[antlr-interest] Multiple lexers (c++ code gen.)

[Arnar Birgisson]

You have to associate each lexer in the selector with a identifying
string, and then use that string as an argument to selctor->push.

Here's how I do it:

 istream& input = cin;

 TokenStreamSelector selector;

 LexerA aLexer(input);
 aLexer.initialize(&selector);

 LexerB bLexer(forritLexer.getInputState());
 bLexer.initialize(&selector);

 selector.addInputStream(&aLexer, "LexerA");
 selector.addInputStream(&bLexer, "LexerB");
 selector.select("LexerA");

 ASTFactory my_factory;
 MyParser parser(selector);

 parser.initializeASTFactory(my_factory);
 parser.setASTFactory(&my_factory);

 parser.start();

and then use it like this in LexerA:

 UNIT_LBRACE
   : '{' { selector->push("eininglexer"); }
   ;

Hope this helps.

Arnar

> -----Original Message-----
> From: marcschellens [mailto:m_schellens at hotmail.com] 
> Sent: 20. nóvember 2003 15:08
> To: antlr-interest at yahoogroups.com
> Subject: [antlr-interest] Multiple lexers (c++ code gen.)
> 
> 
> Somehow the switch between two lexers seems not to work:
> 
> setup is like this:
> 
>     TokenStreamSelector selector;
>     
>     FMTLexer   lexer( istr);
>     lexer.SetSelector( selector);
>     
>     CFMTLexer  cLexer( lexer.getInputState());
>     cLexer.SetSelector( selector);
> 
>     lexer.SetCLexer( cLexer);
> 
>     selector.select( &lexer);
> 
>     FMTParser  parser( selector);
> 
>     parser.initializeASTFactory( FMTNodeFactory);
>     parser.setASTFactory( &FMTNodeFactory );
>    
>     parser.format( 1);
> 
> And usage:
> 
> in FMTLexer (switch to CFMTLexer):
> 
> CSTRING!
> 	: 'c' '\"' { cLexer->DoubleQuotes( true); 
> selector->push(cLexer);}
>     | 'c' '\'' { cLexer->DoubleQuotes( false); 
> selector->push( cLexer);}
> 	;	
> 
> cLexer is CFMTLexer* (private member in lexer).
> 
> Do I make an obvious mistake?
> thanks,
> marc
> 
> in CFMTLexer (switch back)
> 
> protected
> ENDSTR1
>     : ('\"') => '\"' 
>     | { selector->pop();}
>     ;
> 
> 
> 
> 
> 
> 
>  
> 
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