Index Submatch (${1}) does not work as expected

[oliverisaac]

Hello,

When I try to use a regex with an index submatch, the index submatch has an "off by two" behavior.

I would expect this to work:

However, autolink is adding extra parenthesis around the regex, so instead I have to do this:

(Note the ${3})

This can be reproduced using this sequence of commands:

/autolink add submatch
/autolink set submatch Pattern prefix/(.*)
/autolink set submatch Template final/${1}
/autolink test submatch prefix/hello

/autolink set submatch Template final/${3}
/autolink test submatch prefix/hello

I acknowledge I can use named submatch groups but the golang regex dialect isn't portable to the other languages we are using (ruby) so I'd like to use the numeric submatches instead.

Workarounds

• Ruby doesn't support (?P<name>submatch) syntax for subgroups, but grep -P does
• We can use the off-by-2 index, but it's unintuitive when writing the code and prone to error

This isn't a blocker for me, but figured I'd drop this here. At the very least, maybe we update the README so it calls out this unexpected behavior?