As impressive as this is (and I haven't got it entirely figured out yet) there are a couple bugs. $first contain extra spaces when the group includes words that start with different letters... localize $" or just do a boring join to fix that. Also, words with multiple occurances of the first letter ('aabc' instead of 'abc') get excluded even when they shouldn't.

The following output shows several incorrect cases using an exclude list of qw(dog cat pig): 

(?-xism:^[^p c d]*(?:(?:p(?!ig)|c(?!at)|d(?!og))[^p c d]*)*$)
dog => 
cat => 
pig => 
owl => 1
ddog => 
ccat => 
ppig => 
pdog => 
pcat => 
 elephant =>
ppppcatgggg =>

[download]

-Blake

In reply to Re: Word Exclusion Regex (was Re: regex problem) by blakem
in thread regex problem by Anonymous Monk

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