%{
/* need this for the call to atof() below */
#include <math.h>
/* need this for printf(), fopen() and stdio below */
#include <stdio.h>
%}

DIGIT 	[0-9]
ID	[a-z][a-z0-9]*

%%

{DIGIT}+		{
			printf("An integer:%s(%d)\n",yytext,atoi(yytext));
			}

{DIGIT}+"."{DIGIT}*	{
			printf("A float: %s (%g)\n",yytext,atof(yytext));
			}
if|then|begin|end|procedure|function	{
			printf("A keyword: %s\n",yytext);
			}

{ID}			{printf("An identifier %s\n",yytext);}

"+"|"-"|"*"|"/"		{printf("An operator %s\n",yytext);}

"{"[^}\n]*"}"           {/* eat up one-line comments */}

[ \t\n]+                {/* eat up white space */}

.                        {printf("Unrecognized character: %s\n", yytext);}

%%
int main(int argc, char *argv[]){
	++argv, --argc;
	if (argc>0)
		yyin =  fopen(argv[0],"r");
	else
		yyin = stdin;
	yylex();
}

yywrap(){}