DataChar.fr

module learnyou.chapter07.DataChar where

import frege.Prelude hiding ( isNumber )
import frege.data.List
import frege.data.Char

encode :: Int -> String -> String
encode shift msg =
    let ords = map ord $ unpacked msg
        shifted = map (+ shift) ords
    in  packed $ map chr shifted

decode :: Int -> String -> String
decode shift msg = encode (negate shift) msg

main _ = do

    println $ all isAlphaNum "bobby283".toList
    println $ all isAlphaNum "eddy the fish!".toList

    println $ words "hey guys its me"
    println $ filter (not . any isSpace) . groupBy ((==) `on` isSpace) $
        "hey guys its me".toList

    println $ generalCategory ' '
    println $ generalCategory 'A'
    println $ generalCategory 'a'
    println $ generalCategory '.'
    println $ generalCategory '9'
    println $ map generalCategory " \t\nA9?|".toList

    println $ map digitToInt "34538".toList
    println $ map digitToInt "FF85AB".toList

    println $ intToDigit 15
    println $ intToDigit 5

    println $ ord 'a'
    println $ chr 97
    println $ map ord "abcdefgh".toList

    println $ encode 3 "Heeeeey"
    println $ encode 4 "Heeeeey"
    println $ encode 1 "abcd"
    println $ encode 5 "Marry Christmas! Ho ho ho!"

    println $ encode 3 "Im a little teapot"
    println $ decode 3 "Lp#d#olwwoh#whdsrw"
    println $ decode 5 . encode 5 $ "This is a sentence"