%{
/*
 * This lexer accepts input from another file instead of stdin
 * This is accomplished reassigning yyin = file
 */

%}
%%

[\t ]+	/*recognize and ignore any number of tabs or white spaces*/ ;

[a-zA-Z ] {
	printf("%s:	This is a letter\n", yytext);
	}

.|\n	{ ECHO; /* normal default anyway */ }

%%

main(argc,argv)
int argc;
char **argv;
{
        if (argc > 1) {
                FILE *file;

                file = fopen(argv[1], "r");
                if (!file) {
                        fprintf(stderr,"could not open %s\n",argv[1]);
                        exit(1);
                }
                yyin = file;
        }
        yylex();
        return 0;
}