Hello.hscript

-- file Hello.hscript
"Hello world"

let val = id
let assert = id
let a = 3

val a

let square x = x * x

val $ square 3
square 5


"lets make an assertion: square (-1) == square 1"
assert $ square (-1) == square 1

"no lets just quickcheck it for arbirary n, square (-n) == square n"
import Test.QuickCheck
quickCheck $ \n -> square (-n) == square n


:{ 
let fib 0 = 0
    fib 1 = 1
    fib n = fib (n-1) + fib (n-2)  
:}

"lets do some arbitrary IO!"
hscript <- readFile "Hello.hscript"

"Does this file start with \"Hello world\"?"
assert $ take 13 hscript == "\"Hello world\""

"lets mutate some variables!!"
import Data.IORef
let (?) = readIORef
let (++)  = flip modifyIORef (+1)


"lets let x be 1"
x <- newIORef (1 :: Integer)
"whats x?"
(x?)
"let's increment x again"
(x++)
"what's x?"
(x?)
"let's increment x again"
(x++)
"what's x?"
(x?)
"let's increment x again"
(x++)
"what's x?"
(x?)

"wait, fib 13, what was that?"
fib 13

"let's increment x again"
(x++)
(x?)

data Hi = Hi | Ho deriving (Eq,Ord,Show)
:{
let hi Ho = Hi
    hi Hi = Ho
:}
assert $ Hi == hi Ho
Hi


import System.Directory
import Control.Monad ((>=>))

d <- getDirectoryContents "." >>= mapM getPermissions
let e = filter executable d

mapM_ print e