Regexp Named groups not working

[m0rkeulv]

Describe the bug

Flash accepts regexp with named groups and these can be accessed as either indexed elements or properties on the returned object. Flash uses the ?P<name> syntax for defining named groups but this does not work with ruffle and it fails to handle these kind of regular expressions resulting in exec() returning null.

Expected behavior

when named groups are pressent Flash returns result/object while Ruffle returns null.

var namedGroup = /my(?P<groupName>Str)$/m; 
var namedExec = namedGroup.exec("myStr");

trace("index:"+namedExec[1]); //  Flash results in "index:Str" 
// Ruffle : Error #1009: Cannot access a property or method of a null object reference.

trace("named:"+namedExec.groupName); //Flash results in "named:Str"
// Ruffle  Error #1009: Cannot access a property or method of a null object reference.

Affected platform

Desktop app

Operating system

Windows 10

Browser

No response

Additional information

using the named group syntax that the library that ruffle expects (?<name>) do result in named group for the internal structure but it looks like ruffle dont propagate these to the object that is returned so even if the syntax mismatch was to be resolved ruffle still would not allow you to access the named groups by name.

var namedGroup = /my(?<groupName>Str)$/m; 
var namedExec = namedGroup.exec("myStr");
trace("index:"+namedExec[1]); //  the group got a match
trace("named:"+namedExec.groupName); // however the named property does not exists and returns undefined"

[torokati44]

While we currently rely on regress for this, the possibility of switching to the regex crate instead came up on Discord, so this might be relevant in that case: rust-lang/regex#956

[thaliaarchi]

@torokati44 Although regex supports this particular syntax for named capture groups, regress supports backreferences, a far more consequential feature, which regex intentionally does not support.