That appears to be absolutely classic, terse, ideal test code for this case and I think you deserve more ++s than the apparently single you got from me. I wish you would sign-in and participate with a username to bank the credibility and goodwill and perhaps develop friendships here. I have a fair amount of animosity for and mistrust of anonymous monks at this point. Love to see you leave that stable.

For the interested, I added this to visualize what’s going on–

$ perl -Mfeature=fc -Mcharnames=:full -Mv5.16
binmode STDOUT, ":encoding(UTF-8)";
say join " ", $_, lc, fc, uc for
    map chr,
    ord("\N{CYRILLIC CAPITAL LETTER A}")..ord("\N{CYRILLIC SMALL LETTE
+R YA}");
[download]

Came across this again and added the command line invocation to support the character names and the use of fc and say.