Re^2: Regular Expression Constructs ?<= and ?=

First, do you realize (??{ print $^N }) is causing the regexp to try to match "1", the return value of print? You should probably use something that's guaranteed not to match like (??{ print("$^N\n"); '(?!)' })or something that's guaranteed to match like (??{ print("$^N\n"); '(?=)' })

Or if you are only using the contents of the code block for it's side effects, use (?{ ... }) which always succeeds and otherwise has no effect upon the matching process. From perlre

This zero-width assertion evaluates any embedded Perl code. It always succeeds, and its code is not interpolated.

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Re^3: Regular Expression Constructs ?<= and ?= by diotalevi (Canon) on Jan 12, 2006 at 04:11 UTC
Or if you do want your code's evaluation to affect the regex's match, use the conditional expression (?(...)...\|...). `(?(?{ YOUR CODE HERE }) TRUE \| FALSE )` ⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊	[reply] [d/l]