> to expect that Perl might recognize /$foo/ or /foo/g as being able to re-use a compiled expression instead of compiling a new one.

the first case maybe, tho I'm not sure about the implications of having no modifiers outside but inside.

But how did you prove that /$foo/ is recompiling?

Anyway as I said $str =~ $foo shouldn't! (untested)

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

In reply to Re^4: On the regex pattern variable to be inserted into another by LanX
in thread On the regex pattern variable to be inserted into another by Anonymous Monk

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