type token = Kwd of string | Ident of string | Int of int | Float of float | String of string | Char of char
val make_lexer: string list -> (char Stream.t -> token Stream.t)
let lexer = make_lexer ["+";"-";"*";"/";"let";"="; "("; ")"]
The associated parser would be a function from token stream to, for instance, int, and would have rules such as:
let parse_expr = parser [< 'Int n >] -> n | [< 'Kwd "("; n = parse_expr; 'Kwd ")" >] -> n | [< n1 = parse_expr; n2 = parse_remainder n1 >] -> n2 and parse_remainder n1 = parser [< 'Kwd "+"; n2 = parse_expr >] -> n1+n2 | ...