structure Tokens = Tokens
open Tokens

type pos = unit
type svalue = svalue
type ('a, 'b) token = ('a, 'b) token
type lexresult = (svalue, pos) token

fun eof () = SEMICOLON((),())
fun error (e, pos, _) = (print e; print "\n")



%%

%header (functor MyCLexFun(structure Tokens : MyC_TOKENS));

space=[\ \t\n\r];
digit=[0-9];
alpha=[A-Za-z_];



%%

"="           => (EQUAL((),()));
"+"           => (PLUS((),()));
"("           => (LPAREN((),()));
")"           => (RPAREN((),()));
">"           => (GREATER((),()));
"{"           => (LBRACE((),()));
"}"           => (RBRACE((),()));
";"           => (SEMICOLON((),()));
"-"? {digit}+ => (CONST(valOf(Int.fromString yytext),(),()));
{alpha}+      => (case yytext of
		      "while" => WHILE((),())
		    | "print" => PRINT((),())
		    | x => VAR(x,(),()));
{space}+      => (lex()(* 空白をスキップして字句解析を続行 *));