As Go's regular expressions are based on RE2, I always use the latter's documentation page <https://github.com/google/re2/wiki/Syntax> to check what is and isn't allowed.
Note though that: \C, which RE2 normally allows, isn't allowed in Go. Alan On Tuesday, January 7, 2020 at 6:21:58 PM UTC, Tom Payne wrote: > > Hi, > > tl;dr How should I use named Unicode character classes in regexps? > > I'm trying to write a regular expression that matches Go identifiers > <https://golang.org/ref/spec#Identifiers>, which start with a Unicode > letter or underscore followed by zero or more Unicode letters, decimal > digits, and/or underscores. > > Based on the regexp syntax <https://godoc.org/regexp/syntax>, and the > variables > in the unicode package <https://golang.org/pkg/unicode/#pkg-variables> which > mention the classes "Letter" and "Number, decimal digit", I was expecting > to write something like: > > identiferRegexp := > regexp.MustCompile(`\A[[\p{Letter}]_][[\p{Letter}][\p{Number, decimal > digit}]_]*\z`) > > However, this pattern does not compile, giving the error: > > regexp: Compile(`\A[[\p{Letter}]_][[\p{Letter}][\p{Number, decimal > digit}]_]*\z`): error parsing regexp: invalid character class range: > `\p{Letter}` > > Using the short name for character classes (L for Letter, Nd for Number, > decimal digit) does work however: > > identiferRegexp := regexp.MustCompile(`\A[\pL_][\pL\p{Nd}_]*\z`) > > You can play with these regexps on play.golang.org > <https://play.golang.org/p/WITTbqvom9F>. > > Is this simply an oversight that Unicode character classes like "Letter" > and "Number, decimal digit" are not available for use in regexps, or should > I be using them differently? > > Many thanks, > Tom > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/e6307afc-889c-46de-87b0-6f9a06620421%40googlegroups.com.
