in reply to Regex variables with delimiters

... the =~ operator has been cunningly designed so that ... there is a builtin assumption that it uses '/' delimiters ...

A counterexample: 

c:\@Work\Perl\monks>perl -wMstrict -le
"my $raw = '/this/stuff/';
 print 'raw: yes' if 'does/this/stuff/match?' =~ $raw;
 ;;
 my $regex = qr/$raw/;
 print 'regex: yes' if 'and/this/stuff/also?' =~ $regex;
"
raw: yes
regex: yes

[download]

Give a man a fish:  <%-{-{-{-<

Replies are listed 'Best First'.
Re^2: Regex variables with delimiters
by clerew (Novice) on May 19, 2019 at 15:11 UTC

    Yes that works, but my copy pf the O'Reilly Camel book seems to suggest otherwise :-(.

    Anway, after a Good Night's sleep I worked out how I should have done it:

    $regexp = <STDIN>

    probably with a chomp somewhere, and then

    $line =~ m?$regexp?

    That seems to work fine, so thanks to all who replied.

    Additional remark on May 20th

    actually, that didn't work. Due to the special peculiarities of m?xxxxx? matches, you need to call reset whenever you change $regexp. Much simpler just to use a different delimiter, so here is my final versions, now working as intended:

    $line =~ m#$regexp#
[reply]
[d/l]
[select]
      ...  $line =~ m?$regexp? ... That seems to work fine ...

      Again,  m?...? is a special case of the  m// operator (per this), but if you're happy with its one-match-only behavior, I'm happy too! :)

      Give a man a fish:  <%-{-{-{-<

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom