ch1-06.y

%{
#include <stdio.h>
#include "ch1-06.h"
/* we found the following required for some yacc implementations. */
/* #define YYSTYPE int */
%}

%token NOUN PRONOUN VERB ADVERB ADJECTIVE PREPOSITION CONJUNCTION

%%

sentence: simple_sentence   { printf("Parsed a simple sentence.\n"); }
  | compound_sentence { printf("Parsed a compound sentence.\n"); }
  ; 

simple_sentence: subject verb object
  |  subject verb object prep_phrase
  ;

compound_sentence: simple_sentence CONJUNCTION simple_sentence
  |  compound_sentence CONJUNCTION simple_sentence
  ;

subject:  NOUN
  |  PRONOUN
  |  ADJECTIVE subject
  ;

verb:    VERB
  |  ADVERB VERB
  |  verb VERB
  ;
  
object:    NOUN
  |  ADJECTIVE object
  ;

prep_phrase:  PREPOSITION NOUN
  ;

%%

int main()
{
  yyparse();
  return 0;
}

int yyerror(char *s)
{
  fprintf(stderr, "%s\n", s);
  return 0;
}