The hardest part is inverting the portions of the key which must sort descending.
If the entire key is descending, you don't need to invert it; just using sort { $b cmp $a } is good enough. sort will recognize that specific code and not actually call the code block.
--
A math joke: r = | |csc(θ)|+|sec(θ)| |-| |csc(θ)|-|sec(θ)| |

In reply to Re^2: Advanced Sorting - GRT - Guttman Rosler Transform by ysth
in thread Advanced Sorting - GRT - Guttman Rosler Transform by demerphq

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