Your x!! approach is nifty, but it's a little hard to read: the double-negation is confusing unless explained, and the x operator seems to be out of place in this context. I have always found one of these easier to read: 

my $uri;
foreach ( 
   'http://example.net/app',
   $is_admin_link && 'admin',
   $subsite, 
   $mode, 
   $id, 
   $submode,
) {
   $uri.="$_/" if ( defined $_ && length($_) ) #omit undef and empties
}

[download]

If you need to preserve the parts seperately: 

my @part = ( 
   'http://example.net/app', 
   $is_admin_link   && 'admin',
   $subsite,
   $mode,
   $id,
   $submode,
);

my $uri; 
foreach (@parts) { 
   $uri.="$_/" if ( defined $_ && length($_) ) #omit undef and empties
}

[download]

I prefer these because:

  1. The logic for inclusion of parts is clear
  2. It makes it easy to apply a common rule to all components (e.g. URL-ify components before concatenation)
  3. It avoids repetition of code
<–radiant.matrix–>
A collection of thoughts and links from the minds of geeks
The Code that can be seen is not the true Code
I haven't found a problem yet that can't be solved by a well-placed trebuchet

In reply to Re: Secret Perl Operators: the boolean list squash operator, x!! by radiantmatrix
in thread Secret Perl Operators: the boolean list squash operator, x!! by Aristotle

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