tib.hs

import Data.Char

data Letter = Ka
            | Kha
            | Ga
            | Nga
            | Ca
            | Cha
            | Ja
            | Nya
            | Ta
            | Tha
            | Da
            | Na
            | Pa
            | Pha
            | Ba
            | Ma
            | Tsa
            | Tsha
            | Dza
            | Wa
            | Zha
            | Za
            | Achung
            | Ya
            | Ra
            | La
            | Sha
            | Sa
            | Ha
            | A
            | I
            | U
            | E
            | O
            deriving (Eq, Ord, Show, Read, Bounded, Enum)

letter :: Letter -> String
letter Achung = "'"
letter A = "a"
letter I = "i"
letter U = "u"
letter E = "e"
letter O = "o"
letter l = reverse (tail (reverse (map toLower (show l))))
letter xs = map toLower ([x | x <- (show xs), x /= 'a'])