Problem Statement

Idiomatically determine all the lowercase and uppercase letters   (of the Latin [English] alphabet)   being used currently by a computer programming language. The method should find the letters regardless of the hardware architecture that is being used (ASCII, EBCDIC, or other).

Display the set of all: that can be used (allowed) by the computer program, where   letter   is a member of the Latin (English) alphabet:     a ──► z     and     A ──► Z.

You may want to mention what hardware architecture is being used, and if applicable, the operating system.

Let's start with the solution:

given (0..0x1fffd).chrs {
    say "Lowercase: ", .comb(/<:Ll>/);
    say "Uppercase: ", .comb(/<:Lu>/);
    say "Titlecase: ", .comb(/<:Lt>/);
}