1sort(3pm) Perl Programmers Reference Guide sort(3pm)
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6 sort - perl pragma to control sort() behaviour
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9 The sort pragma is now a no-op, and its use is discouraged. These three
10 operations are valid, but have no effect:
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12 use sort 'stable'; # guarantee stability
13 use sort 'defaults'; # revert to default behavior
14 no sort 'stable'; # stability not important
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17 Historically the "sort" pragma you can control the behaviour of the
18 builtin sort() function.
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20 Prior to v5.28.0 there were two other options:
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22 use sort '_mergesort';
23 use sort '_qsort'; # or '_quicksort'
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25 If you try and specify either of these in v5.28+ it will croak.
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27 The default sort has been stable since v5.8.0, and given this
28 consistent behaviour for almost two decades, everyone has come to
29 assume stability.
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31 Stability will remain the default - hence there is no need for a pragma
32 for code to opt into stability "just in case" this changes - it won't.
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34 We do not foresee going back to offering multiple implementations of
35 general purpose sorting - hence there is no future need to offer a
36 pragma to choose between them.
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38 If you know that you care that much about performance of your sorting,
39 and that for your use case and your data, it was worth investigating
40 alternatives, possible to identify an alternative from our default that
41 was better, and the cost of switching was worth it, then you know more
42 than we do. Likely whatever choices we can give are not as good as
43 implementing your own. (For example, a Radix sort can be faster than
44 O(n log n), but can't be used for all keys and has larger overheads.)
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46 We are not averse to changing the sort algorithm, but we don't see the
47 benefit in offering the choice of two general purpose implementations.
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50 The function sort::current() was provided to report the current state
51 of the sort pragmata. This function was not exported, and there is no
52 code to call it on CPAN. It is now deprecated, and will warn by
53 default.
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55 As we no longer store any sort "state", it can no longer return the
56 correct value, so it will always return the string "stable", as this is
57 consistent with what we actually have implemented.
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61perl v5.38.2 2023-11-30 sort(3pm)