http://www.perlmonks.org?node_id=785780


in reply to Re^3: qr// and user provided regex patterns...
in thread qr// and user provided regex patterns...

You say you have problems doing substitutions, but you didn't show us your attempt (despite your claim). You should have no problems using a qr// pattern in a substitution.
I think that misterMatt's problem was that he was trying to stuff a substitution into a qr//, like:
my $substitution = 's/out/in/'; my $pattern = qr/$substitution/;
which, naturally, doesn't work (well, doesn't cause a substitution, anyway).