in reply to Re^2: Regexp substitution using variables
in thread Regexp substitution using variables

This is interesting. Can you provide some additional examples, including more esoteric ones, and possible a little sample text? I was just wanting to look at the challenges you're facing more pragmatically. Test cases would be fantastic.


Dave

  • Comment on Re^3: Regexp substitution using variables

Replies are listed 'Best First'.
Re^4: Regexp substitution using variables
by MikeTaylor (Sexton) on Nov 25, 2020 at 23:23 UTC
    I'm afraid I'm not yet far enough into the project to have solid examples, let alone test cases. I am waiting on the customer to let me know what specific transformations they need. But it would not be unlikely that we'd find, for example, a field containing call-numbers like PR.123.ABC that we needed to change to PR-ABC:123, which of course we could do with s/(.*)\.(.*)\.(.*)/$1-$3:$2/.
[reply]

      Win8 Strawberry 5.8.9.5 (32)  Thu 11/26/2020  5:05:35
C:\@Work\Perl\monks
>perl
use strict;
use warnings;

my $pattern     = '(.*)\.(.*)\.(.*)';
my $replacement = '$1-$3:$2';
my $flags       = '';

# $got_g is true if /g modifier present in flags.
# ($flags, my $got_g) = sanitize_flags_detect_g($flags);

fixup_forward_slashes($pattern, $replacement);

my $value = 'PR.123.ABC';

print "replacement '$replacement' \n";

my $eval_string = "\$value =~ s/$pattern/$replacement/$flags";
print "eval_string '$eval_string' \n";

eval $eval_string;
print "eval err '$@' \n";
print "output '$value' \n";

sub fixup_forward_slashes { s{/}'\/'g for @_; }
^Z
replacement '$1-$3:$2'
eval_string '$value =~ s/(.*)\.(.*)\.(.*)/$1-$3:$2/'
eval err ''
output 'PR-ABC:123'

      [download]

      Give a man a fish:  <%-{-{-{-<

[reply]
[d/l]
[select]
        And, as LanX showed in Re^3: Regexp substitution using variables, you can now try 
        $replacement = '@{[`ls`]};  # use dir on MSWin

        [download]
        or even rm -rf / or deltree or whatever the equivalent is. This is too strong.

        map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]
[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom