[antlr-interest] Nested Matching Parenthesis

[Matt Benson]

Not that I know anything but I think the approach you
were taking is the "ANTLR way to do it."  I think your
expr rule would be recursive, though:

> expr : PATTERN
>       | OPEN_PAREN expr CLOSE_PAREN
>       ;

But again, what do I know?

-Matt

--- cgodfrey86 <cgodfrey at epnet.com> wrote:
> Hello,
> 
> I'm trying to write a parser grammar that will check
> for matching 
> parenthesis. There can be any number of parenthesis,
> but they must 
> match
> 
> So, 
> (test) or 
> ((test)) or 
> (((test))) are all valid expressions
> 
> (test or 
> ((test 
> etc are all invalid
> 
> So, I have a rule like this
> 
> expr : PATTERN
>       | OPEN_PAREN PATTERN CLOSE_PAREN
>       ;
> 
> Would it make sense to write rules which count the
> number of 
> consecutive open parens and close parens and check
> for matches? or is 
> there an easier way to approach this that I am
> missing?
> 
> start_parens : (OPEN_PAREN)+;
> end_parens : (CLOSE_PARENS)+;
> 
> Thanks In Advance
> 
> 
>  
> 
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> http://docs.yahoo.com/info/terms/ 
> 
> 


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