What is the easiest way to get the text that matches an entire parser rule?

There are three ways:

1. The hard way: modify each parser rule so that it returns a String representing the text matched for that rule.

   decl returns [String t}
   	:	ty=type id:ID ";" {$t = ty+id.getText();}
   	;
   type returns [String t}
   	:	"int"	{$t="int";}
   	|	"float"	{$t="float";}
   	;
   

2. Build trees and then convert the tree matched for the rule to a string using either a tree walker or a simple depth-first search.

   class P extends Parser;
   options {
   	buildAST = AST;
   }
   
   decl
   	:	type id:ID ";"
   		{
   		String text = myTreeWalker(#decl);
   		System.out.println("text for decl: "+text);
   		}
   	;
   type
   	:	"int"
   	|	"float"
   	;
   

3. Override Parser.match(). You would set a flag in the parser rule you wanted to track and then make match() sensitive to it.

   class P extends Parser;
   {
       private boolean track=false;
       private StringBuffer rbuf = new StringBuffer();
       public void match(int t) throws MismatchedTokenException, TokenStreamException {
   	// must be before super.match(t), because that consumes the current token
   	if ( track ) {
               rbuf.append(LT(1).getText());
   	}
   	super.match(t);
       }
   }
   ...
   decl	:	{track=true;} type id:ID ";" {track=false;}
   	;
   type
   	:	"int"
   	|	"float"
   	;