# Carriage/Carriage.hs

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Quick and dirty implementation of Carriage in Haskell. Program might not explode under every condition it is supposed to explode (but please do consider every error to be an explosion, not just `BOOM`

). Runs the two examples given in the article.

explode = error "BOOM" data Elem = Int Integer | Fn ([Elem] -> [Elem]) | Sym Char instance Show Elem where show (Int i) = show i show (Fn _) = "<fn>" show (Sym c) = show c pop (e:s) = (e, s) push s e = (e:s) pick 0 ((Sym _):_) = explode pick 0 (e:_) = e pick n (_:s) = pick (n-1) s slice _ 0 _ = [] slice p k s = slice' p (reverse s) where slice' 0 s = take (fromIntegral k) s slice' n (_:s) = slice' (n-1) s ci " " = id ci "1" = \s -> push s $ Int 1 ci "$" = snd . pop ci "#" = \s -> push s $ Int $ fromIntegral $ length s ci "~" = (\s -> let (Int a, s') = pop(s) in push s' $ pick a s') ci "\\" = (\s -> let (a, s') = pop(s) (b, s'') = pop(s') in push (push s'' a) b) ci "+" = (\s -> let (Int a, s') = pop(s) (Int b, s'') = pop(s') in push s'' $ Int (a + b)) ci "-" = (\s -> let (Int a, s') = pop(s) (Int b, s'') = pop(s') in push s'' $ Int (b - a)) ci "@" = (\s -> let (Int k, s') = pop(s) (Int p, s'') = pop(s') fn = ci $ map (\(Sym c) -> c) $ slice p k s'' in push s'' (Fn fn)) ci "!" = \s -> let (Fn f, s') = pop(s) in f s' ci [] = id ci [_] = explode ci (sym:rest) = \x -> (ci rest) ((ci [sym]) x) di = reverse . map (\x -> Sym x) . filter (\x -> x /= ' ') run prog = (ci prog) (di prog)