in reply to die in regexp

i don't know, but you could avoid the issue w/something like (esp since you're not modifying the string, so no point in a substitution): 
my $s = "qwe";
croak "w is bad" if $s =~ /w/;   # croak if the string contains a w
# OR, faster:
croak "w is bad" if index($s,'w') >= 0;

[download]
(don't use $a or $b as a varname -- it's a global var for sort)

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Re^2: die in regexp
by powerman (Friar) on Jul 03, 2006 at 19:25 UTC
    I know how I can avoid this issue. :-) I don't know is I should avoid it. :) Also, I can't avoid it so ease - I need to do s/// in some complex template, and I wish to detect errors in this template. Example with "qwe" can be converted to simple m//, but not my real task. My real task can be converted to something like: 
    while (1) {
    $tmpl =~ /\G(...)/gcs  && do {
       if ($1 eq "w") {
           croak "w is bad";
       } else {
           $result .= process_template($1);
       }
    }
 || $tmpl =~ /\G(...)/gcs  && do {
       ...do.something.else...
    }
 || last;
}

    [download]
    You see, it's too complex to replace current single-line s/// just to be able to croak() on errors. :(
[reply]
[d/l]
      My real task can be converted to something like

      ...this?

      use Tie::IxHash;
tie my %dt, 'Tie::IxHash',
  qr/one/ => \&handle_one,
  qr/two/ => \&handle_two;
my $c="trigger one trigger two";

sub handle_one {
  print "one: ", shift, "\n";
}
sub handle_two {
  print "two: ", shift, "\n";
}

foreach (keys %dt) {
  $c =~ /\G.+?($_)/gcs and $dt{$_}->($1);
}

      [download]

      --
      David Serrano

[reply]
[d/l]
        Nice example, :) but no, my task can't be converted to something like this. Here is complete story. I've template like: "some text @~var1~@ some other text @~var 2~@ end of text" and I've this hash: { "var1" => $value1, "var 2" => $value2, }. So: 
        $tmpl =~ s/@~(.*?)~@/$hash{$1}/g;

        [download]
        But I wish to add some protection here. Minimum: 
        $tmpl =~ s/@~(.*?)~@/
    defined $hash{$1} ? $hash{$1}
  :                     croak("@~$1~@ not defined")
  /ge;

        [download]
        Maximum - also detect orphaned @~ and ~@ like in this example: "some ~@ text @~ here @~".
[reply]
[d/l]
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