Overview.fold

#!/usr/bin/env fold

-- ## Comments

-- This is a comment
-- TODO: Add some features.
-- XXX: Important notice.
-- FIXME: Don't forget about this issue!
-- WHAT THE HACK?

{{ Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
   tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,
   quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo
   consequat. }}


-- ## Polymorphic Variants

`Continue `foo
`Color 0xFF00FF
`Point (20.0, 0.0)


-- ## Characters

'x' 'a'
'\t' '\n'
'\99' '\9' -- Invalid char syntax


-- ## Booleans

True False


-- ## Numbers

0 1 42 100 322
0.0 3.14 0.999
0x998 0b1001


-- ## Strings

"Hello, World!"

"Hello, $name!"

"""
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,
quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo
consequat.
"""

"""
<div id="content">
  $(Post.content)
</div>
"""


-- ## Structures

mod Person
  ...
end

sig Ord
  ...
end

ext List
  ...
end

-- ## Statements

assert True
ignore (2 + 2)
undefined


-- ## Module Operations

open Control.Monad
load Opium.App

include (Printable Person)


-- ## Conditionals

if True then `OK
else `Error 102

when
  x < 0     -> -1
  x > 0     -> +1
  otherwise -> 0
end

unless (' ' in name)
  print "Enter your full name!"
end

case color
  `Red   -> "red"
  `Green -> "green"
  `Blue  -> "blue"
end


-- ## Loops

for i in [0..9]
  print "i = $i"
end

flag = ref True
while flag!
  if is_done ()
    flag := False
  end
end


-- ## Keywords

result = do
  a = 32
  b = 110
  sqrt (-4 * a * b / 2)
end

let
  a = 32
  b = 110
in
  sqrt (-4 * a * b / 2)
end

fun hello name
  print "Hello, $name!"
end


-- ## Macro

macro if $test then $true_expr else $false_expr
  ```
  case $test
    True  -> $true_expr
    False -> $false_expr
  end
  ```
end


-- ## Type

type Point =
  { x :: Float,
    y :: Float }

Int Bool Char String
List a
List (Int, { x :: Float, y :: Float }) -> Map Char Float


-- ## Delimiters

( ) { } [ ]

-- ## Operators
:: -> <- ~> $ @ |> >>

-- ## Function Definition and Application

range from: (start = 0) to: stop by: (step = 1) =
  if start == stop then []
  else start & range from: (start + 1) to: stop by: step

range from: 10 to: 100 by: 2

hello name :: String -> () =
  print "Hello, $name!"