[antlr-interest] Re: Nested Matching Parenthesis

[cgodfrey86]

Thanks for the 2nd set of eyes. I had it like that at one point and 
changed it.

--- In antlr-interest at yahoogroups.com, Matt Benson <gudnabrsam at y...> 
wrote:
> 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 e...> 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
> > 
> > 
> >  
> > 
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/ 
> > 
> > 
> 
> 
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