Re^2: Sort command equivalent in perl

[MidLifeXis]

in reply to Re: Sort command equivalent in perl
in thread Sort command equivalent in perl

Will the sort still happen in memory? If it is not in memory, I do not see how this can do the @file = sort @file without data loss. If it is in memory, we are back to the original problem.

+1 for the unique approach.

[BrowserUk]

You're right. it wouldn't work for files greater than memory.

I thought it might for a while because of the in-place sort optimisation that came in somewhere in 5.8.x, that means that:

@ar = sort @r;

gets converted to sort \@ar; and sorts in place rather then copies the array to the stack and back.

But looking at the code, it doesn't work for tied arrays:

    /* optimiser converts "@a = sort @a" to "sort \@a";
     * in case of tied @a, pessimise: push (@a) onto stack, then assig
+n
     * result back to @a at the end of this function */

[davido]

Yup, there's the gotcha that gotme. :) I remembered that @array = sort @array doesn't make a copy, but failed to think through the fact that tie would be different.