Q for regexp experts

Ludwig Callewaert ludwig_callewaert at frontierd.com
Fri Dec 8 16:24:45 CET 2000


Harald Kirsch wrote:
> 
> Even with perl-compatible regular expressions it seems to be
> impossible to specify a pattern which matches
> 
>    `the longest substring not containing separator' SEP
> 
> Put another way, from a given starting point, the pattern shall match
> everything until just before the next occurence of SEP. A first
> attempt is something like
> 
>    [^SEP]*
> 
> but this disallows S', 'E' and 'P' in between the separators.
> 
> I tried something like (.(?!SEP))+ but it somehow does not work. Is it
> at all possible to get this to work with regular expressions?
> 
>   Harald Kirsch
> 
> --
> ----------------+------------------------------------------------------
> Harald Kirsch   | kirschh at lionbioscience.com | "How old is the epsilon?"
> LION Bioscience | +49 6221 4038 172          |        -- Paul Erdös

What about:

set s "the longest matching String not containing SEP"

regexp -- ".*(?=SEP)" $s match

puts $match

> the longest matching String not containing 

Ludwig

-- 

Ludwig Callewaert       e-mail: ludwig_callewaert at frontierd.com
Senior Software Engineer        Frontier Design, Belgium
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