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

[Stas Bekman]

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...

_____________________________________________________________________
Stas Bekman              JAm_pH     --   Just Another mod_perl Hacker
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