[antlr-interest] converting Java code to C for PHP grammar

[Dinesha Balasuriya Weragama]

I am relatively new to ANTLR and am trying to use the PHP grammar that has been used with the ANTLR PHP target.  This grammar handles the first input token separately as 
a first body string using the following Java Code to override the nextToken() function.

@lexer::members{
    // Handle the first token, which will always be a BodyString.
    public Token nextToken(){
        //The following code was pulled out from super.nextToken()
        if (input.index() == 0) {
            try {
                state.token = null;
                state.channel = Token.DEFAULT_CHANNEL;
                state.tokenStartCharIndex = input.index();
                state.tokenStartCharPositionInLine = input.getCharPositionInLine();
                state.tokenStartLine = input.getLine();
                state.text = null;
                mFirstBodyString();
                state.type = BodyString;
                emit();
                return state.token;
            } catch (NoViableAltException nva) {
                reportError(nva);
                recover(nva); // throw out current char and try again
            } catch (RecognitionException re) {
                reportError(re);
                // match() routine has already called recover()
            }    
        }
        return super.nextToken();
    }
}

mFirstBodyString is created to identify the first body string as the following fragment in the grammar.

fragment
FirstBodyString
    : (('<' ~ '?')=> '<' | ~'<' )* '<?' ('php'?)
    ;

I am attempting to convert this to C but end up with a runtime error with a pointer to memory location 0x0.  My attempted code (ignoring the error handling for now) is 
given below.

@lexer::apifuncs{
  TOKENSOURCE(ctx)->nextToken=myNextToken;
}

@lexer::members{

#include "phpTest.h"
     pANTLR3_COMMON_TOKEN myNextToken(pANTLR3_TOKEN_SOURCE toksource){
     
        pANTLR3_LEXER lexer;
        
        lexer=(pANTLR3_LEXER)(toksource->super);
        if(lexer->input->istream->index(lexer->input->istream)==0){
              lexer->rec->state->token=NULL;
              lexer->rec->state->channel=ANTLR3_TOKEN_DEFAULT_CHANNEL;
              lexer->rec->state->tokenStartCharIndex=lexer->input->istream->index(lexer->input->istream);
              lexer->rec->state->tokenStartCharPositionInLine=lexer->input->getCharPositionInLine(lexer->input);
              lexer->rec->state->tokenStartLine=lexer->input->getLine(lexer->input);
              lexer->rec->state->text=NULL;
              mFirstBodyString(lex);
              lexer->rec->state->type=BodyString;
              lexer->emit(lexer);
              return lexer->rec->state->token;
        }
        return lexer->rec->state->token;
     }
}

phpTest.h just contains a global declaration of lex which is of type pphpLexer and is the lexer used in the test rig.  Please let me know what I'm doing wrong.