Re^2: die in regexp

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. :(

Comment on Re^2: die in regexp Download Code

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Re^3: die in regexp by Hue-Bond (Priest) on Jul 03, 2006 at 20:05 UTC
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]
Re^4: die in regexp by powerman (Friar) on Jul 03, 2006 at 20:39 UTC
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] [select]
Re^5: die in regexp by graff (Chancellor) on Jul 03, 2006 at 21:51 UTC
Here is complete story. Thanks -- this was brief and clear enough that you should have put that into the OP, instead of making up a "pseudo/generic" case to confuse us. :) Anyway, I would tend to prefer taking a two-step approach: apply all the substitutions that work, and after those are all done, if any residual template-variable markers are left behind, then croak. Something like this: `my %hash = ( var1 => 'value1', var2 => 'value2' ); # ... or whatever... while ( $tmpl =~ /@~(.*?)~@/ and exists( $hash{$1} )) { my $var = $1; $tmpl =~ s/@~$var~@/$hash{$var}/g; } croak "Bad template text:\n$tmpl" if ( $tmpl =~ /@~\|~@/ );` [download] "Basic" regex substitutions tend to be obscure and cryptic enough by themselves, without adding flow-control logic into the rhs. The code will be easier to maintain if you segregate the regex operations from the flow-control.	[reply] [d/l]