/*=====<< Scanner for BASIC >>=====*/

%{

#include "mbasic.h"
#include "y.tab.h"

%}

%s BEXPR 
NLIT		(([0-9]+)|([0-9]*\.[0-9]+))
SLIT		\"[^"\n]*["\n]
IDENT		[a-z][a-z0-9]*

%%

{NLIT}		{
			yylval.number = atof(yytext);
			return(NUMLIT);
		}
{SLIT}		{
			if(yytext[yyleng-1] == '\n') unput('\n'); 
			yylval.string = (char *)malloc(yyleng-1);
			strcpy(yylval.string,&yytext[1]); 
			yylval.string[strlen(yylval.string)-1] = 0;
			return STRLIT;
		}
cls		return CLS;
dim		return DIM;
as		return AS;
number		return NUMBER;
string		return STRING;
boolean		return BOOLEAN;
input		return INPUT;
print		return(PRINT);
;		return ';';
if		{
			BEGIN BEXPR;
			return(IF);
		}
<BEXPR>=	return(EQ); 
>=		return(GE);
\<=		return(LE);
\<>		return(NE);
\<		return(LT);
>		return(GT);
and		return(AND);	
or		return(OR);
not		return(NOT);
true		{
			yylval.boolean = 1;
			return(BOOLIT);
		}
false		{
			yylval.boolean = 0;
			return(BOOLIT);
		}
then		{
			BEGIN 0;
			return(THEN);
		}
else		printf("ELSE ");
end[ \t]+if	printf("ENDIF ");
=		return '='; 
:		printf("LABEL ");
goto		printf("GOTO ");
gosub		printf("GOSUB ");
return		printf("RETURN ");
{IDENT}		{
			yylval.boolean = VarKey(yytext);
			if(!yylval.boolean)
			{
				yylval.string = (char *)malloc(strlen(yytext)+1);
				strcpy(yylval.string,yytext);
				return UNREC;
			}
			else
			{
				switch(TypeOf(yylval.boolean))
				{
					case TP_STRING:
						return SVAR;
						break;
					case TP_NUMBER:
						return NVAR;
						break;
					case TP_BOOLEAN:
						return BVAR;
						break;
				}
			}
		}
"+"		return '+';
"-"		return '-';
"*"		return '*';
"/"		return '/';
"^"		return '^';
"("		return '(';
")"		return ')';
(rem.*\n)|('.*\n)	unput('\n');	
\n		return EOL; 
[ \t]+		/* eat up whitespace */
.		printf("Syntax Error: \"%s\"\n", yytext);

%%

main(int argc, char **argv)
{
	if(argc > 1) 
	{
		yyin = fopen(argv[argc-1],"r");
		if(yyin == NULL) 
		{
			printf("Error trying to read \"%s\".\n",argv[argc-1]);
			return;
		}
	}
	else yyin = stdin;
	yyparse();
	close(yyin);
}

/*=====<< Indicate Source Code is Finished >>=====*/
int yywrap()
{
	return 1;
}