G'day Rolf,

"I have trouble finding a canonical explanation of Orcish Manoeuvre, ..."

"A Fresh Look at Efficient Perl Sorting" describes many sorting techniques. The section on OM points to a footnote with details of a book by the inventor of this algorithm. I don't own, nor have I read, this book, so I can't comment further.

"... but isn't Memoize faster in this case?"

Try Benchmark to answer that. Please post your results: I, and no doubt others, would be interested.

OM is basically ST, but where the sort is provided the default comparison function ($a cmp $b).

Technically, any of the four builtin compare functions would work equally fast.

• $a cmp $b
• $b cmp $a
• $a <=> $b
• $b <=> $a

See (Ovid) Re: Orcish Maneuver for an explanation and a reference to the source.

See also: Re^5: Create sort function from a text file (Sorting References: Schwartzian, GRT, Orcish, External, Parallel)

Thanks.

From my perspective: "Orcish" is just the inner workings of a sort based on a key-function, like in Sort::Key °

AFAIK is sorting by key functions the default in Python.

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

°) Tho Salva wasn't explict if the result of a key-function is cached in his implementation.