[antlr-interest] Skipping grammar

[Arnar Birgisson]

I haven't tried this, but you could have this in your lexer:

class MyLexer extends Lexer

tokens {
  INNER_LCURLY, INNER_RCURLY;
}

{
  private int nestingLevel = 0;
}

LCURLY
  : '{' { if (++i > 0) $setType(INNER_LCURLY); }
  ;

RCURLY
  : '}' { if (i > 0) { i--; $setType(INNER_RCURLY); }
  ;

which gives the parser seperate tokens for inner and outer curly-braces.
This allows you to do this in the Parser

method
  : "method" mName LCURLY ( ~RCURLY )* RCURLY
  ;

Arnar

> -----Original Message-----
> From: pwolleba [mailto:pwolleba at yahoo.no] 
> Sent: 7. október 2003 07:19
> To: antlr-interest at yahoogroups.com
> Subject: [antlr-interest] Skipping grammar
> 
> 
> I am pretty new to ANTLR so maybe this question is very trivial, if 
> so even better then maybe it is a simple solution to my problem. 
> Anyway I am struggling with writing a new parser in ANTLR to replace 
> and old implementation in Flex/Bison, this to make a product that are 
> open for implementation from both C++ as well as Java. 
> 
> The parser will parse a language that we are using to build 
> databases, and it must support this language 100% if to be accepted. 
> 
> Here is the code cutting that I am struggling with.
> 
> method name{
>   SomeText!()text[];
>   if(a < b && b < c){
>      SomeText()!()[];
>   }
>   else{
>      SomeText()!()[];
>   };
> };
> 
> I am not interesting in the expression that is inside the name 
> method, I just want ANTLR to grab the text for me, and put it as a 
> node inside the tree. The problem is the fact that the if/else 
> statement is ending with a "};" which is the same token as the method 
> end token, and I have no guarantee that there could be more that one 
> inside the method. A solution would be to make a counter that will 
> increase for each "{" and decrease for each "}", then I would know 
> when the method ends. To my frustration I don't know how I should 
> make such a counter in ANTRL, that still supports implement in both 
> Java or C++ code.
> I would be really really happy if someone could help me with this 
> problem!
> 
> Best reagards,
> 
> Per
> 
> 
> 
>  
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