I find it highly annoying that this, as far as I understand, really doesn't use regular expressions. The s/that/this/ syntax is not , of course, a regular expression. The regular expression is the thing that might go into the "that" part, an expression that can match against several different inputs. If all it supports is literals, it's not really worth calling it a regular expression, in my opinion. The article expr…
It is clearly not a regex engine, but it operates like a very very naive one, and uses the Perl syntax for them.
Ultimately Regex just seemed like the easiest / clearest way of describing the functionality. IE, if I say "Skype supports the Perl Regex syntax for simple word substitution" you probably instantly think of s/a/b/.
Maybe I should have used that as the headline, but it seemed a bit long.