[OT] How to write this perl sub w/o variables?

[Philip Mak <pm...@aaanime.net>]

Is it possible to rewrite this perl subroutine without using variables?

sub XMLEncode {
    my ($line) = @_;
    $line =~ s/&/&/g;
    $line =~ s/</&lt;/g;
    $line =~ s/>/&gt;/g;
    return $line;
}

I was thinking something like

sub XMLEncode {
    s/&/&amp;/g;
    s/</&lt;/g;
    s/>/&gt;/g;
    return $_;
}

but I can't get it to work like that.

-Philip Mak (pmak@aaanime.net)

Re: [OT] How to write this perl sub w/o variables?

[Honza Pazdziora <ad...@informatics.muni.cz>]

On Sun, Apr 29, 2001 at 04:34:40AM -0400, Philip Mak wrote:
> 
> I was thinking something like
> 
> sub XMLEncode {

	local $_ = shift;

>     s/&/&/g;
>     s/</&lt;/g;
>     s/>/&gt;/g;
>     return $_;
> }

-- 
------------------------------------------------------------------------
 Honza Pazdziora | adelton@fi.muni.cz | http://www.fi.muni.cz/~adelton/
   .project: Perl, DBI, Oracle, MySQL, auth. WWW servers, DBD::XBase.
------------------------------------------------------------------------

Re: [OT] How to write this perl sub w/o variables?

[Stas Bekman <st...@stason.org>]

On Sun, 29 Apr 2001, Philip Mak wrote:

> Is it possible to rewrite this perl subroutine without using variables?
>
> sub XMLEncode {
>     my ($line) = @_;
>     $line =~ s/&/&/g;
>     $line =~ s/</&lt;/g;
>     $line =~ s/>/&gt;/g;
>     return $line;
> }
>
> I was thinking something like
>
> sub XMLEncode {
>     s/&/&amp;/g;
>     s/</&lt;/g;
>     s/>/&gt;/g;
>     return $_;
> }
>
> but I can't get it to work like that.

don't reinvent the wheel, use CPAN:

# get the encoding sub right
if ($ENV{MOD_PERL}) {
    require Apache::Util; # much faster! XS/C code!
    *encode = \&Apache::Util::escape_html;
} else {
    require HTML::Entities;
    *encode = \&HTML::Entities::encode;
}

then call encode($mytext);

not talking about the fact that your code is highly inefficient (you run
s/// 3 times!!!), at least use a hash:

%map = (
  '&' => '&amp',
  '<' => '&lt',
  '>' => '&gt',
);

sub encode { $_[0] =~ s/(&|<|>)/$map{$1}/g; }

note that this will fail: encode("hello"), because you will try to modify
a constant string (versus, $a = 'hello'; encode($a)).

hope this helps...

_____________________________________________________________________
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