Thanks for your reply.

So it is the Perl 6 equivalent to say sort {$a <=> $b} @array;?

But how is that statement related to the Schwartzian transformation?

The +* is a "key extractor" closure. This closure corresponds to the before map of the ST. Of course, in the specific case of +*, it's trivial to instead just specify a "comparator" closure using <=>, but what if one instead writes:

say sort +*.value, 1=>4,  11=>5,  2=>99,  22=>22,  3=>339
# prints           1=>4   11=>5   22=>22  2=>99    3=>339

say sort ~*.value, 1=>4,   11=>5,  2=>99,  22=>22,  3=>339
# prints           22=>22  3=>339  1=>4    11=>5    2=>99
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(And of course the results of the closure call on a given item is memoized.)

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»ö« ^{. o O ( "the celebrity tell-all of the Perl-6 cult?" )}

The default is to sort strings stringwise, and numbers number-wise. The +* just forces number comparison.