在Or Regex中使用带有| |的组

Question

Is there a way in Go Regex if I have (a)|(b) to start groups for b also with 0 ? how would I do that?

re := regexp.MustCompile(
   `<(\$)([a-zA-Z0-9]+):([a-zA-Z0-9]+):([a-zA-Z0-9]+)>|{(@)([a-zA-Z0-9 ]+)}`)

and iterate over with

for _, v := range re.FindAllSubmatchIndex([]byte(str), -1) {
  ...
}

How do I "normalize" groups (indexes)? so the (@) is also group 0?

Can i use groupnames with the same names?

Answer 1

Go regex engine is RE2, and infortunately it does not support the feature you are looking for, namely, a branch reset group.

There are PCRE library ports for Go if you need it by all means. Here is a package pcre library, for example. Once added, you can use

(?|<(\$)([a-zA-Z0-9]+):([a-zA-Z0-9]+):([a-zA-Z0-9]+)>|{(@)([a-zA-Z0-9 ]+)})
^^^                                                  ^                    ^

See the regex demo.