I've been poring over perldoc perlre as well as the Regular Expressions Cookbook and related questions on Stack Overflow and I can't seem to find what appears to be a very useful expression: how do I know the number of current match?
There are expressions for the last closed group match ($^N), contents of match 3 (\g{3} if I understood the docs correctly), $', $& and $`. But there doesn't seem to be a variable I can use that simply tells me what the number of the current match is.
Is it really missing? If so, is there any explained technical reason why it is a hard thing to implement, or am I just not reading the perldoc carefully enough?
Please note that I'm interested in a built-in variable, NOT workarounds like using (${$count++}).
For context, I'm trying to build a regular expression that would match only some instances of a match (e.g. match all occurrences of character "E" but do NOT match occurrences 3, 7 and 10 where 3, 7 and 10 are simply numbers in an array). I ran into this when trying to construct a more idiomatic answer to this SO question.
I want to avoid evaluating regexes as strings to actually insert 3, 7 and 10 into the regex itself.