Is my interpretation of the zero-length matches for the regex `|` correct?

Question

The regexp | seems to match everything that's empty. my best guess at an interpretation of the regexp | is that it's saying: match either "nothing" or "nothing". So it ends up matching every zero-length spot in the string. Would this be the correct interpretation?

Some sample Go code using this regexp that shows what I'm talking about: https://play.golang.org/p/5JzeMkuMcnr

Answer 1

Yes, the empty regex matches 0 characters at any position, and the regex | is just the alternation of two empty regexes, which is the same thing (since the first branch of the alternation trivially matches).