Re: Regex in a variable

[John W. Krahn]

Paolo Gianrossi wrote:

Alright! This works... I solved the minor issue of modifiers and simple
matching instead of substitution (remember I need to take care of
*arbitrary* regexes) by:

my ($op, $replacement, $modifiers)=('', '');
if($rexp=~/^s(.)/){
   $op='s';
   my $delimiter=quotemeta($1);
  (undef, $rexp, $replacement, $modifiers) = split /$delimiter/, $rexp;
  if($modifiers) { $rexp = "(?$modifiers)$rexp";}
} else { ... # match other operations alike}

{no warnings 'regexp'; # this I need because I force /g... If user 
                       # enters /g as well, a warning (useless /g) is 
		       # raised.
  if($op eq 's') { #substitution... do something similar in 
                   # elsif branches for other ops
     while($text =~ s/$regex/$replacement/g){
        my $l=length($`);
        print substr($text, 0, $l);
        print ">";
        print substr($text, $l);
     }
  }
}

So this is fine. The minor issue I see is that this works great with all
delimiters but matching ones. Something in the lines of s(exp)(subs)
fails miserably... Still, I can survive with that.

It also doesn't work if there is whitespace between the operator name 
and the delimiter, for example: 'm / abc /x' or 's / abc /def/x'.

Or if the delimiter is part of the pattern, for example: 'm/..\/..\/../'.

Or if the /e option is used with the substitution operator.

(Or perhaps if the user wants to use tr/// instead of m// or s///?)



John
--
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order.                            -- Larry Wall

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