You are right it's in >99% of the cases redundant.

IMHO it doesn't really matter what other cases are, what matters is that they are extremely rare.

That's why another approach is sorting with "key functions", which is not only shorter but also faster.

tldr

For a deeper understanding it's worth looking over the fence.

Python (among other languages) has key functions and Salva implemented them with Sort::Key.

But why does Salva's implementation provide a zoo of different functions making it more difficult to grasp?

Because comparisons in Perl are operator based while Python is typed based. (There is no eq in Python, a value is a string or not)

Hence Salva needs to implement keysort nkeysort to reflect the differences between == and eq ... In Python they rely on the implicit type.

And he needs rkeysort rnkeysort to reverse the sort order.

IMHO

A perfect solution in Perl would involve an additional Sort::Key like solution, with a syntax reusing the established operators cmp and <=> plus an easy way to indicate reversing the sort order.

Cheers Rolf
(addicted to the Perl Programming Language :)
see Wikisyntax for the Monastery

In reply to Re: Notation of sort function (Sort::Key) by LanX
in thread Notation of sort function by Alphaphi

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.