lexer.mll

{
(* 補助的な変数、関数、型などの定義 *)
open Parser
}

(* 正規表現の略記 *)
(* [...] の中は character '...' でなくてはならない *)
let space = [' ' '\t' '\n' '\r']
let digit = ['0'-'9']
let lower = ['a'-'z']
let upper = ['A'-'Z']
let alpha = lower | upper

rule token = parse
| space+  { token lexbuf }      (* スペースは読み飛ばす *)
| "(*" [^ '\n']* "\n"           (* ( * から行末まではコメント *)
          { token lexbuf }
| "+"     { PLUS }
| "-"     { MINUS }
| "*"     { TIMES }
| "="     { EQUAL }
| "<"     { LESS }
| ">"     { GREATER }
| "true"  { TRUE }
| "false" { FALSE }
| "("     { LPAREN }
| ")"     { RPAREN }
| "if"    { IF }
| "then"  { THEN }
| "else"  { ELSE }
| "let"   { LET }
| "in"    { IN }
| "fun"   { FUN }
| "->"    { ARROW }
| "rec"   { REC }
| "["     { LBRACKET }
| "]"     { RBRACKET }
| "::"    { CONS }
| "match" { MATCH }
| "with"  { WITH }
| "|"     { BAR }
| ";"     { SEMI }
| "/"     { DIV }
| "raise" { RAISE }
| "Error" { ERROR }
| "try"   { TRY }
| digit+                        (* 数字が１個以上 *)
          { NUMBER (int_of_string (Lexing.lexeme lexbuf)) }
| lower (lower | upper | digit)*
          { VAR (Lexing.lexeme lexbuf) }
| eof     { EOF }               (* 入力終了 *)
| _       { failwith ("unknown token: " ^ Lexing.lexeme lexbuf) }