Is there a cute Perl 6 way to take an array (say
‘a’..‘d’) and get all head/tail partitions of it (e.g.(<a>, <b c d>), (<a b>, <c d>), (<a b c>, <d>))?
Sure! Pick one:
my @a = ‘a’..‘e’; say (@a[^$_, $_..*] for 1..^@a);
my @b = ‘a’..‘e’; say (1..^@b).map: {@b[^$_, $_..*]};
my @c = ‘a’..‘e’; say (@c.rotor($_, ∞, :partial) for 1..^@c);
my @z = ‘a’..‘e’; say @z[0..*-2].keys.map: {@z[0..$_, $_^..*]}; # same as b
my @d = ‘a’..‘e’; say (1..^@d).map: {@d.rotor: $_, ∞, :partial};
my @e = ‘a’..‘e’; say (@e.head($_), @e.tail(@e - $_) for 1..^@e);
my @f = ‘a’..‘e’; say (|@f.rotor: $_, @f - $_ for 1..^@f).rotor: 2;
my @g = ‘a’..‘e’; say @g.keys.map: {@g[0..$_, $_^..*] if $_ < @g.end};
my @h = ‘a’..‘e’; say @h.keys.map: {@h.head($_), @h.tail(@h - $_) if $_};
my @i = ‘a’..‘e’; say @i.rotor(|(1..^@i Z (@i-1…0) »=>» -@i), ∞).rotor: 2;
my @j = ‘a’..‘e’; say ([\,] @j) Z (([\,] @j[1..*].reverse)».reverse).reverse;All should produce same output:
(((a) (b c d e)) ((a b) (c d e)) ((a b c) (d e)) ((a b c d) (e)))
However, not all of them are identical. Some may produce Seqs.
I remembered this from a few weeks back and with it created an example of utilizing Test::Lab. What better language than Perl 6 to have a framework for examining refactors/variations.