Lab3.hs

-------------------- Brian Mock -----------------------

module Lab3 where
import List

-------------------- Problem 1  -----------------------

(==>) = flip ($)

integerToDigit (i + 1) = digits !! i

digitToInteger c = i + 1 where
    (Just i) = findIndex (== c) digits

numeralToInteger base cs = n2i base 0 cs where
    n2i base s (c:cs) = n2i base (base * s + (digitToInteger c)) cs
    n2i base s [    ] = s

integerToNumeral base 0 = ""
integerToNumeral base n =
    integerToNumeral base d
    ++ [integerToDigit m] where
        (d, m) = n `wackyDivMod` base

wackyDivMod a b
    | m == 0 && a >= b = (n - 1, b)
    | otherwise        = (n,     m)
    where (n, m) = a `divMod` b

digits = ['1' .. '9'] ++ ['a' .. 'g']

test = do
    putStrLn (joinWith sep heads)
    printSepLine
    map f xs
        ==> unlines
        ==> putStrLn where
    funcs = [show, bin, dec, hex]
    heads = words "dec ibin idec ihex" ==> map pad
    pad   = rPad 10
    sep   = " | "
    nums  = 80
    xs    = [0 .. nums]
    f x   = map ($ x) [show, bin, dec, hex]
        ==> map pad
        ==> joinWith sep

rPad width xs = get nel " " ++ xs where
    get n xs = cycle xs ==> take n
    nel = width - len
    len = length xs

printSepLine = putStrLn (cycle pattern ==> take width) where
    pattern = "-"
    width   = 60

joinWith _   [    ] = ""
joinWith _   [x   ] = x
joinWith sep (x:xs) = x ++ sep ++ joinWith sep xs

dec  = integerToNumeral 10
decI = numeralToInteger 10

hex  = integerToNumeral 16
hexI = numeralToInteger 16

bin  = integerToNumeral 2
binI = numeralToInteger 2

-------------------- Problem 2  -----------------------