regex looks like it has a bug about grouping but not capturing

[dzpao]

#help regex:

     { } embed a raw regular expression, matches are stored to %1-%99.
   %!{ } embed a raw regular expression, matches are not stored.

Minimal Workable Example:

2024-03-09 19:28:56 INPUT: #if { "foobar" == "{foo|bar}" } {#echo OK} {#echo BAD}
BAD
2024-03-09 19:29:00 INPUT: #if { "foobar" == "%!{foo|bar}" } {#echo OK} {#echo BAD}
OK

Since you can't use ^ and $ in #if, there is effectively no workaround for this error.

2024-03-09 19:36:10 INPUT: #if { "foobar" == "^%*{foo|bar}%*$" } {#echo OK} {#echo BAD}
BAD
2024-03-09 19:36:14 INPUT: #if { "foobar" == "^%*%!{foo|bar}%*$" } {#echo OK} {#echo BAD}
BAD

[dzpao]

I looked at the source code, and unlike {foo|bar} which would be compiled to ^(foo|bar)$, it seems that %!{foo|bar} is compiled to ^foo|bar$ instead of what I thought was ^(?:foo|bar)$, which led to me actually having to pass %!{(:?foo|bar)} in order to get to my goal, and to be honest, it looks kind of ugly.

[scandum]

It's explained in the help file:

[ ] . + | ( ) ? * are treated as normal text unlessed used within
braces. Keep in mind that { } is replaced with ( ) automatically
unless %!{ } is used.

[nyankers]

You can also do {?:foo|bar} since the { }s are replaced by ( )s verbatim.