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(The following is perhaps a bit OT to the main thread, or else already touched upon in an update. Oh, well...) ... I think that adding an extra (?:...) makes the generated regex look a little more complex than it needs to be ... those are just stylistic concerns ... Please see Re: Recognizing 3 and 4 digit number and thereunder for a long discussion between myself and kcott on these "stylistic concerns." Personally, I still don't see the need for the extra explicit (?:...) wrap step. The implicit wrap becomes explicit quick enough if you print the stringized Regexp object, and this feature of a Regexp object should be deeply understood from the moment one begins to use them. ... skip the intermediate string variable, like in Haarg's post here: my ($regex) = map {qr/$_/} join '|', map .... ... it's more robust ... To continue the previous point, I feel it's important to get a regex into a Regexp form as quickly as possible: no dilly-dallying. Once objectified, it can be used atomically when composing more complex regex expressions: (Of course, this compositional capability is also addressed by the (DEFINE) predicate of the (?(condition)yes-pattern) conditional expression of Perl 5.10+.) The only situation which I'm aware of in which this compositional atomicity breaks down is for something like where $rx{$n} $rx{$n,} $rx{$n,$m} are all taken as hash element accesses. This can be fixed simply by an explicit layer of non-capturing group wrapping (entirely necessary here!): (?:$rx){$n} (?:$rx){$n,} (?:$rx){$n,$m} Give a man a fish: <%-{-{-{-< In reply to Re^3: [RFC] [OT] Building Regex Alternations Dynamically (updated)
by AnomalousMonk
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