Here's an excerpt from chapter 7 (substitution):

Example 7.4 Sorting text by length for use in a regex.

  $keys =
    join '|',                           # 4
    map  { quotemeta }                  # 3
    sort { length($b) <=> length($a) }  # 2
    keys %change;                       # 1
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1. We get the list of keys from the hash – these are the strings...
2. We sort the keys by their length, so that the longest strings come first...
3. We run them through the quotemeta() function to make them safe for regexes...
4. And then we join the regex-safe strings with "|" in between them, for regex alternation.

Doing a benchmark, I see that the reverse sort LIST method is (as one would imagine) faster than the sort { length($b) <=> length($a) } LIST method (by more than two times). I'll incorporate your code, tilly, if'n you don't mind. :)

_____________________________________________________
Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
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