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From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.lang.perl
Subject: Re: Matching parentheses
Message-ID: <13858:Nov3016:23:4790@kramden.acf.nyu.edu>
Date: 30 Nov 90 16:23:47 GMT
References: <16600@csli.Stanford.EDU> <5209:Nov2909:58:4190@kramden.acf.nyu.edu> <12435:Nov3011:26:5990@kramden.acf.nyu.edu>
Organization: IR
Lines: 16

In article <12435:Nov3011:26:5990@kramden.acf.nyu.edu> brnstnd@kramden.acf.nyu.edu (Dan Bernstein) writes:
> #!/bin/sh
> ( echo '0'; fold -1 | sed 's,[^()],,
> s,(,1+p,
> s,),1-p,' ) | dc | ( grep -s -e - && echo 'unbalanced' || echo 'balanced' )

Whoops, thanks to William Setzer for pointing out that this doesn't
notice missing close parens.

#!/bin/sh
( echo '0'; echo '0'; fold -1 | sed 's,[^()],,
s,(,1+p,
s,),1-p,' ; echo '-p'
) | dc | ( grep -s -e - && echo 'unbalanced' || echo 'balanced' )

---Dan