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diff --git a/citron.html.markdown b/citron.html.markdown new file mode 100644 index 00000000..bd3c398c --- /dev/null +++ b/citron.html.markdown @@ -0,0 +1,212 @@ +--- +language: citron +filename: learncitron.ctr +contributors: + - ["AnotherTest", ""] +lang: en-us +--- +```ruby +# Comments start with a '#' +# All comments encompass a single line + +########################################### +## 1. Primitive Data types and Operators +########################################### + +# You have numbers +3. # 3 + +# Numbers are all doubles in interpreted mode + +# Mathematical operator precedence is not respected. +# binary 'operators' are evaluated in ltr order +1 + 1. # 2 +8 - 4. # 4 +10 + 2 * 3. # 36 + +# Division is always floating division +35 / 2 # 17.5. + +# Integer division is non-trivial, you may use floor +(35 / 2) floor # 17. + +# Booleans are primitives +True. +False. + +# Boolean messages +True not. # False +False not. # True +1 = 1. # True +1 !=: 1. # False +1 < 10. # True + +# Here, `not` is a unary message to the object `Boolean` +# Messages are comparable to instance method calls +# And they have three different forms: +# 1. Unary messages: Length > 1, and they take no arguments: + False not. +# 2. Binary Messages: Length = 1, and they take a single argument: + False & True. +# 3. Keyword messages: must have at least one ':', they take as many arguments +# as they have `:` s + False either: 1 or: 2. # 2 + +# Strings +'This is a string'. +'There are no character types exposed to the user'. +# "You cannot use double quotes for strings" <- Error + +# Strins can be summed +'Hello, ' + 'World!'. # 'Hello, World!' + +# Strings allow access to their characters +'This is a beautiful string' at: 0. # 'T' + +########################################### +## intermission: Basic Assignment +########################################### + +# You may assign values to the current scope: +var name is value. # assignes `value` into `name` + +# You may also assign values into the current object's namespace +my name is value. # assigns `value` into the current object's `name` property + +# Please note that these names are checked at compile (read parse if in interpreted mode) time +# but you may treat them as dynamic assignments anyway + +########################################### +## 2. Lists(Arrays?) and Tuples +########################################### + +# Arrays are allowed to have multiple types +Array new < 1 ; 2 ; 'string' ; Nil. # Array new < 1 ; 2 ; 'string' ; Nil + +# Tuples act like arrays, but are immutable. +# Any shenanigans degrade them to arrays, however +[1, 2, 'string']. # [1, 2, 'string'] + +# They can interoperate with arrays +[1, 'string'] + (Array new < 'wat'). # Array new < 1 ; 'string' ; 'wat' + +# Indexing into them +[1, 2, 3] at: 1. # 2 + +# Some array operations +var arr is Array new < 1 ; 2 ; 3. + +arr head. # 1 +arr tail. # Array new < 2 ; 3. +arr init. # Array new < 1 ; 2. +arr last. # 3 +arr push: 4. # Array new < 1 ; 2 ; 3 ; 4. +arr pop. # 4 +arr pop: 1. # 2, `arr` is rebound to Array new < 1 ; 3. + +# List comprehensions +[x * 2 + y,, arr, arr + [4, 5],, x > 1]. # Array ← 7 ; 9 ; 10 ; 11 +# fresh variable names are bound as they are encountered, +# so `x` is bound to the values in `arr` +# and `y` is bound to the values in `arr + [4, 5]` +# +# The general format is: [expr,, bindings*,, predicates*] + + +#################################### +## 3. Functions +#################################### + +# A simple function that takes two variables +var add is {:a:b ^a + b.}. + +# this function will resolve all its names except the formal arguments +# in the context it is called in. + +# Using the function +add applyTo: 3 and: 5. # 8 +add applyAll: [3, 5]. # 8 + +# Also a (customizable -- more on this later) pseudo-operator allows for a shorthand +# of function calls +# By default it is REF[args] + +add[3, 5]. # 8 + +# To customize this behaviour, you may simply use a compiler pragma: +#:callShorthand () + +# And then you may use the specified operator. +# Note that the allowed 'operator' can only be made of any of these: []{}() +# And you may mix-and-match (why would anyone do that?) + +add(3, 5). # 8 + +# You may also use functions as operators in the following way: + +3 `add` 5. # 8 +# This call binds as such: add[(3), 5] +# because the default fixity is left, and the default precedance is 1 + +# You may change the precedence/fixity of this operator with a pragma +#:declare infixr 1 add + +3 `add` 5. # 8 +# now this binds as such: add[3, (5)]. + +# There is another form of functions too +# So far, the functions were resolved in a dynamic fashion +# But a lexically scoped block is also possible +var sillyAdd is {\:x:y add[x,y].}. + +# In these blocks, you are not allowed to declare new variables +# Except with the use of Object::'letEqual:in:` +# And the last expression is implicitly returned. + +# You may also use a shorthand for lambda expressions +var mul is \:x:y x * y. + +# These capture the named bindings that are not present in their +# formal parameters, and retain them. (by ref) + +########################################### +## 5. Control Flow +########################################### + +# inline conditional-expressions +var citron is 1 = 1 either: 'awesome' or: 'awful'. # citron is 'awesome' + +# multiple lines is fine too +var citron is 1 = 1 + either: 'awesome' + or: 'awful'. + +# looping +10 times: {:x + Pen writeln: x. +}. # 10. -- side effect: 10 lines in stdout, with numbers 0 through 9 in them + +# Citron properly supports tail-call recursion in lexically scoped blocks +# So use those to your heart's desire + +# mapping most data structures is as simple as `fmap:` +[1, 2, 3, 4] fmap: \:x x + 1. # [2, 3, 4, 5] + +# You can use `foldl:accumulator:` to fold a list/tuple +[1, 2, 3, 4] foldl: (\:acc:x acc * 2 + x) accumulator: 4. # 90 + +# That expression is the same as +(2 * (2 * (2 * (2 * 4 + 1) + 2) + 3) + 4) + +################################### +## 6. IO +################################### + +# IO is quite simple +# With `Pen` being used for console output +# and Program::'input' and Program::'waitForInput' being used for console input + +Pen writeln: 'Hello, ocean!' # prints 'Hello, ocean!\n' to the terminal + +Pen writeln: Program waitForInput. # reads a line and prints it back +``` |