Vmethods to add to 2.15

Hi Andy / Everyone,

While we're looking at a new release, perhaps now is a
proper time to get some vmethods in that seem to be missing
for everyone. I have added both substr for scalars and
delete for hash ops, as I'm sure many others have done.
(Actually I just looked at CVS and it looks like you already
added delete.)

my substr vmethod:
-----------------------------------------------
$Template::Stash::SCALAR_OPS-> =
  sub {
    my ($scalar, $offset, $length) = _;
    return substr($scalar, $offset, $length);
  };
-----------------------------------------------

In addition, I just had another thought of something that
seems to be missing and a cause of problems on the mailing
list occasionally. That would be missing back references in
replace regular expressions. So here is a possible new
vmethod called 'replace_backref' that would allow backref
replacement without the security problems associated with
backrefs. It's obviously not perfect, but I think if we just
documented the feature correctly, then people would know
what to expect. I also added a parameter to check globally
or not, which also might be a good feature to add to the
current replace. 

------------------------------------------------------------
$Template::Stash::SCALAR_OPS->{'replace_backref'}  = sub
{
  my ($str, $search, $replace, $do_global_match) = _;
  if (!defined($do_global_match)){
    $do_global_match = 1; #match globally by default.
  }

  $replace = '' unless defined $replace;
  return $str unless defined $str and defined $search;

  if ($do_global_match){
    $str =~ s!$search!
      my vals = ($1, $2, $3, $4, $5, $6, $7, $8, $9);
      my $template = $replace;
      $template =~ s/#(d+)#/$vals[$1 - 1] || ''/eg;
      $template;
    !ge;
  }else{
    $str =~ s!$search!
      my vals = ($1, $2, $3, $4, $5, $6, $7, $8, $9);
      my $template = $replace;
      $template =~ s/#(d+)#/$vals[$1 - 1] || ''/eg;
      $template;
    !e;
  }

  return $str;
};
------------------------------------------------------------

Here is an example of how it would be used:
------------------------------------------------------------
[% string = "Josh is an ok guy" %]
New String: [% string.replace_backref('^(w+ is)', '#1#
not') %]
Should Output: Josh is not an ok guy

[% string2 = 'Josh is not an ok guy' %]
New String: [% string2.replace_backref('(not) (an)', '#1#
#2#') %]
Should output original string2.
------------------------------------------------------------

I used d+ in the regexp up there, thinking that we may
later on add more than the 9 backrefs, but for now we could
just use [1-9].

Some things that would need to be documented are:
Downfalls:
*) If you want to use #d+# literally in your replace string
your sol. However, the user could simply use the normal
replace instead.
*) Takes longer than the normal replace cause of the extra
templating involved.
*) Currently only goes from 1-9 backrefs.

Options:
*) You can specify to not globally replace now.

I can pretty much guarantee people won't care about the
extra replace time as long as they are able to use their
back references. (Those that are concerned can simply
override the vmethod.)

Any thoughts/changes on this idea/patch are welcome. (ie:
different names for it, or maybe a different format than
#d+#.)

-- Josh

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Vmethods to add to 2.15

Thread: Vmethods to add to 2.15