Aha! Thanks, Kiss!
On Tue, Apr 5, 2016 at 1:24 PM, Adam Bergmark
The regex-compat docs say "Returns: Just https://hackage.haskell.org/packages/archive/base/4.5.0.0/doc/html/Data-Mayb... strs if the match succeeded (and strs is the list of subexpression matches), or Nothing https://hackage.haskell.org/packages/archive/base/4.5.0.0/doc/html/Data-Mayb... otherwise.”.
Adam Bergmark
On Tue 05 Apr 2016 at 22:16 Jeffrey Brown
> wrote: Esteemed Haskellers,
It is working for me, but I am puzzled by the matchRegex function:
> import Text.Regex > :i matchRegex matchRegex :: Regex -> String -> Maybe [String] -- Defined in ‘Text.Regex’
Searches that fail return Nothing:
> matchRegex (mkRegex "z") "abracadabra" Nothing
which makes sense. But why do searches that succeed return an empty list of Strings?
> matchRegex (mkRegex "a") "abracadabra" Just [] >
-- Jeffrey Benjamin Brown
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-- Jeffrey Benjamin Brown