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Re^4: sort +*, @array

by raiph (Chaplain)
on Dec 09, 2013 at 13:53 UTC ( #1066289=note: print w/replies, xml ) Need Help??

in reply to Re^3: sort +*, @array
in thread sort +*, @array

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

(And of course the results of the closure call on a given item is memoized.)

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Re^5: sort +*, @array
by hdb (Monsignor) on Dec 09, 2013 at 14:26 UTC

    Thanks for the explanation. So the link to the Schwartzian really is the fact that the items are automatically memoized.

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