Re: [FWP] sexeger

[Ronald J Kimball <rjk@linguist.dartmouth.edu>]

On Fri, Sep 15, 2000 at 02:20:00AM -0400, Jeff Pinyan wrote:

> In this simple example, we're matching the LAST occurrence of 'aaaa' in a
> string.  In the standard approach, we'd use something like:
> 
>   /aaaa(?!.*aaaa)/

'aaaaaaaa' =~ /aaaa(?!.*aaaa)/
  ^^^^

The substring that is matched is substr('aaaaaaa', 1, 4), not
substr('aaaaaaa', 4, 4), because (?!.*aaaa) allows for a substring of three
'a's.  So, if the string ends with more than four 'a's, this regex does not
give the desired results.


> This could be optimized to
> 
>   /aaaa(?:[^a]+a{1,3})*$/

That one does give the desired results.


Ronald

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