Re: Does Perl 6 use $a and $b in sorting?

sort accepts something callable with an arity of 2.

Subroutines, blocks and pointies will do:

say sort { $^a cmp $^b }, 5, 3, 2, 6, 4
OUTPUT«(2 3 4 5 6)␤»

say sort { $^left cmp $^right }, 5, 3, 2, 6, 4
OUTPUT«(2 3 4 5 6)␤»

say sort -> $a, $b { $a cmp $b }, 5, 3, 2, 6, 4
OUTPUT«(2 3 4 5 6)␤»

sub foo($a, $b) { $a cmp $b }; say sort &foo, 5, 3, 2, 6, 4
OUTPUT«(2 3 4 5 6)␤»

The { $^a cmp $^b } form also creates a anonymous sub that has two
parameters, $^a and $^b.
The funny thing about these params is that their position in the
implicit signature is obtained by the
alphabetical order of the parameter names.

So, there are no $a and $b special variables, it is just the common way
of naming them.

Am 26.09.2015 um 18:00 schrieb Parrot Raiser:
> Because of the the special significance of $a and $b in Perl 5's sort
> comparison, I always avoid using the names in examples, lest it set a
> booby-trap for later.
>
> I've noticed "a" and "b' being used in some P6 examples. Are they no
> longer significant, or are they just a poor choice of identifier?