You appear to have taken a side-issue and thrust it into the limelight.

The main focus of my post was about chaining. The opening sentence talked about performing all operations in a single statement. The code was all about chaining. The three documentation links I provided at the end lead to information about chaining.

And then there were side-issues:

I pointed out that I had used transliteration, instead of substitution (which the OP's code had), because it was quicker. That was an unequivocal statement.

[I didn't go into more depth on this issue as it detracted from the chaining operations I was demonstrating. However, it is documented in "perlperf - Perl Performance and Optimization Techniques" (specifically under "Search and replace or tr").]

I then went on to say that, if the OP chose not to use transliteration, then a character class might be quicker than alternation. I said "I expect" and "don't know for certain"; and went on to suggest benchmarking. There was no unequivocal statement here.