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Dear Monks,

If I use the construct (?(condition)yes-pattern) in a regex, and the condition is the execute-perl-code construct (?{1}), i.e. the condition is always true, the output is as expected:

my $str = 'bxAybz'; while ( $str =~ /(?(?{1})(b[xyz]))/g ) { say 'yes'; say $1; } --output:-- yes bx yes bz

But when I use the condition (?{pos() % 2 == 0}), I expect the same output, but I don't get it:

my $str = 'bxAybz'; while ( $str =~ /(?(?{pos() % 2 == 0})(b[xyz]))/g ) { say 'yes'; say $1; } --output:-- yes bx yes Use of uninitialized value $1 in say at line 9. yes bz

Three matches?

Also, I notice the x modifier doesn't work with a conditional regex:

my $str = 'bxAybz'; while ( $str =~ / (? (?{1}) (b[xyz]) ) /gx ) { say 'yes'; say $1; } --output:-- Sequence (? ...) not recognized in regex; marked by <-- HERE in m/ (? <-- HERE (?{1}) (b[xyz]) ) / at line 12.
That feels like a bug.

In reply to Conditional regex by 7stud

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