/* lisp.l */

/* disable unused functions so we don't
   get compiler warnings about them */

%option noyywrap nounput noinput

/* change our prefix from yy to lisp */

%option prefix="lisp"

/* use the pure parser calling convention */

%option reentrant bison-bridge

%{
#include "lisp.tab.h"

#define YY_EXIT_FAILURE ((void)yyscanner, EXIT_FAILURE)

/* XOPEN for strdup */
#define _XOPEN_SOURCE 600
#include <limits.h>
#include <stdlib.h>
#include <string.h>

/* seems like a bug that I have to do this, since flex
   should know prefix=lisp and match bison's LISPSTYPE */
#define YYSTYPE LISPSTYPE

int lisperror(const char *msg);
%}

%%

[[:alpha:]][[:alnum:]]* {
	/* The memory that yytext points to gets overwritten
	   each time a pattern matches. We need to give the caller
	   a copy. Also, if strdup fails and returns NULL, it's up
	   to the caller (the parser) to detect that.

	   Notice yylval is a pointer to union now.  It's passed
	   as an arg to yylex in pure parsing mode */

	yylval->str = strdup(yytext);
	return ID;
}

[-+]?[[:digit:]]+ {
	long n = strtol(yytext, NULL, 10);

	if (n < INT_MIN || n > INT_MAX)
		lisperror("Number out of range");
	yylval->num = (int)n;
	return NUM;
}

[[:space:]]  ; /* ignore */

. { return *yytext; }