in reply to Re: Precompiling substitution regex
in thread Precompiling substitution regex

['(robert|bobby)', 'bob']

Your example regex has a capture group, but the subsequent substitution doesn't seem to offer any opportunity to use what was captured. Is there any reason for capturing?

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Re^3: Precompiling substitution regex
by Anonymous Monk on Jul 02, 2014 at 13:48 UTC
    No, that's a typo. Interesting - is there a way to pass captured groups to be substituted instead of straight strings?
[reply]

      Okay my stab at using captured groups as well is to use eval in the replacement evaluation, i.e.,

      foreach (@SUB_REC) {
  $yourText =~ s/$_->[0]/eval qq{"$_->[1]")/eg;
}

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      The above allows me to pass replacement strings and capture groups, e.g., 

      my @SUB_REC = map {[qr{$_->[0]}, $_->[1]]} (
  ['robert|bobby', 'bob'],
  ['(abc)(1234)(def)', '$1$3'] 
);

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        Using a doubled  /e regex modifier is also possible and, IMHO, better because it is simpler. (The  /e modifier can be repeated any number of times for additional 'levels' of expression evaluation.) 

        c:\@Work\Perl>perl -wMstrict -le
"my @SUB_REC =
   map [ qr{$_->[0]}, $_->[1] ],
   ( [ '\b(robert|bobby)\b', 'bob (not $1)' ], )
   ;
 ;;
 my $yourText = 'robert dobbs and roberto jones and bobby hope';
 print qq{'$yourText'};
 ;;
 $yourText =~ s{ $_->[0] }{ qq{qq{$_->[1]}} }xmsgee for @SUB_REC;
 print qq{'$yourText'};
"
'robert dobbs and roberto jones and bobby hope'
'bob (not robert) dobbs and roberto jones and bob (not bobby) hope'

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