/ 
tap-0.01
/ tap

NAME

tap - add a tap method everywhere

VERSION

version 0.01

SYNOPSIS

use tap;

return Some::Class->new
  ->tap::color('red')
  ->tap::smell('roses');

# rather than:

my $o = Some::Class->new;
$o->color('red')
$o->smell('roses');
return $o;

DESCRIPTION

tap is a method that wraps any other method, ignoring its result and returning the invocant instead. This allows you to make chaining method out of anything, such a setters that return what you just set, or to peek into a method chain.

This module gets you access to tap anywhere, without requiring it to exist in a parent class or an imported lexical.

METHODS

tap::*

$o->tap::color('red')
  ->tap::smell('roses')
  ->...;

For use when you know what existing method you want to call. This is implemented using AUTOLOAD, which follows the common behavior of installing a method so you only fall to AUTOLOAD once.

It's not as fast as writing things out the long way, but it's the fastest of all tap-like features I've seen. And I think it's convenient while looking nice. I was using it in Reply for quite a while before making it a module.

tap::tap

$o->tap::tap($method => 42)->...;

# slip debugging into a chain
use DDP;
$o->tap::tap(\&p)->run;

For when the method name is dynamic, or you want to pass a coderef to be called as a method. For convenience the invocant is topicalized ($_) as well:

$o->tap::tap(sub { $_->foo->bar(42) })->run;

SEE ALSO

Object::Tap, Object::Util, Mojo::Base - other taps

curry - interface inspiration

PERFORMANCE

The following example benchmark (ex/bench.pl) was run with perl 5.26.0 on a 2015 MacBook Pro.

                  Rate tap-tap Object::Tap tap-reftap own-tap tap-autoload no-tap
tap-tap       650759/s      --         -1%        -5%    -14%         -30%   -49%
Object::Tap   656455/s      1%          --        -5%    -13%         -29%   -48%
tap-reftap    688073/s      6%          5%         --     -9%         -26%   -46%
own-tap       755668/s     16%         15%        10%      --         -18%   -40%
tap-autoload  925926/s     42%         41%        35%     23%           --   -27%
no-tap       1265823/s     95%         93%        84%     68%          37%     --
perl -l ex/bench.pl  26.30s user 0.04s system 99% cpu 26.362 total

As mentioned earlier, the fastest case no-tap is just not using tap - but where's the fun in that?

The three slowest cases are "tap::tap", Object::Tap, and saving a reference to "tap::tap", similar to what you get with Object::Tap. The next case, own-tap, is just the object having its own tap method, which should also be similar to having it in a parent class. tap-autoload is "tap::*", which edges the others out by making the tap package its own sort of method lookup cache. The trade-off is a package that grows at runtime.

I'm open to any other ideas to do even better, I've considered some myself, but it's also not bad to just avoid using tap in very hot code.

AUTHOR

Meredith Howard <mhoward@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2019 by Meredith Howard.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.