utilizando = +(= 1 1) ; => true +(= 2 1) ; => false + +; Negação para operações lógicas +(not true) ; => false + +; Aninhar "forms" funciona como esperado +(+ 1 (- 3 2)) ; = 1 + (3 - 2) => 2 + +; Tipos +;;;;;;;;;;;;; + +; Clojure usa os tipos de objetos de Java para booleanos, strings e números. +; Use `class` para inspecioná-los +(class 1) ; Literais Integer são java.lang.Long por padrão +(class 1.); Literais Float são java.lang.Double +(class ""); Strings são sempre com aspas duplas, e são java.lang.String +(class false) ; Booleanos são java.lang.Boolean +(class nil); O valor "null" é chamado nil + +; Se você quiser criar um lista de literais, use aspa simples para +; ela não ser avaliada +'(+ 1 2) ; => (+ 1 2) +; (que é uma abreviação de (quote (+ 1 2))) + +; É possível avaliar uma lista com aspa simples +(eval '(+ 1 2)) ; => 3 + +; Coleções e sequências +;;;;;;;;;;;;;;;;;;; + +; Listas são estruturas encadeadas, enquanto vetores são implementados como arrays. +; Listas e Vetores são classes Java também! +(class [1 2 3]); => clojure.lang.PersistentVector +(class '(1 2 3)); => clojure.lang.PersistentList + +; Uma lista é escrita como (1 2 3), mas temos que colocar a aspa +; simples para impedir o leitor (reader) de pensar que é uma função. +; Também, (list 1 2 3) é o mesmo que '(1 2 3) + +; "Coleções" são apenas grupos de dados +; Listas e vetores são ambos coleções: +(coll? '(1 2 3)) ; => true +(coll? [1 2 3]) ; => true + +; "Sequências" (seqs) são descrições abstratas de listas de dados. +; Apenas listas são seqs. +(seq? '(1 2 3)) ; => true +(seq? [1 2 3]) ; => false + +; Um seq precisa apenas prover uma entrada quando é acessada. +; Portanto, já que seqs podem ser avaliadas sob demanda (lazy) -- elas podem definir séries infinitas: +(range 4) ; => (0 1 2 3) +(range) ; => (0 1 2 3 4 ...) (uma série infinita) +(take 4 (range)) ; (0 1 2 3) + +; Use cons para adicionar um item no início de uma lista ou vetor +(cons 4 [1 2 3]) ; => (4 1 2 3) +(cons 4 '(1 2 3)) ; => (4 1 2 3) + +; Conj adiciona um item em uma coleção sempre do jeito mais eficiente. +; Para listas, elas inserem no início. Para vetores, é inserido no final. +(conj [1 2 3] 4) ; => [1 2 3 4] +(conj '(1 2 3) 4) ; => (4 1 2 3) + +; Use concat para concatenar listas e vetores +(concat [1 2] '(3 4)) ; => (1 2 3 4) + +; Use filter, map para interagir com coleções +(map inc [1 2 3]) ; => (2 3 4) +(filter even? [1 2 3]) ; => (2) + +; Use reduce para reduzi-los +(reduce + [1 2 3 4]) +; = (+ (+ (+ 1 2) 3) 4) +; => 10 + +; Reduce pode receber um argumento para o valor inicial +(reduce conj [] '(3 2 1)) +; = (conj (conj (conj [] 3) 2) 1) +; => [3 2 1] + +; Funções +;;;;;;;;;;;;;;;;;;;;; + +; Use fn para criar novas funções. Uma função sempre retorna +; sua última expressão. +(fn [] "Hello World") ; => fn + +; (É necessário colocar parênteses para chamá-los) +((fn [] "Hello World")) ; => "Hello World" + +; Você pode atribuir valores a variáveis utilizando def +(def x 1) +x ; => 1 + +; Atribua uma função para uma var +(def hello-world (fn [] "Hello World")) +(hello-world) ; => "Hello World" + +; Você pode abreviar esse processo usando defn +(defn hello-world [] "Hello World") + +; O [] é uma lista de argumentos para um função. +(defn hello [name] + (str "Hello " name)) +(hello "Steve") ; => "Hello Steve" + +; Você pode ainda usar essa abreviação para criar funcões: +(def hello2 #(str "Hello " %1)) +(hello2 "Fanny") ; => "Hello Fanny" + +; Vocé pode ter funções multi-variadic, isto é, com um número variável de argumentos +(defn hello3 + ([] "Hello World") + ([name] (str "Hello " name))) +(hello3 "Jake") ; => "Hello Jake" +(hello3) ; => "Hello World" + +; Funções podem agrupar argumentos extras em uma seq +(defn count-args [& args] + (str "You passed " (count args) " args: " args)) +(count-args 1 2 3) ; => "You passed 3 args: (1 2 3)" + +; Você pode misturar argumentos regulares e argumentos em seq +(defn hello-count [name & args] + (str "Hello " name ", you passed " (count args) " extra args")) +(hello-count "Finn" 1 2 3) +; => "Hello Finn, you passed 3 extra args" + + +; Mapas +;;;;;;;;;; + +; Hash maps e array maps compartilham uma mesma interface. Hash maps são mais +; rápidos para pesquisa mas não mantém a ordem da chave. +(class {:a 1 :b 2 :c 3}) ; => clojure.lang.PersistentArrayMap +(class (hash-map :a 1 :b 2 :c 3)) ; => clojure.lang.PersistentHashMap + +; Arraymaps pode automaticamente se tornar hashmaps através da maioria das +; operações se eles ficarem grandes o suficiente, portanto não há necessida de +; se preocupar com isso. + +;Mapas podem usar qualquer valor que se pode derivar um hash como chave + + +; Mapas podem usar qualquer valor em que se pode derivar um hash como chave, +; mas normalmente palavras-chave (keywords) são melhores. +; Keywords são como strings mas com algumas vantagens. +(class :a) ; => clojure.lang.Keyword + +(def stringmap {"a" 1, "b" 2, "c" 3}) +stringmap ; => {"a" 1, "b" 2, "c" 3} + +(def keymap {:a 1, :b 2, :c 3}) +keymap ; => {:a 1, :c 3, :b 2} + +; A propósito, vírgulas são sempre tratadas como espaçoes em branco e não fazem nada. + +; Recupere o valor de um mapa chamando ele como uma função +(stringmap "a") ; => 1 +(keymap :a) ; => 1 + +; Uma palavra-chave pode ser usada pra recuperar os valores de um mapa +(:b keymap) ; => 2 + +; Não tente isso com strings +;("a" stringmap) +; => Exception: java.lang.String cannot be cast to clojure.lang.IFn + +; Buscar uma chave não presente retorna nil +(stringmap "d") ; => nil + +; Use assoc para adicionar novas chaves para hash-maps +(def newkeymap (assoc keymap :d 4)) +newkeymap ; => {:a 1, :b 2, :c 3, :d 4} + +; Mas lembre-se, tipos em Clojure são sempre imutáveis! +keymap ; => {:a 1, :b 2, :c 3} + +; Use dissoc para remover chaves +(dissoc keymap :a :b) ; => {:c 3} + +; Conjuntos +;;;;;; + +(class #{1 2 3}) ; => clojure.lang.PersistentHashSet +(set [1 2 3 1 2 3 3 2 1 3 2 1]) ; => #{1 2 3} + +; Adicione um membro com conj +(conj #{1 2 3} 4) ; => #{1 2 3 4} + +; Remova um membro com disj +(disj #{1 2 3} 1) ; => #{2 3} + +; Test por existência usando set como função: +(#{1 2 3} 1) ; => 1 +(#{1 2 3} 4) ; => nil + +; Existem muitas outras funções no namespace clojure.sets + +; Forms úteis +;;;;;;;;;;;;;;;;; + +; Construções lógicas em Clojure são como macros, e +; se parecem com as demais +(if false "a" "b") ; => "b" +(if false "a") ; => nil + +; Use let para criar um novo escopo associando sîmbolos a valores (bindings) +(let [a 1 b 2] + (> a b)) ; => false + +; Agrupe comandos juntos com "do" +(do + (print "Hello") + "World") ; => "World" (prints "Hello") + +; Funções tem um do implícito +(defn print-and-say-hello [name] + (print "Saying hello to " name) + (str "Hello " name)) +(print-and-say-hello "Jeff") ;=> "Hello Jeff" (prints "Saying hello to Jeff") + +; Assim como let +(let [name "Urkel"] + (print "Saying hello to " name) + (str "Hello " name)) ; => "Hello Urkel" (prints "Saying hello to Urkel") + +; Módulos +;;;;;;;;;;;;;;; + +; Use "use" para poder usar todas as funções de um modulo +(use 'clojure.set) + +; Agora nós podemos usar operações com conjuntos +(intersection #{1 2 3} #{2 3 4}) ; => #{2 3} +(difference #{1 2 3} #{2 3 4}) ; => #{1} + +; Você pode escolher um subconjunto de funções para importar +(use '[clojure.set :only [intersection]]) + +; Use require para importar um módulo +(require 'clojure.string) + +; Use / para chamar funções de um módulo +; Aqui, o módulo é clojure.string e a função é blank? +(clojure.string/blank? "") ; => true + +; Você pode dar para um módulo um nome mais curto no import +(require '[clojure.string :as str]) +(str/replace "This is a test." #"[a-o]" str/upper-case) ; => "THIs Is A tEst." +; (#"" denota uma expressão regular literal) + +; Você pode usar require (e até "use", mas escolha require) de um namespace utilizando :require. +; Não é necessário usar aspa simples nos seus módulos se você usar desse jeito. +(ns test + (:require + [clojure.string :as str] + [clojure.set :as set])) + +; Java +;;;;;;;;;;;;;;;;; + +; Java tem uma biblioteca padrão enorme e muito útil, +; portanto é importante aprender como utiliza-la. + +; Use import para carregar um modulo java +(import java.util.Date) + +; Você pode importar usando ns também. +(ns test + (:import java.util.Date + java.util.Calendar)) + +; Use o nome da clase com um "." no final para criar uma nova instância +(Date.) ; <a date object> + +; Use . para chamar métodos. Ou, use o atalho ".method" +(. (Date.) getTime) ; <a timestamp> +(.getTime (Date.)) ; exatamente a mesma coisa. + +; Use / para chamar métodos estáticos +(System/currentTimeMillis) ; <a timestamp> (o módulo System está sempre presente) + +; Use doto para pode lidar com classe (mutáveis) de forma mais tolerável +(import java.util.Calendar) +(doto (Calendar/getInstance) + (.set 2000 1 1 0 0 0) + .getTime) ; => A Date. set to 2000-01-01 00:00:00 + +; STM +;;;;;;;;;;;;;;;;; + +; Software Transactional Memory é o mecanismo que Clojure usa para gerenciar +; estado persistente. Tem algumas construções em Clojure que o utilizam. + +; O atom é o mais simples. Passe pra ele um valor inicial +(def my-atom (atom {})) + +; Atualize o atom com um swap!. +; swap! pega uma funçnao and chama ela com o valor atual do atom +; como primeiro argumento, e qualquer argumento restante como o segundo +(swap! my-atom assoc :a 1) ; Coloca o valor do átomo my-atom como o resultado de (assoc {} :a 1) +(swap! my-atom assoc :b 2) ; Coloca o valor do átomo my-atom como o resultado de (assoc {:a 1} :b 2) + +; Use '@' para desreferenciar um atom e acessar seu valor +my-atom ;=> Atom<#...> (Retorna o objeto do Atom) +@my-atom ; => {:a 1 :b 2} + +; Abaixo um contador simples usando um atom +(def counter (atom 0)) +(defn inc-counter [] + (swap! counter inc)) + +(inc-counter) +(inc-counter) +(inc-counter) +(inc-counter) +(inc-counter) + +@counter ; => 5 + +; Outras construção STM são refs e agents. +; Refs: http://clojure.org/refs +; Agents: http://clojure.org/agents +``` + +### Leitura adicional + +Esse tutorial está longe de ser exaustivo, mas deve ser suficiente para que você possa começar. + +Clojure.org tem vários artigos: +[http://clojure.org/](http://clojure.org/) + +Clojuredocs.org tem documentação com exemplos para quase todas as funções principais (pertecentes ao core): +[http://clojuredocs.org/quickref/Clojure%20Core](http://clojuredocs.org/quickref/Clojure%20Core) + +4Clojure é um grande jeito de aperfeiçoar suas habilidades em Clojure/Programação Funcional: +[http://www.4clojure.com/](http://www.4clojure.com/) + +Clojure-doc.org tem um bom número de artigos para iniciantes: +[http://clojure-doc.org/](http://clojure-doc.org/) diff --git a/pt-br/hy-pt.html.markdown b/pt-br/hy-pt.html.markdown new file mode 100644 index 00000000..4230579d --- /dev/null +++ b/pt-br/hy-pt.html.markdown @@ -0,0 +1,176 @@ +--- +language: hy +filename: learnhy.hy +contributors: + - ["Abhishek L", "http://twitter.com/abhishekl"] +translators: + - ["Miguel Araújo", "https://github.com/miguelarauj1o"] +lang: pt-br +--- + +Hy é um dialeto de Lisp escrito sobre Python. Isto é possível convertendo +código Hy em árvore sintática abstrata python (ast). Portanto, isto permite +hy chamar código python nativo e vice-versa. + +Este tutorial funciona para hy ≥ 0.9.12 + +```clojure +;; Isso dá uma introdução básica em hy, como uma preliminar para o link abaixo +;; http://try-hy.appspot.com +;; +; Comentários em ponto-e-vírgula, como em outros LISPS + +;; s-noções básicas de expressão +; programas Lisp são feitos de expressões simbólicas ou sexps que se assemelham +(some-function args) +; agora o essencial "Olá mundo" +(print "hello world") + +;; Tipos de dados simples +; Todos os tipos de dados simples são exatamente semelhantes aos seus homólogos +; em python que +42 ; => 42 +3.14 ; => 3.14 +True ; => True +4+10j ; => (4+10j) um número complexo + +; Vamos começar com um pouco de aritmética muito simples +(+ 4 1) ;=> 5 +; o operador é aplicado a todos os argumentos, como outros lisps +(+ 4 1 2 3) ;=> 10 +(- 2 1) ;=> 1 +(* 4 2) ;=> 8 +(/ 4 1) ;=> 4 +(% 4 2) ;=> 0 o operador módulo +; exponenciação é representado pelo operador ** como python +(** 3 2) ;=> 9 +; formas aninhadas vão fazer a coisa esperada +(+ 2 (* 4 2)) ;=> 10 +; também operadores lógicos e ou não e igual etc. faz como esperado +(= 5 4) ;=> False +(not (= 5 4)) ;=> True + +;; variáveis +; variáveis são definidas usando SETV, nomes de variáveis podem usar utf-8, exceto +; for ()[]{}",'`;#| +(setv a 42) +(setv π 3.14159) +(def *foo* 42) +;; outros tipos de dados de armazenamento +; strings, lists, tuples & dicts +; estes são exatamente os mesmos tipos de armazenamento de python +"hello world" ;=> "hello world" +; operações de string funcionam semelhante em python +(+ "hello " "world") ;=> "hello world" +; Listas são criadas usando [], a indexação começa em 0 +(setv mylist [1 2 3 4]) +; tuplas são estruturas de dados imutáveis +(setv mytuple (, 1 2)) +; dicionários são pares de valores-chave +(setv dict1 {"key1" 42 "key2" 21}) +; :nome pode ser utilizado para definir palavras-chave em hy que podem ser utilizados para as chaves +(setv dict2 {:key1 41 :key2 20}) +; usar 'get' para obter o elemento em um índice/key +(get mylist 1) ;=> 2 +(get dict1 "key1") ;=> 42 +; Alternativamente, se foram utilizadas palavras-chave que podem ser chamadas diretamente +(:key1 dict2) ;=> 41 + +;; funções e outras estruturas de programa +; funções são definidas usando defn, o último sexp é devolvido por padrão +(defn greet [name] + "A simple greeting" ; uma docstring opcional + (print "hello " name)) + +(greet "bilbo") ;=> "hello bilbo" + +; funções podem ter argumentos opcionais, bem como argumentos-chave +(defn foolists [arg1 &optional [arg2 2]] + [arg1 arg2]) + +(foolists 3) ;=> [3 2] +(foolists 10 3) ;=> [10 3] + +; funções anônimas são criados usando construtores 'fn' ou 'lambda' +; que são semelhantes para 'defn' +(map (fn [x] (* x x)) [1 2 3 4]) ;=> [1 4 9 16] + +;; operações de sequência +; hy tem algumas utils embutidas para operações de sequência, etc. +; recuperar o primeiro elemento usando 'first' ou 'car' +(setv mylist [1 2 3 4]) +(setv mydict {"a" 1 "b" 2}) +(first mylist) ;=> 1 + +; corte listas usando 'slice' +(slice mylist 1 3) ;=> [2 3] + +; obter elementos de uma lista ou dict usando 'get' +(get mylist 1) ;=> 2 +(get mydict "b") ;=> 2 +; lista de indexação começa a partir de 0, igual em python +; assoc pode definir elementos em chaves/índices +(assoc mylist 2 10) ; faz mylist [1 2 10 4] +(assoc mydict "c" 3) ; faz mydict {"a" 1 "b" 2 "c" 3} +; há toda uma série de outras funções essenciais que torna o trabalho com +; sequências uma diversão + +;; Python interop +;; importação funciona exatamente como em python +(import datetime) +(import [functools [partial reduce]]) ; importa fun1 e fun2 do module1 +(import [matplotlib.pyplot :as plt]) ; fazendo uma importação em foo como em bar +; todos os métodos de python embutidas etc. são acessíveis a partir hy +; a.foo(arg) is called as (.foo a arg) +(.split (.strip "hello world ")) ;=> ["hello" "world"] + +;; Condicionais +; (if condition (body-if-true) (body-if-false) +(if (= passcode "moria") + (print "welcome") + (print "Speak friend, and Enter!")) + +; aninhe múltiplas cláusulas 'if else if' com cond +(cond + [(= someval 42) + (print "Life, universe and everything else!")] + [(> someval 42) + (print "val too large")] + [(< someval 42) + (print "val too small")]) + +; declarações de grupo com 'do', essas são executadas sequencialmente +; formas como defn tem um 'do' implícito +(do + (setv someval 10) + (print "someval is set to " someval)) ;=> 10 + +; criar ligações lexicais com 'let', todas as variáveis definidas desta forma +; tem escopo local +(let [[nemesis {"superman" "lex luther" + "sherlock" "moriarty" + "seinfeld" "newman"}]] + (for [(, h v) (.items nemesis)] + (print (.format "{0}'s nemesis was {1}" h v)))) + +;; classes +; classes são definidas da seguinte maneira +(defclass Wizard [object] + [[--init-- (fn [self spell] + (setv self.spell spell) ; init a mágica attr + None)] + [get-spell (fn [self] + self.spell)]]) + +;; acesse hylang.org +``` + +### Outras Leituras + +Este tutorial é apenas uma introdução básica para hy/lisp/python. + +Docs Hy: [http://hy.readthedocs.org](http://hy.readthedocs.org) + +Repo Hy no Github: [http://github.com/hylang/hy](http://github.com/hylang/hy) + +Acesso ao freenode irc com #hy, hashtag no twitter: #hylang diff --git a/pt-br/ruby-pt.html.markdown b/pt-br/ruby-pt.html.markdown index 4a8a1b5c..89a051d4 100644 --- a/pt-br/ruby-pt.html.markdown +++ b/pt-br/ruby-pt.html.markdown @@ -33,7 +33,7 @@ Você não deve usar também 10 * 2 #=> 20 35 / 5 #=> 7 -# Aritimética é apenas açúcar sintático +# Aritmética é apenas açúcar sintático # para chamar um método de um objeto 1.+(3) #=> 4 10.* 5 #=> 50 @@ -129,7 +129,7 @@ array = [1, "Oi", false] #=> => [1, "Oi", false] array[0] #=> 1 array[12] #=> nil -# Como aritimética, o acesso via [var] +# Como aritmética, o acesso via [var] # é apenas açúcar sintático # para chamar o método [] de um objeto array.[] 0 #=> 1 @@ -171,7 +171,7 @@ end # Desde o Ruby 1.9, temos uma sintaxe especial quando usamos símbolos como chaves (keys) -novo_hash = { defcon: 3, acao: true} +novo_hash = {defcon: 3, acao: true} novo_hash.keys #=> [:defcon, :acao] @@ -183,9 +183,9 @@ novo_hash.keys #=> [:defcon, :acao] if true "Se verdadeiro" elsif false - "else if, opicional" + "else if, opcional" else - "else, também é opicional" + "else, também é opcional" end for contador in 1..5 @@ -259,7 +259,7 @@ end # Argumentos de métodos são separados por uma vírgula somar 3, 4 #=> 7 -somar somar(3,4), 5 #=> 12 +somar(3,4), 5 #=> 12 # yield # Todos os métodos possuem implicitamente um paramêntro opcional que é um bloco diff --git a/pt-br/swift-pt.html.markdown b/pt-br/swift-pt.html.markdown new file mode 100644 index 00000000..a29490b0 --- /dev/null +++ b/pt-br/swift-pt.html.markdown @@ -0,0 +1,500 @@ +--- +language: swift +contributors: + - ["Grant Timmerman", "http://github.com/grant"], + - ["Christopher Bess", "http://github.com/cbess"] +translators: + - ["Mariane Siqueira Machado", "https://twitter.com/mariane_sm"] +lang: pt-br +filename: learnswift.swift +--- + +Swift é uma linguagem de programação para desenvolvimento de aplicações no iOS e OS X criada pela Apple. Criada para +coexistir com Objective-C e para ser mais resiliente a código com erros, Swift foi apresentada em 2014 na Apple's +developer conference WWDC. Foi construída com o compilador LLVM já incluído no Xcode 6 beta. + +O livro oficial [Swift Programming Language] (https://itunes.apple.com/us/book/swift-programming-language/id881256329) da +Apple já está disponível via IBooks (apenas em inglês). + +Confira também o tutorial completo de Swift da Apple [getting started guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/LandingPage/index.html), também disponível apenas em inglês. + +```swift +// importa um módulo +import UIKit + +// +// MARK: Noções básicas +// + +// Xcode supporta anotações para seu código e lista elas na barra de atalhos +// MARK: Marca uma sessão +// TODO: Faça algo logo +// FIXME: Conserte esse código + +println("Hello, world") + +// Valores em variáveis (var) podem ter seu valor alterado depois de declarados. +// Valores em constantes (let) NÃO podem ser alterados depois de declarados. + +var myVariable = 42 +let øπΩ = "value" // nomes de variáveis em unicode +let π = 3.1415926 +let convenience = "keyword" // nome de variável contextual +let weak = "keyword"; let override = "another keyword" // comandos podem ser separados por uma ponto e vírgula +let `class` = "keyword" // Crases permitem que palavras-chave seja usadas como nome de variáveis +let explicitDouble: Double = 70 +let intValue = 0007 // 7 +let largeIntValue = 77_000 // 77000 +let label = "some text " + String(myVariable) // Coerção +let piText = "Pi = \(π), Pi 2 = \(π * 2)" // Interpolação de strings + +// Constrói valores específicos +// Utiliza configuração de build -D +#if false + println("Not printed") + let buildValue = 3 +#else + let buildValue = 7 +#endif +println("Build value: \(buildValue)") // Build value: 7 + +/* + Optionals fazem parte da linguagem e permitem que você armazene um + valor `Some` (algo) ou `None` (nada). + + Como Swift requer que todas as propriedades tenham valores, até mesmo nil deve + ser explicitamente armazenado como um valor Optional. + + Optional<T> é uma enum. +*/ +var someOptionalString: String? = "optional" // Pode ser nil +// o mesmo acima, mas ? é um operador pós-fixado (açúcar sintático) +var someOptionalString2: Optional<String> = "optional" + +if someOptionalString != nil { + // Eu não sou nil + if someOptionalString!.hasPrefix("opt") { + println("has the prefix") + } + + let empty = someOptionalString?.isEmpty +} +someOptionalString = nil + +// Optional implicitamente desempacotado (unwrapped) +var unwrappedString: String! = "Valor é esperado." +// o mesmo acima, mas ? é um operador pósfixado (açúcar sintático) +var unwrappedString2: ImplicitlyUnwrappedOptional<String> = "Valor é esperado." + +if let someOptionalStringConstant = someOptionalString { + // Tem `Some` (algum) valor, não nil + if !someOptionalStringConstant.hasPrefix("ok") { + // não possui o prefixo + } +} + +// Swift tem suporte para armazenar um valor de qualquer tipo. +// AnyObject == id +// Ao contrário de Objective-C `id`, AnyObject funciona com qualquer valor (Class, Int, struct, etc) +var anyObjectVar: AnyObject = 7 +anyObjectVar = "Mudou o valor para string, não é uma boa prática, mas é possível." + +/* +Comentário aqui + /* + Comentários aninhados também são suportados + */ +*/ + +// +// MARK: Coleções +// + +/* + Tipos Array e Dicionário são structs. Portanto `let` e `var` + também indicam se são mutáveis (var) ou imutáveis (let) quando declarados + com esses tipos. +*/ + +// Array +var shoppingList = ["catfish", "water", "lemons"] +shoppingList[1] = "bottle of water" +let emptyArray = [String]() // imutável +var emptyMutableArray = [String]() // mutável + + +// Dicionário +var occupations = [ + "Malcolm": "Captain", + "kaylee": "Mechanic" +] +occupations["Jayne"] = "Public Relations" +let emptyDictionary = [String: Float]() // imutável +var emptyMutableDictionary = [String: Float]() // mutável + + +// +// MARK: Controle de fluxo +// + +// laço for (array) +let myArray = [1, 1, 2, 3, 5] +for value in myArray { + if value == 1 { + println("One!") + } else { + println("Not one!") + } +} + +// laço for (dicionário) +var dict = ["one": 1, "two": 2] +for (key, value) in dict { + println("\(key): \(value)") +} + +// laço for (alcance) +for i in -1...shoppingList.count { + println(i) +} +shoppingList[1...2] = ["steak", "peacons"] +// use ..< para excluir o último número + +// laço while (enquanto) +var i = 1 +while i < 1000 { + i *= 2 +} + +// laço do-while +do { + println("hello") +} while 1 == 2 + +// Switch +let vegetable = "red pepper" +switch vegetable { +case "celery": + let vegetableComment = "Add some raisins and make ants on a log." +case "cucumber", "watercress": + let vegetableComment = "That would make a good tea sandwich." +case let x where x.hasSuffix("pepper"): + let vegetableComment = "Is it a spicy \(x)?" +default: // required (in order to cover all possible input) + let vegetableComment = "Everything tastes good in soup." +} + + +// +// MARK: Funções +// + +// Funções são tipos de primeira classe, o que significa que eles podem ser aninhados +// em funções e podem ser passados como parâmetros + +// Funções Swift com cabeçalhos doc (formato como reStructedText) +/** +Uma operação de saudação + +- Um bullet em documentos +- Outro bullet + +:param: nome A nome +:param: dia A dia +:returns: Uma string contendo o nome e o dia. +*/ +func greet(name: String, day: String) -> String { + return "Hello \(name), today is \(day)." +} +greet("Bob", "Tuesday") + +// Função que retorna múltiplos items em uma tupla +func getGasPrices() -> (Double, Double, Double) { + return (3.59, 3.69, 3.79) +} +let pricesTuple = getGasPrices() +let price = pricesTuple.2 // 3.79 +// Ignore valores de Tuplas (ou outros valores) usando _ (underscore) +let (_, price1, _) = pricesTuple // price1 == 3.69 +println(price1 == pricesTuple.1) // true +println("Gas price: \(price)") + +// Número variável de argumentos +func setup(numbers: Int...) { + // its an array + let number = numbers[0] + let argCount = numbers.count +} + +// Passando e retornando funções +func makeIncrementer() -> (Int -> Int) { + func addOne(number: Int) -> Int { + return 1 + number + } + return addOne +} +var increment = makeIncrementer() +increment(7) + +// passagem por referência +func swapTwoInts(inout a: Int, inout b: Int) { + let tempA = a + a = b + b = tempA +} +var someIntA = 7 +var someIntB = 3 +swapTwoInts(&someIntA, &someIntB) +println(someIntB) // 7 + + +// +// MARK: Closures +// +var numbers = [1, 2, 6] + +// Funções são casos especiais de closures ({}) + +// Exemplo de closure. +// `->` separa argumentos e tipo de retorno +// `in` separa o cabeçalho do closure do seu corpo +numbers.map({ + (number: Int) -> Int in + let result = 3 * number + return result +}) + +// Quando o tipo é conhecido, como abaixo, nós podemos fazer o seguinte +numbers = numbers.map({ number in 3 * number }) +// Ou até mesmo isso +//numbers = numbers.map({ $0 * 3 }) + +print(numbers) // [3, 6, 18] + +// Closure restante +numbers = sorted(numbers) { $0 > $1 } + +print(numbers) // [18, 6, 3] + +// Super atalho, já que o operador < infere os tipos + +numbers = sorted(numbers, < ) + +print(numbers) // [3, 6, 18] + +// +// MARK: Estruturas +// + +// Estruturas e classes tem funcionalidades muito similares +struct NamesTable { + let names: [String] + + // Custom subscript + subscript(index: Int) -> String { + return names[index] + } +} + +// Estruturas possuem um inicializador auto-gerado automático (implícito) +let namesTable = NamesTable(names: ["Me", "Them"]) +//let name = namesTable[2] +//println("Name is \(name)") // Name is Them + +// +// MARK: Classes +// + +// Classes, Estruturas e seus membros possuem três níveis de modificadores de acesso +// Eles são: internal (default), public, private + +public class Shape { + public func getArea() -> Int { + return 0; + } +} + +// Todos os métodos e propriedades de uma classe são públicos. +// Se você só precisa armazenar dados em um objeto estruturado, use `struct` + +internal class Rect: Shape { + var sideLength: Int = 1 + + // Getter e setter personalizado + private var perimeter: Int { + get { + return 4 * sideLength + } + set { + // `newValue` é uma variável implicita disponível para os setters + sideLength = newValue / 4 + } + } + + // Carregue uma propriedade sob demanda (lazy) + // subShape permanece nil (não inicializado) até seu getter ser chamado + lazy var subShape = Rect(sideLength: 4) + + // Se você não precisa de um getter e setter personalizado, + // mas ainda quer roda código antes e depois de configurar + // uma propriedade, você pode usar `willSet` e `didSet` + var identifier: String = "defaultID" { + // o argumento `willSet` será o nome da variável para o novo valor + willSet(someIdentifier) { + print(someIdentifier) + } + } + + init(sideLength: Int) { + self.sideLength = sideLength + // sempre chame super.init por último quand inicializar propriedades personalizadas (custom) + super.init() + } + + func shrink() { + if sideLength > 0 { + --sideLength + } + } + + override func getArea() -> Int { + return sideLength * sideLength + } +} + +// Uma classe básica `Square` que estende `Rect` +class Square: Rect { + convenience init() { + self.init(sideLength: 5) + } +} + +var mySquare = Square() +print(mySquare.getArea()) // 25 +mySquare.shrink() +print(mySquare.sideLength) // 4 + +// Compara instâncias, não é o mesmo que == o qual compara objetos +if mySquare === mySquare { + println("Yep, it's mySquare") +} + + +// +// MARK: Enums +// + +// Enums podem opcionalmente ser de um tipo específico ou não. +// Podem conter métodos do mesmo jeito que classes. + +enum Suit { + case Spades, Hearts, Diamonds, Clubs + func getIcon() -> String { + switch self { + case .Spades: return "♤" + case .Hearts: return "♡" + case .Diamonds: return "♢" + case .Clubs: return "♧" + } + } +} + + +// +// MARK: Protocolos +// + +// `protocol` pode requerer que os tipos que se adequam tenham +// propriedades de instância, métodos, operadores e subscripts. +protocol ShapeGenerator { + var enabled: Bool { get set } + func buildShape() -> Shape +} + +// Protocolos declarados com @objc permitem funções opcionais, +// que permitem verificar a confomidade +@objc protocol TransformShape { + optional func reshaped() + optional func canReshape() -> Bool +} + +class MyShape: Rect { + var delegate: TransformShape? + + func grow() { + sideLength += 2 + + if let allow = self.delegate?.canReshape?() { + // test for delegate then for method + // testa por delegação e então por método + self.delegate?.reshaped?() + } + } +} + + +// +// MARK: Outros +// + +// `extension`s: Adicionam uma funcionalidade extra para um tipo já existente. + +// Square agora "segue" o protocolo `Printable` +extension Square: Printable { + var description: String { + return "Area: \(self.getArea()) - ID: \(self.identifier)" + } +} + +println("Square: \(mySquare)") + +// Você pode também estender tipos embutidos (built-in) +extension Int { + var customProperty: String { + return "This is \(self)" + } + + func multiplyBy(num: Int) -> Int { + return num * self + } +} + +println(7.customProperty) // "This is 7" +println(14.multiplyBy(2)) // 42 + +// Generics: Similar com Java e C#. Use a palavra-chave `where` para +// especificar os requisitos do generics. + +func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? { + for (index, value) in enumerate(array) { + if value == valueToFind { + return index + } + } + return nil +} +let foundAtIndex = findIndex([1, 2, 3, 4], 3) +println(foundAtIndex == 2) // true + +// Operadores: +// Operadores personalizados (custom) podem começar com os seguintes caracteres: +// / = - + * % < > ! & | ^ . ~ +// ou +// Unicode math, símbolo, seta, e caracteres tipográficos ou de desenho. +prefix operator !!! {} + +// Um operador de prefixo que triplica o comprimento do lado do quadrado +// quando usado +prefix func !!! (inout shape: Square) -> Square { + shape.sideLength *= 3 + return shape +} + +// valor atual +println(mySquare.sideLength) // 4 + +// Troca o comprimento do lado usando um operador personalizado !!!, aumenta o lado por 3 +!!!mySquare +println(mySquare.sideLength) // 12 + +``` diff --git a/pt-br/xml-pt.html.markdown b/pt-br/xml-pt.html.markdown new file mode 100644 index 00000000..40ddbc3a --- /dev/null +++ b/pt-br/xml-pt.html.markdown @@ -0,0 +1,133 @@ +--- +language: xml +filename: learnxml.xml +contributors: + - ["João Farias", "https://github.com/JoaoGFarias"] +translators: + - ["Miguel Araújo", "https://github.com/miguelarauj1o"] +lang: pt-br +--- + +XML é uma linguagem de marcação projetada para armazenar e transportar dados. + +Ao contrário de HTML, XML não especifica como exibir ou formatar os dados, +basta carregá-lo. + +* Sintaxe XML + +```xml +<!-- Comentários em XML são feitos desta forma --> + +<?xml version="1.0" encoding="UTF-8"?> +<livraria> + <livro category="COZINHA"> + <titulo lang="en">Everyday Italian</titulo> + <autor>Giada De Laurentiis</autor> + <year>2005</year> + <preco>30.00</preco> + </livro> + <livro category="CRIANÇAS"> + <titulo lang="en">Harry Potter</titulo> + <autor>J K. Rowling</autor> + <year>2005</year> + <preco>29.99</preco> + </livro> + <livro category="WEB"> + <titulo lang="en">Learning XML</titulo> + <autor>Erik T. Ray</autor> + <year>2003</year> + <preco>39.95</preco> + </livro> +</livraria> + +<!-- Um típico arquivo XML é mostrado acima. + Ele começa com uma declaração, informando alguns metadados (opcional). + + XML usa uma estrutura de árvore. Acima, o nó raiz é "Livraria", que tem + três nós filhos, todos os 'Livros'. Esses nós tem mais nós filhos, + e assim por diante... + + Nós são criados usando tags abre/fecha, filhos são justamente os nós que + estão entre estes nós. --> + + +<!-- XML traz dois tipos de dados: + 1 - Atributos -> Isso é metadados sobre um nó. + Normalmente, o parser XML usa esta informação para armazenar os dados + corretamente. Caracteriza-se por aparecer em parênteses dentro da tag + de abertura. + 2 - Elementos -> É dados puros. + Isso é o que o analisador irá recuperar a partir do arquivo XML. + Elementos aparecem entre as tags de abertura e fechamento, + sem parênteses. --> + + +<!-- Abaixo, um elemento com dois atributos --> +<arquivo type="gif" id="4293">computer.gif</arquivo> + + +``` + +* Documento bem formatado x Validação + +Um documento XML é bem formatado se estiver sintaticamente correto.No entanto, +é possível injetar mais restrições no documento, utilizando definições de +documentos, tais como DTD e XML Schema. + +Um documento XML que segue uma definição de documento é chamado válido, sobre +esse documento. + +Com esta ferramenta, você pode verificar os dados XML fora da lógica da aplicação. + +```xml + +<!-- Abaixo, você pode ver uma versão simplificada do documento livraria, +com a adição de definição DTD.--> + +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE note SYSTEM "livraria.dtd"> +<livraria> + <livro category="COOKING"> + <titulo >Everyday Italian</titulo> + <preco>30.00</preco> + </livro> +</livraria> + +<!-- Este DTD poderia ser algo como:--> + +<!DOCTYPE note +[ +<!ELEMENT livraria (livro+)> +<!ELEMENT livro (titulo,preco)> +<!ATTLIST livro category CDATA "Literature"> +<!ELEMENT titulo (#PCDATA)> +<!ELEMENT preco (#PCDATA)> +]> + + +<!-- O DTD começa com uma declaração. + Na sequência, o nó raiz é declarado, o que requer uma ou mais crianças nós + 'Livro'. Cada 'Livro' deve conter exatamente um 'titulo' e um 'preco' e um + atributo chamado "categoria", com "Literatura", como o valor padrão. + Os nós "título" e "preço" contêm um conjunto de dados de caráter analisados.--> + +<!-- O DTD poderia ser declarado dentro do próprio arquivo XML .--> + +<?xml version="1.0" encoding="UTF-8"?> + +<!DOCTYPE note +[ +<!ELEMENT livraria (livro+)> +<!ELEMENT livro (titulo,preco)> +<!ATTLIST livro category CDATA "Literature"> +<!ELEMENT titulo (#PCDATA)> +<!ELEMENT preco (#PCDATA)> +]> + +<livraria> + <livro category="COOKING"> + <titulo >Everyday Italian</titulo> + <preco>30.00</preco> + </livro> +</livraria> +```
\ No newline at end of file diff --git a/python.html.markdown b/python.html.markdown index f7b0082c..da04d381 100644 --- a/python.html.markdown +++ b/python.html.markdown @@ -102,6 +102,9 @@ not False # => True # Strings can be added too! "Hello " + "world!" # => "Hello world!" +# ... or multiplied +"Hello" * 3 # => "HelloHelloHello" + # A string can be treated like a list of characters "This is a string"[0] # => 'T' @@ -136,11 +139,12 @@ bool("") # => False ## 2. Variables and Collections #################################################### -# Python has a print function, available in versions 2.7 and 3... -print("I'm Python. Nice to meet you!") -# and an older print statement, in all 2.x versions but removed from 3. -print "I'm also Python!" - +# Python has a print statement, in all 2.x versions but removed from 3. +print "I'm Python. Nice to meet you!" +# Python also has a print function, available in versions 2.7 and 3... +# but for 2.7 you need to add the import (uncommented): +# from __future__ import print_function +print("I'm also Python! ") # No need to declare variables before assigning to them. some_var = 5 # Convention is to use lower_case_with_underscores @@ -170,6 +174,10 @@ li.append(3) # li is now [1, 2, 4, 3] again. # Access a list like you would any array li[0] # => 1 +# Assign new values to indexes that have already been initialized with = +li[0] = 42 +li[0] # => 42 +li[0] = 1 # Note: setting it back to the original value # Look at the last element li[-1] # => 3 @@ -194,7 +202,8 @@ li[::-1] # => [3, 4, 2, 1] del li[2] # li is now [1, 2, 3] # You can add lists -li + other_li # => [1, 2, 3, 4, 5, 6] - Note: values for li and for other_li are not modified. +li + other_li # => [1, 2, 3, 4, 5, 6] +# Note: values for li and for other_li are not modified. # Concatenate lists with "extend()" li.extend(other_li) # Now li is [1, 2, 3, 4, 5, 6] @@ -255,17 +264,25 @@ filled_dict.get("four") # => None # The get method supports a default argument when the value is missing filled_dict.get("one", 4) # => 1 filled_dict.get("four", 4) # => 4 +# note that filled_dict.get("four") is still => None +# (get doesn't set the value in the dictionary) + +# set the value of a key with a syntax similar to lists +filled_dict["four"] = 4 # now, filled_dict["four"] => 4 # "setdefault()" inserts into a dictionary only if the given key isn't present filled_dict.setdefault("five", 5) # filled_dict["five"] is set to 5 filled_dict.setdefault("five", 6) # filled_dict["five"] is still 5 -# Sets store ... well sets +# Sets store ... well sets (which are like lists but can contain no duplicates) empty_set = set() # Initialize a "set()" with a bunch of values some_set = set([1, 2, 2, 3, 4]) # some_set is now set([1, 2, 3, 4]) +# order is not guaranteed, even though it may sometimes look sorted +another_set = set([4, 3, 2, 2, 1]) # another_set is now set([1, 2, 3, 4]) + # Since Python 2.7, {} can be used to declare a set filled_set = {1, 2, 2, 3, 4} # => {1, 2, 3, 4} @@ -371,7 +388,7 @@ add(y=6, x=5) # Keyword arguments can arrive in any order. # You can define functions that take a variable number of -# positional arguments +# positional args, which will be interpreted as a tuple if you do not use the * def varargs(*args): return args @@ -379,7 +396,7 @@ varargs(1, 2, 3) # => (1, 2, 3) # You can define functions that take a variable number of -# keyword arguments, as well +# keyword args, as well, which will be interpreted as a map if you do not use ** def keyword_args(**kwargs): return kwargs @@ -398,26 +415,33 @@ all_the_args(1, 2, a=3, b=4) prints: """ # When calling functions, you can do the opposite of args/kwargs! -# Use * to expand tuples and use ** to expand kwargs. +# Use * to expand positional args and use ** to expand keyword args. args = (1, 2, 3, 4) kwargs = {"a": 3, "b": 4} all_the_args(*args) # equivalent to foo(1, 2, 3, 4) all_the_args(**kwargs) # equivalent to foo(a=3, b=4) all_the_args(*args, **kwargs) # equivalent to foo(1, 2, 3, 4, a=3, b=4) +# you can pass args and kwargs along to other functions that take args/kwargs +# by expanding them with * and ** respectively +def pass_all_the_args(*args, **kwargs): + all_the_args(*args, **kwargs) + print varargs(*args) + print keyword_args(**kwargs) + # Function Scope x = 5 def setX(num): # Local var x not the same as global variable x x = num # => 43 - print (x) # => 43 + print x # => 43 def setGlobalX(num): global x - print (x) # => 5 + print x # => 5 x = num # global var x is now set to 6 - print (x) # => 6 + print x # => 6 setX(43) setGlobalX(6) @@ -442,11 +466,11 @@ filter(lambda x: x > 5, [3, 4, 5, 6, 7]) # => [6, 7] [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] + #################################################### ## 5. Classes #################################################### - # We subclass from object to get a class. class Human(object): @@ -516,6 +540,9 @@ from math import * # You can shorten module names import math as m math.sqrt(16) == m.sqrt(16) # => True +# you can also test that the functions are equivalent +from math import sqrt +math.sqrt == m.sqrt == sqrt # => True # Python modules are just ordinary python files. You # can write your own, and import them. The name of the @@ -542,8 +569,9 @@ def double_numbers(iterable): # double_numbers. # Note xrange is a generator that does the same thing range does. # Creating a list 1-900000000 would take lot of time and space to be made. -# xrange creates an xrange generator object instead of creating the entire list like range does. -# We use a trailing underscore in variable names when we want to use a name that +# xrange creates an xrange generator object instead of creating the entire list +# like range does. +# We use a trailing underscore in variable names when we want to use a name that # would normally collide with a python keyword xrange_ = xrange(1, 900000000) diff --git a/python3.html.markdown b/python3.html.markdown index 0b4feccc..6b1d3156 100644 --- a/python3.html.markdown +++ b/python3.html.markdown @@ -635,7 +635,6 @@ print(say(say_please=True)) # Can you buy me a beer? Please! I am poor :( * [The Official Docs](http://docs.python.org/3/) * [Hitchhiker's Guide to Python](http://docs.python-guide.org/en/latest/) -* [Python Module of the Week](http://pymotw.com/3/) * [A Crash Course in Python for Scientists](http://nbviewer.ipython.org/5920182) ### Dead Tree diff --git a/ru-ru/go-ru.html.markdown b/ru-ru/go-ru.html.markdown index 44a22b45..e06ae9bd 100644 --- a/ru-ru/go-ru.html.markdown +++ b/ru-ru/go-ru.html.markdown @@ -65,7 +65,7 @@ func beyondHello() { learnTypes() // < y minutes, learn more! } -// Функция имеющая входные параметры и возврат нескольких значений. +// Функция, имеющая входные параметры и возвращающая несколько значений. func learnMultiple(x, y int) (sum, prod int) { return x + y, x * y // Возврат двух значений. } diff --git a/ru-ru/java-ru.html.markdown b/ru-ru/java-ru.html.markdown index 460086e3..005495cc 100644 --- a/ru-ru/java-ru.html.markdown +++ b/ru-ru/java-ru.html.markdown @@ -181,7 +181,7 @@ public class LearnJavaRu { // Если они находятся перед переменной, сначала происходит // увеличение/уменьшение, затем операция, если после, // то сначала выполняется операция, затем увеличение/уменьшение. - System.out.println(i++); //i = 1, напечатает 0 (пре-инкремент) + System.out.println(i++); //i = 1, напечатает 0 (пост-инкремент) System.out.println(++i); //i = 2, напечатает 2 (пре-инкремент) System.out.println(i--); //i = 1, напечатает 2 (пост-декремент) System.out.println(--i); //i = 0, напечатает 0 (пре-декремент) diff --git a/ru-ru/lua-ru.html.markdown b/ru-ru/lua-ru.html.markdown new file mode 100644 index 00000000..6f515975 --- /dev/null +++ b/ru-ru/lua-ru.html.markdown @@ -0,0 +1,425 @@ +--- +language: lua +filename: learnlua-ru.lua +contributors: + - ["Tyler Neylon", "http://tylerneylon.com/"] +translators: + - ["Max Solomonov", "https://vk.com/solomonovmaksim"] + - ["Max Truhonin", "https://vk.com/maximmax42"] + - ["Konstantin Gromyko", "https://vk.com/id0x1765d79"] + - ["Stanislav Gromov", "https://vk.com/id156354391"] +lang: ru-ru +--- + +```lua +-- Два дефиса начинают однострочный комментарий. + +--[[ + Добавление двух квадратных скобок + делает комментарий многострочным. +--]] +-------------------------------------------------------------------------------- +-- 1. Переменные, циклы и условия. +-------------------------------------------------------------------------------- + +num = 42 -- Все числа имеют тип double. +-- Не волнуйтесь, в 64-битных double 52 бита +-- отведено под хранение целой части числа; +-- точность не является проблемой для +-- целочисленных значений, занимающих меньше 52 бит. + +s = 'walternate' -- Неизменные строки, как в Python. +t = "Двойные кавычки также приветствуются" +u = [[ Двойные квадратные скобки + начинают и заканчивают + многострочные значения.]] +t = nil -- Удаляет определение переменной t; в Lua есть сборка мусора. + +-- Блоки обозначаются ключевыми словами, такими как do/end: +while num < 50 do + num = num + 1 -- Операторов ++ и += нет. +end + +-- Ветвление "если": +if num > 40 then + print('больше 40') +elseif s ~= 'walternate' then -- ~= обозначает "не равно". + -- Проверка равенства это ==, как в Python; работает для строк. + io.write('не больше 40\n') -- По умолчанию вывод в stdout. +else + -- По умолчанию переменные являются глобальными. + thisIsGlobal = 5 -- Стиль CamelСase является общим. + + -- Как сделать переменную локальной: + local line = io.read() -- Считывает введённую строку. + + -- Для конкатенации строк используется оператор .. : + print('Зима пришла, ' .. line) +end + +-- Неопределённые переменные возвращают nil. +-- Этот пример не является ошибочным: +foo = anUnknownVariable -- Теперь foo = nil. + +aBoolValue = false + +-- Только значения nil и false являются ложными; 0 и '' являются истинными! +if not aBoolValue then print('это значение ложно') end + +-- Для 'or' и 'and' действует принцип "какой оператор дальше, +-- тот и применяется". Это действует аналогично оператору a?b:c в C/js: +ans = aBoolValue and 'yes' or 'no' --> 'no' + +karlSum = 0 +for i = 1, 100 do -- Здесь указан диапазон, ограниченный с двух сторон. + karlSum = karlSum + i +end + +-- Используйте "100, 1, -1" как нисходящий диапазон: +fredSum = 0 +for j = 100, 1, -1 do fredSum = fredSum + j end + +-- В основном, диапазон устроен так: начало, конец[, шаг]. + +-- Другая конструкция цикла: +repeat + print('путь будущего') + num = num - 1 +until num == 0 + +-------------------------------------------------------------------------------- +-- 2. Функции. +-------------------------------------------------------------------------------- + +function fib(n) + if n < 2 then return n end + return fib(n - 2) + fib(n - 1) +end + +-- Вложенные и анонимные функции являются нормой: +function adder(x) + -- Возращаемая функция создаётся, когда вызывается функция adder, + -- и запоминает значение переменной x: + return function (y) return x + y end +end +a1 = adder(9) +a2 = adder(36) +print(a1(16)) --> 25 +print(a2(64)) --> 100 + +-- Возвраты, вызовы функций и присвоения работают со списками, +-- которые могут иметь разную длину. +-- Лишние получатели принимают значение nil, а лишние значения игнорируются. + +x, y, z = 1, 2, 3, 4 +-- Теперь x = 1, y = 2, z = 3, а 4 просто отбрасывается. + +function bar(a, b, c) + print(a, b, c) + return 4, 8, 15, 16, 23, 42 +end + +x, y = bar('zaphod') --> выводит "zaphod nil nil" +-- Теперь x = 4, y = 8, а значения 15..42 отбрасываются. + +-- Функции могут быть локальными и глобальными. Эти строки делают одно и то же: +function f(x) return x * x end +f = function (x) return x * x end + +-- Эти тоже: +local function g(x) return math.sin(x) end +local g = function(x) return math.sin(x) end +-- Эквивалентно для local function g(x)..., однако ссылки на g +-- в теле функции не будут работать, как ожидалось. +local g; g = function (x) return math.sin(x) end +-- 'local g' будет прототипом функции. + +-- Кстати, тригонометрические функции работают с радианами. + +-- Вызов функции с одним строковым параметром не требует круглых скобок: +print 'hello' -- Работает без ошибок. + +-- Вызов функции с одним табличным параметром также +-- не требует круглых скобок (про таблицы в след. части): +print {} -- Тоже сработает. + +-------------------------------------------------------------------------------- +-- 3. Таблицы. +-------------------------------------------------------------------------------- + +-- Таблица = единственная составная структура данных в Lua; +-- представляет собой ассоциативный массив. +-- Подобно массивам в PHP или объектам в JS, они представляют собой +-- хеш-таблицы, которые также можно использовать в качестве списков. + + +-- Использование словарей: + +-- Литералы имеют ключ по умолчанию: +t = {key1 = 'value1', key2 = false} + +-- Строковые ключи используются, как в точечной нотации в JS: +print(t.key1) -- Печатает 'value1'. +t.newKey = {} -- Добавляет новую пару ключ/значение. +t.key2 = nil -- Удаляет key2 из таблицы. + +-- Литеральная нотация для любого значения ключа (кроме nil): +u = {['@!#'] = 'qbert', [{}] = 1729, [6.28] = 'tau'} +print(u[6.28]) -- пишет "tau" + +-- Ключ соответствует значению для чисел и строк, но при +-- использовании таблицы в качестве ключа берётся её экземпляр. +a = u['@!#'] -- Теперь a = 'qbert'. +b = u[{}] -- Вы могли ожидать 1729, но получится nil: +-- b = nil, т.к. ключ не будет найден. +-- Это произойдёт потому, что за ключ мы использовали не тот же самый объект, +-- который был использован для сохранения оригинального значения. +-- Поэтому строки и числа удобнее использовать в качестве ключей. + +-- Вызов функции с одной таблицей в качестве аргумента +-- не требует круглых скобок: +function h(x) print(x.key1) end +h{key1 = 'Sonmi~451'} -- Печатает 'Sonmi~451'. + +for key, val in pairs(u) do -- Цикл по таблице. + print(key, val) +end + +-- _G - это таблица со всеми глобалями. +print(_G['_G'] == _G) -- Печатает 'true'. + +-- Использование таблиц, как списков / массивов: + +-- Список значений с неявно заданными целочисленными ключами: +v = {'value1', 'value2', 1.21, 'gigawatts'} +for i = 1, #v do -- #v - размер списка v. + print(v[i]) -- Нумерация начинается с 1 !! +end + +-- Список не является отдельным типом. v - всего лишь таблица +-- с последовательными целочисленными ключами, воспринимаемая как список. + +-------------------------------------------------------------------------------- +-- 3.1 Метатаблицы и метаметоды. +-------------------------------------------------------------------------------- + +-- Таблицу можно связать с метатаблицей, задав ей поведение, как при +-- перегрузке операторов. Позже мы увидим, что метатаблицы поддерживают +-- поведение, как в js-прототипах. +f1 = {a = 1, b = 2} -- Представляет дробь a/b. +f2 = {a = 2, b = 3} + +-- Это не сработает: +-- s = f1 + f2 + +metafraction = {} +function metafraction.__add(f1, f2) + local sum = {} + sum.b = f1.b * f2.b + sum.a = f1.a * f2.b + f2.a * f1.b + return sum +end + +setmetatable(f1, metafraction) +setmetatable(f2, metafraction) + +s = f1 + f2 -- вызвать __add(f1, f2) на метатаблице от f1 + +-- f1, f2 не имеют ключа для своих метатаблиц в отличии от прототипов в js, +-- нужно получить его через getmetatable(f1). Метатаблица - обычная таблица +-- поэтому с ключами, известными для Lua (например, __add). + +-- Но следущая строка будет ошибочной т.к в s нет метатаблицы: +-- t = s + s +-- Похожий на классы подход, приведенный ниже, поможет это исправить. + +-- __index перегружает в метатаблице просмотр через точку: +defaultFavs = {animal = 'gru', food = 'donuts'} +myFavs = {food = 'pizza'} +setmetatable(myFavs, {__index = defaultFavs}) +eatenBy = myFavs.animal -- работает! спасибо, мета-таблица. + +-------------------------------------------------------------------------------- +-- При неудаче прямой табличный поиск попытается использовать +-- значение __index в метатаблице, причём это рекурсивно. + +-- Значение __index также может быть функцией +-- function(tbl, key) для настраиваемого поиска. + +-- Значения типа __index, __add, ... называются метаметодами. +-- Ниже приведён полный список метаметодов. + +-- __add(a, b) для a + b +-- __sub(a, b) для a - b +-- __mul(a, b) для a * b +-- __div(a, b) для a / b +-- __mod(a, b) для a % b +-- __pow(a, b) для a ^ b +-- __unm(a) для -a +-- __concat(a, b) для a .. b +-- __len(a) для #a +-- __eq(a, b) для a == b +-- __lt(a, b) для a < b +-- __le(a, b) для a <= b +-- __index(a, b) <функция или таблица> для a.b +-- __newindex(a, b, c) для a.b = c +-- __call(a, ...) для a(...) + +-------------------------------------------------------------------------------- +-- 3.2 Классоподобные таблицы и наследование. +-------------------------------------------------------------------------------- + +-- В Lua нет поддержки классов на уровне языка, +-- однако существуют разные способы их создания с помощью +-- таблиц и метатаблиц. + +-- Ниже приведён один из таких способов. + +Dog = {} -- 1. + +function Dog:new() -- 2. + local newObj = {sound = 'woof'} -- 3. + self.__index = self -- 4. + return setmetatable(newObj, self) -- 5. +end + +function Dog:makeSound() -- 6. + print('I say ' .. self.sound) +end + +mrDog = Dog:new() -- 7. +mrDog:makeSound() -- 'I say woof' -- 8. + +-- 1. Dog похоже на класс, но на самом деле это таблица. +-- 2. "function tablename:fn(...)" - то же самое, что и +-- "function tablename.fn(self, ...)", просто : добавляет первый аргумент +-- перед собой. См. пункты 7 и 8, чтобы понять, как self получает значение. +-- 3. newObj - это экземпляр класса Dog. +-- 4. "self" - экземпляр класса. Зачастую self = Dog, но с помощью наследования +-- это можно изменить. newObj получит свои функции, когда мы установим +-- метатаблицу для newObj и __index для self на саму себя. +-- 5. Напоминание: setmetatable возвращает первый аргумент. +-- 6. : работает, как в пункте 2, но в этот раз мы ожидаем, +-- что self будет экземпляром, а не классом. +-- 7. То же самое, что и Dog.new(Dog), поэтому self = Dog в new(). +-- 8. То же самое, что mrDog.makeSound(mrDog); self = mrDog. +-------------------------------------------------------------------------------- + +-- Пример наследования: + +LoudDog = Dog:new() -- 1. + +function LoudDog:makeSound() + local s = self.sound .. ' ' -- 2. + print(s .. s .. s) +end + +seymour = LoudDog:new() -- 3. +seymour:makeSound() -- 'woof woof woof' -- 4. + +-------------------------------------------------------------------------------- +-- 1. LoudDog получит методы и переменные класса Dog. +-- 2. В self будет ключ 'sound' из new(), см. пункт 3. +-- 3. То же самое, что и "LoudDog.new(LoudDog)", конвертированное +-- в "Dog.new(LoudDog)", поскольку в LoudDog нет ключа 'new', +-- но в его метатаблице есть "__index = Dog". +-- Результат: Метатаблицей для seymour стала LoudDog, +-- а "LoudDog.__index = Dog". Поэтому seymour.key будет равно +-- seymour.key, LoudDog.key, Dog.key, в зависимости от того, +-- какая таблица будет первой с заданным ключом. +-- 4. Ключ 'makeSound' находится в LoudDog; +-- то же самое, что и "LoudDog.makeSound(seymour)". + +-- При необходимости функция new() в подклассе +-- может быть похожа на аналог в базовом классе. +function LoudDog:new() + local newObj = {} + -- установить newObj + self.__index = self + return setmetatable(newObj, self) +end + +-------------------------------------------------------------------------------- +-- 4. Модули. +-------------------------------------------------------------------------------- + + +--[[ Я закомментировал этот раздел, чтобы остальная часть скрипта осталась +-- работоспособной. +``` + +```lua +-- Предположим, файл mod.lua будет выглядеть так: +local M = {} + +local function sayMyName() + print('Hrunkner') +end + +function M.sayHello() + print('Привет, ') + sayMyName() +end + +return M + +-- Другой файл может использовать функционал mod.lua: +local mod = require('mod') -- Запустим файл mod.lua. + +-- require - стандартный способ подключения модулей. +-- require ведёт себя так: (если не кэшировано, см. ниже) +local mod = (function () + <содержимое mod.lua> +end)() +-- Файл mod.lua воспринимается, как тело функции, поэтому +-- все локальные переменные и функции внутри него не видны за его пределами. + +-- Это работает, так как здесь mod = M в mod.lua: +mod.sayHello() -- Выведет "Привет, Hrunkner". + +-- Это будет ошибочным; sayMyName доступна только в mod.lua: +mod.sayMyName() -- ошибка + +-- Значения, возвращаемые require, кэшируются, +-- поэтому содержимое файла выполняется только 1 раз, +-- даже если он подключается с помощью require много раз. + +-- Предположим, mod2.lua содержит "print('Hi!')". +local a = require('mod2') -- Выведет "Hi!" +local b = require('mod2') -- Ничего не выведет; a=b. + +-- dofile, в отличии от require, работает без кэширования: +dofile('mod2') --> Hi! +dofile('mod2') --> Hi! (запустится снова) + +-- loadfile загружает файл, но не запускает его. +f = loadfile('mod2') -- Вызов f() запустит содержимое mod2.lua. + +-- loadstring - это loadfile для строк. +g = loadstring('print(343)') -- Вернет функцию. +g() -- Напишет 343. + +--]] + +``` +## Примечание (от автора) + +Мне было интересно изучить Lua, чтобы делать игры при помощи <a href="http://love2d.org/">игрового движка LÖVE</a>. + +Я начинал с <a href="http://nova-fusion.com/2012/08/27/lua-for-programmers-part-1/">BlackBulletIV's Lua for programmers</a>. +Затем я прочитал официальную <a href="http://www.lua.org/pil/contents.html">Документацию по Lua</a>. + +Также может быть полезной <a href="http://lua-users.org/files/wiki_insecure/users/thomasl/luarefv51.pdf">Краткая справка по Lua</a> на lua-users.org. + +Ещё из основных тем не охвачены стандартные библиотеки: + +* <a href="http://lua-users.org/wiki/StringLibraryTutorial">библиотека string</a> +* <a href="http://lua-users.org/wiki/TableLibraryTutorial">библиотека table</a> +* <a href="http://lua-users.org/wiki/MathLibraryTutorial">библиотека math</a> +* <a href="http://lua-users.org/wiki/IoLibraryTutorial">библиотека io</a> +* <a href="http://lua-users.org/wiki/OsLibraryTutorial">библиотека os</a> + +Кстати, весь файл написан на Lua; сохраните его как learn.lua и запустите при помощи "lua learn.lua" ! + +Изначально эта статья была написана для tylerneylon.com. +Также она доступна как <a href="https://gist.github.com/tylerneylon/5853042">github gist</a>. Удачи с Lua! diff --git a/ruby.html.markdown b/ruby.html.markdown index e58c513d..7cf5bdc7 100644 --- a/ruby.html.markdown +++ b/ruby.html.markdown @@ -518,5 +518,5 @@ Something.new.qux # => 'qux' - [Learn Ruby by Example with Challenges](http://www.learneroo.com/modules/61/nodes/338) - A variant of this reference with in-browser challenges. - [Official Documentation](http://www.ruby-doc.org/core-2.1.1/) - [Ruby from other languages](https://www.ruby-lang.org/en/documentation/ruby-from-other-languages/) -- [Programming Ruby](http://www.amazon.com/Programming-Ruby-1-9-2-0-Programmers/dp/1937785491/) - An older [free addition](http://ruby-doc.com/docs/ProgrammingRuby/) is available online. +- [Programming Ruby](http://www.amazon.com/Programming-Ruby-1-9-2-0-Programmers/dp/1937785491/) - An older [free edition](http://ruby-doc.com/docs/ProgrammingRuby/) is available online. - [Ruby Style Guide](https://github.com/bbatsov/ruby-style-guide) - A community-driven Ruby coding style guide. diff --git a/scala.html.markdown b/scala.html.markdown index dc039f0c..61c735e3 100644 --- a/scala.html.markdown +++ b/scala.html.markdown @@ -54,14 +54,17 @@ var y = 10 y = 20 // y is now 20 /* - Scala is a statically typed language, yet note that in the above declarations, we did not specify - a type. This is due to a language feature called type inference. In most cases, Scala compiler can - guess what the type of a variable is, so you don't have to type it every time. We can explicitly - declare the type of a variable like so: + Scala is a statically typed language, yet note that in the above declarations, + we did not specify a type. This is due to a language feature called type + inference. In most cases, Scala compiler can guess what the type of a variable + is, so you don't have to type it every time. We can explicitly declare the + type of a variable like so: */ val z: Int = 10 val a: Double = 1.0 -val b: Double = 10 // Notice automatic conversion from Int to Double, result is 10.0, not 10 + +// Notice automatic conversion from Int to Double, result is 10.0, not 10 +val b: Double = 10 // Boolean values true @@ -94,8 +97,8 @@ true == false // false This means the result of evaluating 1 + 7 is an object of type Int with a value of 8 - Note that "res29" is a sequentially generated variable name to store the results of the - expressions you typed, your output may differ. + Note that "res29" is a sequentially generated variable name to store the + results of the expressions you typed, your output may differ. */ "Scala strings are surrounded by double quotes" @@ -142,27 +145,71 @@ val html = """<form id="daform"> // 2. Functions ///////////////////////////////////////////////// -// The next line gives you a function that takes an Int and returns it squared -(x:Int) => x * x +// Functions are defined like so: +// +// def functionName(args...): ReturnType = { body... } +// +// If you come from more traditional languages, notice the omission of the +// return keyword. In Scala, the last expression in the function block is the +// return value. +def sumOfSquares(x: Int, y: Int): Int = { + val x2 = x * x + val y2 = y * y + x2 + y2 +} -// You can assign this function to an identifier, like this: -val sq = (x:Int) => x * x +// The { } can be omitted if the function body is a single expression: +def sumOfSquaresShort(x: Int, y: Int): Int = x * x + y * y -/* The above says this +// Syntax for calling functions is familiar: +sumOfSquares(3, 4) // => 25 - sq: Int => Int = <function1> +// In most cases (with recursive functions the most notable exception), function +// return type can be omitted, and the same type inference we saw with variables +// will work with function return values: +def sq(x: Int) = x * x // Compiler can guess return type is Int - Which means that this time we gave an explicit name to the value - sq is a - function that take an Int and returns Int. +// Functions can have default parameters: +def addWithDefault(x: Int, y: Int = 5) = x + y +addWithDefault(1, 2) // => 3 +addWithDefault(1) // => 6 - sq can be executed as follows: -*/ -sq(10) // Gives you this: res33: Int = 100. +// Anonymous functions look like this: +(x:Int) => x * x -// The colon explicitly defines the type of a value, in this case a function -// taking an Int and returning an Int. -val add10: Int => Int = _ + 10 +// Unlike defs, even the input type of anonymous functions can be omitted if the +// context makes it clear. Notice the type "Int => Int" which means a function +// that takes Int and returns Int. +val sq: Int => Int = x => x * x + +// Anonymous functions can be called as usual: +sq(10) // => 100 + +// If your anonymous function has one or two arguments, and each argument is +// used only once, Scala gives you an even shorter way to define them. These +// anonymous functions turn out to be extremely common, as will be obvious in +// the data structure section. +val addOne: Int => Int = _ + 1 +val weirdSum: (Int, Int) => Int = (_ * 2 + _ * 3) + +addOne(5) // => 6 +weirdSum(2, 4) // => 16 + + +// The return keyword exists in Scala, but it only returns from the inner-most +// def that surrounds it. +// WARNING: Using return in Scala is error-prone and should be avoided. +// It has no effect on anonymous functions. For example: +def foo(x: Int): Int = { + val anonFunc: Int => Int = { z => + if (z > 5) + return z // This line makes z the return value of foo! + else + z + 2 // This line is the return value of anonFunc + } + anonFunc(x) // This line is the return value of foo +} ///////////////////////////////////////////////// @@ -187,7 +234,7 @@ while (i < 10) { println("i " + i); i+=1 } // Yes, again. What happened? Why i // Show the value of i. Note that while is a loop in the classical sense - // it executes sequentially while changing the loop variable. while is very - // fast, faster that Java // loops, but using the combinators and + // fast, faster that Java loops, but using the combinators and // comprehensions above is easier to understand and parallelize // A do while loop @@ -290,13 +337,24 @@ d._2 And now we will explain what these are. */ +// classes are similar to classes in other languages. Constructor arguments are +// declared after the class name, and initialization is done in the class body. class Dog(br: String) { + // Constructor code here var breed: String = br - //A method called bark, returning a String - def bark: String = { - // the body of the method - "Woof, woof!" - } + + // Define a method called bark, returning a String + def bark = "Woof, woof!" + + // Values and methods are assumed public. "protected" and "private" keywords + // are also available. + 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 class Dog(...) { ... } + // def chaseAfter(what: String): String } val mydog = new Dog("greyhound") @@ -304,58 +362,100 @@ println(mydog.breed) // => "greyhound" println(mydog.bark) // => "Woof, woof!" -// Classes can contain nearly any other construct, including other classes, -// functions, methods, objects, case classes, traits etc. +// The "object" keyword creates a type AND a singleton instance of it. It is +// common for Scala classes to have a "companion object", where the per-instance +// behavior is captured in the classes themselves, but behavior related to all +// instance of that class go in objects. The difference is similar to class +// methods vs static methods in other languages. Note that objects and classes +// can have the same name. +object Dog { + def allKnownBreeds = List("pitbull", "shepherd", "retriever") + def createDog(breed: String) = new Dog(breed) +} + + +// Case classes are classes that have extra functionality built in. A common +// question for Scala beginners is when to use classes and when to use case +// classes. The line is quite fuzzy, but in general, classes tend to focus on +// encapsulation, polymorphism, and behavior. The values in these classes tend +// to be private, and only methods are exposed. The primary purpose of case +// classes is to hold immutable data. They often have few methods, and the +// methods rarely have side-effects. +case class Person(name: String, phoneNumber: String) + +// Create a new instance. Note cases classes don't need "new" +val george = Person("George", "1234") +val kate = Person("Kate", "4567") + +// With case classes, you get a few perks for free, like getters: +george.phoneNumber // => "1234" -// Case classes +// Per field equality (no need to override .equals) +Person("George", "1234") == Person("Kate", "1236") // => false -case class Person(name:String, phoneNumber:String) +// Easy way to copy +// otherGeorge == Person("george", "9876") +val otherGeorge = george.copy(phoneNumber = "9876") -Person("George", "1234") == Person("Kate", "1236") +// And many others. Case classes also get pattern matching for free, see below. -// Objects and traits coming soon! +// Traits coming soon! ///////////////////////////////////////////////// // 6. Pattern Matching ///////////////////////////////////////////////// -val me = Person("George", "1234") +// Pattern matching is a powerful and commonly used feature in Scala. Here's how +// you pattern match a case class. NB: Unlike other languages, Scala cases do +// not need breaks, fall-through does not happen. -me match { case Person(name, number) => { - "We matched someone : " + name + ", phone : " + number }} - -me match { case Person(name, number) => "Match : " + name; case _ => "Hm..." } +def matchPerson(person: Person): String = person match { + // Then you specify the patterns: + case Person("George", number) => "We found George! His number is " + number + case Person("Kate", number) => "We found Kate! Her number is " + number + case Person(name, number) => "We matched someone : " + name + ", phone : " + number +} -me match { case Person("George", number) => "Match"; case _ => "Hm..." } +val email = "(.*)@(.*)".r // Define a regex for the next example. -me match { case Person("Kate", number) => "Match"; case _ => "Hm..." } +// 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 +// more: +def matchEverything(obj: Any): String = obj match { + // You can match values: + case "Hello world" => "Got the string Hello world" -me match { case Person("Kate", _) => "Girl"; case Person("George", _) => "Boy" } + // You can match by type: + case x: Double => "Got a Double: " + x -val kate = Person("Kate", "1234") + // You can specify conditions: + case x: Int if x > 10000 => "Got a pretty big number!" -kate match { case Person("Kate", _) => "Girl"; case Person("George", _) => "Boy" } + // You can match case classes as before: + case Person(name, number) => s"Got contact info for $name!" + // You can match regular expressions: + case email(name, domain) => s"Got email address $name@$domain" + // You can match tuples: + case (a: Int, b: Double, c: String) => s"Got a tuple: $a, $b, $c" -// Regular expressions -val email = "(.*)@(.*)".r // Invoking r on String makes it a Regex -val serialKey = """(\d{5})-(\d{5})-(\d{5})-(\d{5})""".r // Using verbatim (multiline) syntax + // You can match data structures: + case List(1, b, c) => s"Got a list with three elements and starts with 1: 1, $b, $c" -val matcher = (value: String) => { - println(value match { - case email(name, domain) => s"It was an email: $name" - case serialKey(p1, p2, p3, p4) => s"Serial key: $p1, $p2, $p3, $p4" - case _ => s"No match on '$value'" // default if no match found - }) + // You can nest patterns: + case List(List((1, 2,"YAY"))) => "Got a list of list of tuple" } -matcher("mrbean@pyahoo.com") // => "It was an email: mrbean" -matcher("nope..") // => "No match on 'nope..'" -matcher("52917") // => "No match on '52917'" -matcher("52752-16432-22178-47917") // => "Serial key: 52752, 16432, 22178, 47917" +// In fact, you can pattern match any object with an "unapply" method. This +// feature is so powerful that Scala lets you define whole functions as +// patterns: +val patternFunc: Person => String = { + case Person("George", number") => s"George's number: $number" + case Person(name, number) => s"Random person's number: $number" +} ///////////////////////////////////////////////// @@ -392,7 +492,7 @@ sSquared.reduce (_+_) // The filter function takes a predicate (a function from A -> Boolean) and // selects all elements which satisfy the predicate List(1, 2, 3) filter (_ > 2) // List(3) -case class Person(name:String, phoneNumber:String) +case class Person(name:String, age:Int) List( Person(name = "Dom", age = 23), Person(name = "Bob", age = 30) @@ -423,7 +523,60 @@ for { n <- s; nSquared = n * n if nSquared < 10} yield nSquared // 8. Implicits ///////////////////////////////////////////////// -Coming soon! +/* WARNING WARNING: Implicits are a set of powerful features of Scala, and + * therefore it is easy to abuse them. Beginners to Scala should resist the + * temptation to use them until they understand not only how they work, but also + * best practices around them. We only include this section in the tutorial + * because they are so commonplace in Scala libraries that it is impossible to + * do anything meaningful without using a library that has implicits. This is + * meant for you to understand and work with implicts, not declare your own. + */ + +// Any value (vals, functions, objects, etc) can be declared to be implicit by +// using the, you guessed it, "implicit" keyword. Note we are using the Dog +// class from section 5 in these examples. +implicit val myImplicitInt = 100 +implicit def myImplicitFunction(breed: String) = new Dog("Golden " + breed) + +// By itself, implicit keyword doesn't change the behavior of the value, so +// above values can be used as usual. +myImplicitInt + 2 // => 102 +myImplicitFunction("Pitbull").breed // => "Golden Pitbull" + +// The difference is that these values are now eligible to be used when another +// piece of code "needs" an implicit value. One such situation is implicit +// function arguments: +def sendGreetings(toWhom: String)(implicit howMany: Int) = + s"Hello $toWhom, $howMany blessings to you and yours!" + +// If we supply a value for "howMany", the function behaves as usual +sendGreetings("John")(1000) // => "Hello John, 1000 blessings to you and yours!" + +// But if we omit the implicit parameter, an implicit value of the same type is +// used, in this case, "myImplicitInt": +sendGreetings("Jane") // => "Hello Jane, 100 blessings to you and yours!" + +// Implicit function parameters enable us to simulate type classes in other +// functional languages. It is so often used that it gets its own shorthand. The +// following two lines mean the same thing: +def foo[T](implicit c: C[T]) = ... +def foo[T : C] = ... + + +// Another situation in which the compiler looks for an implicit is if you have +// obj.method(...) +// but "obj" doesn't have "method" as a method. In this case, if there is an +// implicit conversion of type A => B, where A is the type of obj, and B has a +// method called "method", that conversion is applied. So having +// myImplicitFunction above in scope, we can say: +"Retriever".breed // => "Golden Retriever" +"Sheperd".bark // => "Woof, woof!" + +// Here the String is first converted to Dog using our function above, and then +// the appropriate method is called. This is an extremely powerful feature, but +// again, it is not to be used lightly. In fact, when you defined the implicit +// function above, your compiler should have given you a warning, that you +// shouldn't do this unless you really know what you're doing. ///////////////////////////////////////////////// diff --git a/swift.html.markdown b/swift.html.markdown index 005e511c..0d1d2df4 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -6,7 +6,7 @@ contributors: filename: learnswift.swift --- -Swift is a programming language for iOS and OS X development created by Apple. Designed to coexist with Objective-C and to be more resilient against erroneous code, Swift was introduced in 2014 at Apple's developer conference WWDC. It is built with the LLVM compiler included in Xcode 6 beta. +Swift is a programming language for iOS and OS X development created by Apple. Designed to coexist with Objective-C and to be more resilient against erroneous code, Swift was introduced in 2014 at Apple's developer conference WWDC. It is built with the LLVM compiler included in Xcode 6+. The official [Swift Programming Language](https://itunes.apple.com/us/book/swift-programming-language/id881256329) book from Apple is now available via iBooks. @@ -23,7 +23,7 @@ import UIKit // Xcode supports landmarks to annotate your code and lists them in the jump bar // MARK: Section mark // TODO: Do something soon -// FIXME Fix this code +// FIXME: Fix this code println("Hello, world") @@ -55,8 +55,8 @@ println("Build value: \(buildValue)") // Build value: 7 /* Optionals are a Swift language feature that allows you to store a `Some` or `None` value. - - Because Swift requires every property to have a value, even nil must be + + Because Swift requires every property to have a value, even nil must be explicitly stored as an Optional value. Optional<T> is an enum. @@ -94,7 +94,8 @@ var anyObjectVar: AnyObject = 7 anyObjectVar = "Changed value to a string, not good practice, but possible." /* -Comment here + Comment here + /* Nested comments are also supported */ @@ -112,8 +113,9 @@ Comment here // Array var shoppingList = ["catfish", "water", "lemons"] shoppingList[1] = "bottle of water" -let emptyArray = [String]() // immutable -var emptyMutableArray = [String]() // mutable +let emptyArray = [String]() // let == immutable +let emptyArray2 = Array<String>() // same as above +var emptyMutableArray = [String]() // var == mutable // Dictionary @@ -122,8 +124,9 @@ var occupations = [ "kaylee": "Mechanic" ] occupations["Jayne"] = "Public Relations" -let emptyDictionary = [String: Float]() // immutable -var emptyMutableDictionary = [String: Float]() // mutable +let emptyDictionary = [String: Float]() // let == immutable +let emptyDictionary2 = Dictionary<String, Float>() // same as above +var emptyMutableDictionary = [String: Float]() // var == mutable // @@ -165,14 +168,16 @@ do { } while 1 == 2 // Switch +// Very powerful, think `if` statements with syntax candy +// They support String, object instances, and primitives (Int, Double, etc) let vegetable = "red pepper" switch vegetable { case "celery": let vegetableComment = "Add some raisins and make ants on a log." case "cucumber", "watercress": let vegetableComment = "That would make a good tea sandwich." -case let x where x.hasSuffix("pepper"): - let vegetableComment = "Is it a spicy \(x)?" +case let localScopeValue where localScopeValue.hasSuffix("pepper"): + let vegetableComment = "Is it a spicy \(localScopeValue)?" default: // required (in order to cover all possible input) let vegetableComment = "Everything tastes good in soup." } @@ -186,21 +191,28 @@ default: // required (in order to cover all possible input) // in functions and can be passed around // Function with Swift header docs (format as reStructedText) + /** -A greet operation + A greet operation -- A bullet in docs -- Another bullet in the docs + - A bullet in docs + - Another bullet in the docs -:param: name A name -:param: day A day -:returns: A string containing the name and day value. + :param: name A name + :param: day A day + :returns: A string containing the name and day value. */ func greet(name: String, day: String) -> String { return "Hello \(name), today is \(day)." } greet("Bob", "Tuesday") +// similar to above except for the function parameter behaviors +func greet2(#requiredName: String, externalParamName localParamName: String) -> String { + return "Hello \(requiredName), the day is \(localParamName)" +} +greet2(requiredName:"John", externalParamName: "Sunday") + // Function that returns multiple items in a tuple func getGasPrices() -> (Double, Double, Double) { return (3.59, 3.69, 3.79) @@ -281,7 +293,7 @@ print(numbers) // [3, 6, 18] // Structures and classes have very similar capabilites struct NamesTable { - let names: [String] + let names = [String]() // Custom subscript subscript(index: Int) -> String { @@ -291,8 +303,8 @@ struct NamesTable { // Structures have an auto-generated (implicit) designated initializer let namesTable = NamesTable(names: ["Me", "Them"]) -//let name = namesTable[2] -//println("Name is \(name)") // Name is Them +let name = namesTable[1] +println("Name is \(name)") // Name is Them // // MARK: Classes @@ -341,7 +353,7 @@ internal class Rect: Shape { init(sideLength: Int) { self.sideLength = sideLength - // always super.init last when init custom properties + // always super.init last when init custom properties super.init() } @@ -368,6 +380,9 @@ print(mySquare.getArea()) // 25 mySquare.shrink() print(mySquare.sideLength) // 4 +// cast instance +let aShape = mySquare as Shape + // compare instances, not the same as == which compares objects (equal to) if mySquare === mySquare { println("Yep, it's mySquare") @@ -393,6 +408,17 @@ enum Suit { } } +// Enum values allow short hand syntax, no need to type the enum type +// when the variable is explicitly declared +var suitValue: Suit = .Hearts + +// Non-Integer enums require direct raw value assignments +enum BookName: String { + case John = "John" + case Luke = "Luke" +} +println("Name: \(BookName.John.rawValue)") + // // MARK: Protocols @@ -490,5 +516,4 @@ println(mySquare.sideLength) // 4 // change side length using custom !!! operator, increases size by 3 !!!mySquare println(mySquare.sideLength) // 12 - ``` diff --git a/tcl.html.markdown b/tcl.html.markdown new file mode 100755 index 00000000..f2d92fcd --- /dev/null +++ b/tcl.html.markdown @@ -0,0 +1,447 @@ +--- +language: Tcl +contributors: + - ["Poor Yorick", "http://pooryorick.com/"] +filename: learntcl.tcl +--- + +Tcl was created by [John Ousterhout](http://wiki.tcl.tk/John Ousterout) as a +reusable scripting language for chip design tools he was creating. In 1997 he +was awarded the [ACM Software System +Award](http://en.wikipedia.org/wiki/ACM_Software_System_Award) for Tcl. Tcl +can be used both as an embeddable scripting language and as a general +programming language. It can also be used as a portable C library, even in +cases where no scripting capability is needed, as it provides data structures +such as dynamic strings, lists, and hash tables. The C library also provides +portable functionality for loading dynamic libraries, string formatting and +code conversion, filesystem operations, network operations, and more. +Various features of Tcl stand out: + +* Convenient cross-platform networking API + +* Fully virtualized filesystem + +* Stackable I/O channels + +* Asynchronous to the core + +* Full coroutines + +* A threading model recognized as robust and easy to use + + +If Lisp is a list processor, then Tcl is a string processor. All values are +strings. A list is a string format. A procedure definition is a string +format. To achieve performance, Tcl internally caches structured +representations of these values. The list commands, for example, operate on +the internal cached representation, and Tcl takes care of updating the string +representation if it is ever actually needed in the script. The copy-on-write +design of Tcl allows script authors can pass around large data values without +actually incurring additional memory overhead. Procedures are automatically +byte-compiled unless they use the more dynamic commands such as "uplevel", +"upvar", and "trace". + +Tcl is a pleasure to program in. It will appeal to hacker types who find Lisp, +Forth, or Smalltalk interesting, as well as to engineers and scientists who +just want to get down to business with a tool that bends to their will. Its +discipline of exposing all programmatic functionality as commands, including +things like loops and mathematical operations that are usually baked into the +syntax of other languages, allows it to fade into the background of whatever +domain-specific functionality a project needs. It's syntax, which is even +lighter that that of Lisp, just gets out of the way. + + + + + +```tcl +#! /bin/env tclsh + +################################################################################ +## 1. Guidelines +################################################################################ + +# Tcl is not Bash or C! This needs to be said because standard shell quoting +# habits almost work in Tcl and it is common for people to pick up Tcl and try +# to get by with syntax they know from another language. It works at first, +# but soon leads to frustration with more complex scripts. + +# Braces are just a quoting mechanism, not a code block constructor or a list +# constructor. Tcl doesn't have either of those things. Braces are used, +# though, to escape special characters in procedure bodies and in strings that +# are formatted as lists. + + +################################################################################ +## 2. Syntax +################################################################################ + +# Every line is a command. The first word is the name of the command, and +# subsequent words are arguments to the command. Words are delimited by +# whitespace. Since every word is a string, in the simple case no special +# markup such as quotes, braces, or backslash, is necessary. Even when quotes +# are used, they are not a string constructor, but just another escaping +# character. + +set greeting1 Sal +set greeting2 ut +set greeting3 ations + + +#semicolon also delimits commands +set greeting1 Sal; set greeting2 ut; set greeting3 ations + + +# Dollar sign introduces variable substitution +set greeting $greeting1$greeting2$greeting3 + + +# Bracket introduces command substitution. The result of the command is +# substituted in place of the bracketed script. When the "set" command is +# given only the name of a variable, it returns the value of that variable. +set greeting $greeting1$greeting2[set greeting3] + + +# Command substitution should really be called script substitution, because an +# entire script, not just a command, can be placed between the brackets. The +# "incr" command increments the value of a variable and returns its value. +set greeting $greeting[ + incr i + incr i + incr i +] + + +# backslash suppresses the special meaning of characters +set amount \$16.42 + + +# backslash adds special meaning to certain characters +puts lots\nof\n\n\n\n\n\nnewlines + + +# A word enclosed in braces is not subject to any special interpretation or +# substitutions, except that a backslash before a brace is not counted when look#ing for the closing brace +set somevar { + This is a literal $ sign, and this \} escaped + brace remains uninterpreted +} + + +# In a word enclosed in double quotes, whitespace characters lose their special +# meaning +set name Neo +set greeting "Hello, $name" + + +#variable names can be any string +set {first name} New + + +# The brace form of variable substitution handles more complex variable names +set greeting "Hello, ${first name}" + + +# The "set" command can always be used instead of variable substitution +set greeting "Hello, [set {first name}]" + + +# To promote the words within a word to individual words of the current +# command, use the expansion operator, "{*}". +set {*}{name Neo} + +# is equivalent to +set name Neo + + +# An array is a special variable that is a container for other variables. +set person(name) Neo +set person(gender) male +set greeting "Hello, $person(name)" + + +# A namespace holds commands and variables +namespace eval people { + namespace eval person1 { + set name Neo + } +} + + +#The full name of a variable includes its enclosing namespace(s), delimited by two colons: +set greeting "Hello $people::person::name" + + + +################################################################################ +## 3. A Few Notes +################################################################################ + +# All other functionality is implemented via commands. From this point on, +# there is no new syntax. Everything else there is to learn about Tcl is about +# the behaviour of individual commands, and what meaning they assign to their +# arguments. + + +# To end up with an interpreter that can do nothing, delete the global +# namespace. It's not very useful to do such a thing, but it illustrates the +# nature of Tcl. +namespace delete :: + + +# Because of name resolution behaviour, its safer to use the "variable" command to declare or to assign a value to a namespace. +namespace eval people { + namespace eval person1 { + variable name Neo + } +} + + +# The full name of a variable can always be used, if desired. +set people::person1::name Neo + + + +################################################################################ +## 4. Commands +################################################################################ + +# Math can be done with the "expr" command. +set a 3 +set b 4 +set c [expr {$a + $b}] + +# Since "expr" performs variable substitution on its own, brace the expression +# to prevent Tcl from performing variable substitution first. See +# "http://wiki.tcl.tk/Brace%20your%20#%20expr-essions" for details. + + +# The "expr" command understands variable and command substitution +set c [expr {$a + [set b]}] + + +# The "expr" command provides a set of mathematical functions +set c [expr {pow($a,$b)}] + + +# Mathematical operators are available as commands in the ::tcl::mathop +# namespace +::tcl::mathop::+ 5 3 + +# Commands can be imported from other namespaces +namespace import ::tcl::mathop::+ +set result [+ 5 3] + + +# New commands can be created via the "proc" command. +proc greet name { + return "Hello, $name!" +} + +#multiple parameters can be specified +proc greet {greeting name} { + return "$greeting, $name!" +} + + +# As noted earlier, braces do not construct a code block. Every value, even +# the third argument of the "proc" command, is a string. The previous command +# rewritten to not use braces at all: +proc greet greeting\ name return\ \"Hello,\ \$name! + + + +# When the last parameter is the literal value, "args", it collects all extra +# arguments when the command is invoked +proc fold {cmd args} { + set res 0 + foreach arg $args { + set res [cmd $res $arg] + } +} +fold ::tcl::mathop::* 5 3 3 ;# -> 45 + + +# Conditional execution is implemented as a command +if {3 > 4} { + puts {This will never happen} +} elseif {4 > 4} { + puts {This will also never happen} +} else { + puts {This will always happen} +} + + +# Loops are implemented as commands. The first, second, and third +# arguments of the "for" command are treated as mathematical expressions +for {set i 0} {$i < 10} {incr i} { + set res [expr {$res + $i}] +} + + +# The first argument of the "while" command is also treated as a mathematical +# expression +set i 0 +while {$i < 10} { + incr i 2 +} + + +# A list is a specially-formatted string. In the simple case, whitespace is sufficient to delimit values +set amounts 10\ 33\ 18 +set amount [lindex $amounts 1] + + +# Braces and backslash can be used to format more complex values in a list. A +# list looks exactly like a script, except that the newline character and the +# semicolon character lose their special meanings. This feature makes Tcl +# homoiconic. There are three items in the following list. +set values { + + one\ two + + {three four} + + five\{six + +} + + +# Since a list is a string, string operations could be performed on it, at the +# risk of corrupting the formatting of the list. +set values {one two three four} +set values [string map {two \{} $values] ;# $values is no-longer a \ + properly-formatted listwell-formed list + + +# The sure-fire way to get a properly-formmated list is to use "list" commands +set values [list one \{ three four] +lappend values { } ;# add a single space as an item in the list + + +# Use "eval" to evaluate a value as a script +eval { + set name Neo + set greeting "Hello, $name" +} + + +# A list can always be passed to "eval" as a script composed of a single +# command. +eval {set name Neo} +eval [list set greeting "Hello, $name"] + + +# Therefore, when using "eval", use [list] to build up a desired command +set command {set name} +lappend command {Archibald Sorbisol} +eval $command + + +# A common mistake is not to use list functions when building up a command +set command {set name} +append command { Archibald Sorbisol} +eval $command ;# There is an error here, because there are too many arguments \ + to "set" in {set name Archibald Sorbisol} + + +# This mistake can easily occur with the "subst" command. +set replacement {Archibald Sorbisol} +set command {set name $replacement} +set command [subst $command] +eval $command ;# The same error as before: to many arguments to "set" in \ + {set name Archibald Sorbisol} + + +# The proper way is to format the substituted value using use the "list" +# command. +set replacement [list {Archibald Sorbisol}] +set command {set name $replacement} +set command [subst $command] +eval $command + + +# It is extremely common to see the "list" command being used to properly +# format values that are substituted into Tcl script templates. There are +# several examples of this, below. + + +# The "apply" command evaluates a string as a command. +set cmd {{greeting name} { + return "$greeting, $name!" +}} +apply $cmd Whaddup Neo + + +# The "uplevel" command evaluates a script in some enclosing scope. +proc greet {} { + uplevel {puts "$greeting, $name"} +} + +proc set_double {varname value} { + if {[string is double $value]} { + uplevel [list variable $varname $value] + } else { + error [list {not a double} $value] + } +} + + +# The "upvar" command links a variable in the current scope to a variable in +# some enclosing scope +proc set_double {varname value} { + if {[string is double $value]} { + upvar 1 $varname var + set var $value + } else { + error [list {not a double} $value] + } +} + + +#get rid of the built-in "while" command. +rename ::while {} + + +# Define a new while command with the "proc" command. More sophisticated error +# handling is left as an exercise. +proc while {condition script} { + if {[uplevel 1 [list expr $condition]]} { + uplevel 1 $script + tailcall [namespace which while] $condition $script + } +} + + +# The "coroutine" command creates a separate call stack, along with a command +# to enter that call stack. The "yield" command suspends execution in that +# stack. +proc countdown {} { + #send something back to the initial "coroutine" command + yield + + set count 3 + while {$count > 1} { + yield [incr count -1] + } + return 0 +} +coroutine countdown1 countdown +coroutine countdown2 countdown +puts [countdown 1] ;# -> 2 +puts [countdown 2] ;# -> 2 +puts [countdown 1] ;# -> 1 +puts [countdown 1] ;# -> 0 +puts [coundown 1] ;# -> invalid command name "countdown1" +puts [countdown 2] ;# -> 1 + + +``` + +## Reference + +[Official Tcl Documentation](http://www.tcl.tk/man/tcl/) + +[Tcl Wiki](http://wiki.tcl.tk) + +[Tcl Subreddit](http://www.reddit.com/r/Tcl) diff --git a/zh-cn/lua-cn.html.markdown b/zh-cn/lua-cn.html.markdown index 53a603a2..098d0ab5 100644 --- a/zh-cn/lua-cn.html.markdown +++ b/zh-cn/lua-cn.html.markdown @@ -63,8 +63,8 @@ foo = anUnknownVariable -- 现在 foo = nil. aBoolValue = false ---只有nil和false为假; 0和 ''都均为真！ -if not aBoolValue then print('twas false') end +--只有nil和false为假; 0和 ''均为真！ +if not aBoolValue then print('false') end -- 'or'和 'and'短路 -- 类似于C/js里的 a?b:c 操作符： @@ -149,7 +149,7 @@ print {} -- 一样可以工作。 -- Table = Lua唯一的组合数据结构; -- 它们是关联数组。 -- 类似于PHP的数组或者js的对象， --- 它们是哈希表或者字典，也可以当初列表使用。 +-- 它们是哈希表或者字典，也可以当列表使用。 -- 按字典/map的方式使用Table： diff --git a/zh-cn/markdown-cn.html.markdown b/zh-cn/markdown-cn.html.markdown index eecb8c5b..1c577efb 100644 --- a/zh-cn/markdown-cn.html.markdown +++ b/zh-cn/markdown-cn.html.markdown @@ -1,5 +1,5 @@ --- -language: Markdown +language: markdown contributors: - ["Dan Turkel", "http://danturkel.com/"] translators: |