/* dates.y
 * YACC dates example
 * illustrates union type for YYSTYPE
 *
 * to compile, use:
   lex dates.l
   yacc dates.y
   gcc -o dates y.tab.c -ly
 */

%{
#include <stdio.h>

typedef union{
  int num;
  char *str;
} YYSTYPE;

#define YYSTYPE_IS_DECLARED

char *monthtab[] =
  {   "January",      "February",       "March",        "April",
      "May",          "June",           "July",         "August",
      "September",    "October",        "November",     "December"     };
%}

%token <str> MONTH
%token <num> NUMBER

%type <str> monthnum
%type <num> day
%type <num> year

%%

line	: line date '\n'		{ printf("\n"); }
	| /* epsilon */
	| error '\n'
	;

date	: day MONTH year                { printf("%s %d, %d", $2, $1, $3); }
	| monthnum '/' day '/' year     { printf("%s %d, %d", $1, $3, $5); }
	| MONTH day ',' year            { printf("%s %d, %d", $1, $2, $4); }
	;

monthnum : NUMBER           { $$ = monthtab[$1 - 1 ] ; }
         ;

day  : NUMBER ;

year : NUMBER ;

%%

#include "lex.yy.c"