Note This SO should not have the raku tag. It is too obsolete/misleading. The technical problem discussed in the question body no longer applies. The disagreement in the comments about naming/tags no longer applies. I'm leaving it for historical interest only, under the old tag only.
I am learning Perl 6, and had trouble understanding the Perl 6 one-liner below
My Perl 6 is rakudo-star: stable 2014.04 (bottled)
This works fine. The array/list is sorted
[njia@mb-125:~] : perl6 -e 'say [2443,5,33, 90, -9, 2, 764].sort'
-9 2 5 33 90 764 2443
But this does not sort the array/list, if [].sort works why @s.sort does not?
[njia@mb-125:~] : perl6 -e 'my @s = [2443,5,33, 90, -9, 2, 764]; @s.sort.say'
2443 5 33 90 -9 2 764
Change from [] to ()
[njia@mb-125:~] : perl6 -e 'my @s = (2443,5,33,90,-9,2,764); @s.sort.say'
-9 2 5 33 90 764 2443
NOTE the described behavior in this question has changed in the release version of perl6. See response by G. Cito below.
For those who may be confused by this answer, the question is about Perl 6, and none of this applies to Perl 5.
The statement
my @s = [2443, 5, 33, 90, -9, 2, 764]
creates an itemised array and assigns it to @s[0], so @s has only a single element and sorting it is pointless.
However you can say
@s[0].sort.say
which has the effect you expected