/* C code supplied at the beginning of the file.  */

%{

#include <stdio.h>                          

#include <string.h>

extern int  yylexlinenum;                   /* these are in YYlex      */

extern char *yytext;                        /* current token           */

%}

/* Keywords and reserved words begin here.  */

%union{                                     /* this is the data union  */

    char   name[128];                       /* names                   */

}

/*-------------------- the reserved words -----------------------------*/

%token PERIOD

%token NEWLINE

%token POSITIONAL

%token VERB

%token ADVERB

%token PROPER_NOUN

%token NOUN

%token DECLARATIVE

%token CONDITIONAL

%type  <name> declarative

%type  <name> verb_phrase

%type  <name> noun_phrase

%type  <name> position_phrase

%type  <name> adverb

%type  <name> POSITIONAL VERB ADVERB PROPER_NOUN 

%type  <name> NOUN DECLARATIVE CONDITIONAL

%%

sentence_list : sentence

              | sentence_list NEWLINE sentence

              ;

sentence : verb_phrase noun_phrase position_phrase adverb period 

           {

             printf("I understand that sentence.\n");

             printf("VP = %s \n",$1);

             printf("NP = %s \n",$2);

             printf("PP = %s \n",$3);

             printf("AD = %s \n",$4);

           }

         | { yyerror("That's a strange sentence !!");  }

         ;

position_phrase : POSITIONAL  declarative PROPER_NOUN 

                  {

                    sprintf($$,"%s %s %s",$1,$2,$3);

                  }   

                | /* empty */ { strcpy($$,""); }

                ;

verb_phrase : VERB { strcpy($$,$1); strcat($$," "); }

            | adverb VERB  

              {

                sprintf($$,"%s %s",$1,$2);

              }

            ;

adverb : ADVERB      { strcpy($$,$1); }

       | /* empty */ { strcpy($$,""); }

       ;

noun_phrase : DECLARATIVE NOUN 

              {

                sprintf($$,"%s %s",$1,$2);

              }

            | CONDITIONAL declarative NOUN 

                  {

                    sprintf($$,"%s %s %s",$1,$2,$3);

                  }   

            | NOUN { strcpy($$,$1); strcat($$," "); }

            ;

declarative : DECLARATIVE { strcpy($$,$1); }

            | /* empty */ { strcpy($$,""); }

            ;

period : /* empty */

       | PERIOD

       ;

%%

/* Supplied main() and yyerror() functions.  */

int main(int argc, char *argv[])

{

  yyparse();   /* parse the file          */

  return(0);

}

int yyerror(char *message)

{

  extern FILE *yyout;

  fprintf(yyout,"\nError at line %5d. (%s) \n",

                     yylexlinenum,message);

}