Continuation based lexer (partial)

gistfile1.fs

type LispLex = Bra | Ket | Dot | Str of string | Num of int | Symbol of string
let alpha c = ((c >= 'a') && (c <= 'z')) || ((c >= 'A') && (c <= 'Z'))
let digit c = (c >= '0') && (c <= '9')
let eqChar c c' = c = c'
let l2s l = String(List.toArray l)
let ( ^| ) p q = fun x -> (p x) || (q x)

// Read a symbol from the input
let readSymbol s char g =
     (lexGetChar s, alpha ^| digit ^| eqChar '_') ^*
     (fun l ->
             fun opt ->
                    lexPutLexeme s (Symbol (l2s ([char]@l))) (g opt));;