[antlr-interest] Skipping grammar

[Anthony W Youngman]

I think you're missing the point. Define a ; as SEMI. The way I'd do it
(and this is all pseudocode) is

if_statement: "IF" lcurly (method)* rcurly "ELSE" lcurly (method)*
rcurly SEMI ;
method: blah_blah SEMI ;

That way, the lexer doesn't care whether ; is ending a method or an if
clause, and the parser won't get confused because when it hits a
right-curly it will be expecting an ELSE or a SEMI, and not a method.
And if the ELSE is optional you just mark it as such so when the parser
hits the right-curly after the if, it's expecting an ELSE or a SEMI and
nothing else.

Cheers,
Wol

-----Original Message-----
From: pwolleba [mailto:pwolleba at yahoo.no] 
Sent: 07 October 2003 08:19
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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