my $value = [ $x => $y ] -> [ $y <= $x ]; would not pass my code review.

I agree it’s confusing the first time and the => should be a skinny comma :P instead. That said, the Schwartzian transform is even more confusing the first time you see it. No one in a post 5.6 Perl world would suggest rewriting it with a bunch of temp arrays and for blocks. So, I advocate simple little idioms like the above when they offer something more than clever/pretty code.

So, thinking to possibly defend the clever/pretty one, I tried a Benchmark, which I'm not necessarily doing right so someone please jump in if it’s badly formed, and the one that might be the most semantically clear and I assumed would be the slowest is the fastest by a good measure. I forgot that List::Util is XS.

use strictures;
use Benchmark "cmpthese";
use List::Util "min"; # This is XS.

my @xy = ( [ 1, 0 ], [ 0, 1 ], [ 0, 0 ], [ 1, 1 ],
           [ 1_000_000, 999_999 ], [ 999_999, 1_000_000 ] );

my $m; # Avoid void in comparisons.
cmpthese(10_000_000, {
                   list_util => sub { $m = min(@$_) for @xy },
                   ternary => sub {
                       $m = $_->[0] < $_->[1] ? $_->[0] : $_->[1] for 
+@xy },
                   clever => sub {
                       $m = [ $_->[0], $_->[1] ]->[ $_->[0] <= $_->[1]
+ ] for @xy },
                  });

[download]
               Rate    clever   ternary list_util
clever     347584/s        --      -56%      -68%
ternary    792393/s      128%        --      -28%
list_util 1096491/s      215%       38%        --

[download]

In reply to Re^2: The Boy Scout Rule by Your Mother
in thread The Boy Scout Rule by eyepopslikeamosquito

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