/* This file defines a parser for the propositional calculus */

import java_cup.runtime.*;
import truthtable.*;    // truth table abstract syntax and semantic classes

action code {: /* things you want to use in the bottom portion goes here */ :}

parser code {: 
/* these variables must be declared here: */
String intext;    // concrete syntax typed in by user
Yylex scanner;    // scanner object
:};

init with {:
try {			/* Get Input, form lexer: */
  java.io.InputStreamReader lr = 
     new java.io.InputStreamReader(System.in);
  java.io.BufferedReader lineinput = 
     new java.io.BufferedReader(lr);
/* didn't figure out how to pass in input from the main program: */
  System.out.print("Enter Propositional Sentence: ");
  intext = lineinput.readLine();
} catch (Exception ee) {}
/* scanner needs an input stream */
scanner = new Yylex(new java.io.StringBufferInputStream(intext)); 

:};

scan with {: return scanner.next_token(); :};

/* grammer symbols: */
/* types are defined in truthtable.java */
/* (abstract) type 'proposition' is type of syntax tree node */
/* "0" is false, "1" is true. */


terminal String 	LETTER;
/* String is the real type of the "Object" stored in the "value" field of
   a LETTER "Symbol". */

/* define reset of grammar symbols here... */

/* don't forget the precedence relations here... */




/* the grammer and actions to build abstract syntax tree goes here: */

/* remember that in an "CONST:e1", e1 is the "Object" associated
   with symbol CONST, which is in fact a "String".  This argument is 
   stored in the "value" field of the "Symbol" class. */

EXP     ::= CONST:s1 	{: RESULT = new constantProp(s1); :}


....