/* 

 *   Copyright (c) 2000, 2006 Michael J. Roberts

 *   

 *   This file is part of TADS 3.

 *   

 *   The header defines the GrammarProd intrinsic class and some associated

 *   properties and constants.  

 */

#ifndef _GRAMPROD_H_

#define _GRAMPROD_H_

/* include our base class definition */

#include "systype.h"

/*

 *   The GrammarProd intrinsic class is a specialized type that's used to

 *   create parsers.  An object of this type is created automatically by the

 *   TADS 3 compiler for each 'grammar' statement.  This class encapsulates

 *   the prototype token list and mapping information defined in a 'grammar'

 *   statement, and provides a method to match its prototype to an actual

 *   input token string.  

 */

intrinsic class GrammarProd 'grammar-production/030001': Object

{

    /*

     *   Parse the token list, starting at this production, using the given

     *   dictionary to look up tokens.  Returns a list of match objects.  If

     *   there are no matches to the grammar, simply returns an empty list.  

     */

    parseTokens(tokenList, dict);

    /*

     *   Retrieve a detailed description of the production.  This returns a

     *   list of GrammarAltInfo objects that describe the rule alternatives

     *   that make up this production.  

     */

    getGrammarInfo();

}

/*

 *   Token slot types.  Each token slot in an alternative has a type, which

 *   determines what it matches in an input token list.  getGrammarInfo()

 *   returns these type codes in the GrammarAltTokInfo objects.  

 */

#define GramTokTypeProd    1              /* token matches a sub-production */

#define GramTokTypeSpeech  2     /* token matches a specific part of speech */

#define GramTokTypeLiteral 3              /* token matches a literal string */

#define GramTokTypeTokEnum 4            /* token matches a token class enum */

#define GramTokTypeStar    5    /* token matches all remaining input tokens */

#define GramTokTypeNSpeech 6      /* matches any of several parts of speech */

/* 

 *   Properties for the first and last token indices, and the complete

 *   original token list.

 *   

 *   Each match tree object will have the firstTokenIndex and lastTokenIndex

 *   properties set to the bounding token indices for its subtree.  Each

 *   match tree object will also have tokenList set to the original token

 *   list passed to the parseTokens() that created the match tree, and

 *   tokenMatchList set to a list of the Dictionary's comparator's

 *   matchValues() result for each token match.  

 */

property firstTokenIndex, lastTokenIndex, tokenList, tokenMatchList;

export firstTokenIndex 'GrammarProd.firstTokenIndex';

export lastTokenIndex  'GrammarProd.lastTokenIndex';

export tokenList       'GrammarProd.tokenList';

export tokenMatchList  'GrammarProd.tokenMatchList';