I tried this:
re_operator := regexp.MustCompile("^(+|-|*|/)")
I get this:
panic: regexp: Compile(`^(+|-|*|/)`): error parsing regexp: missing argument to repetition operator: `+`
It's literally impossible to Google an answer to this question, not to mention it varies for every language and version. I'm about to use an if else. Escape sequences are also a pain. Should I try escaping my escape sequence?
Unhelpful answer: Regular expression to match digits and basic math operators