Feature #1201

Add relative group reference in back reference with nest level in regular expressions (e.g. \k<-5+1>)

Added by Wolfgang NĂ¡dasi-Donner almost 8 years ago. Updated about 5 years ago.

Target version:


It should be possible to use relative group references in back reference with nest level.

Reason: As named in Ticket 1200 relative group references can be very helpful in writing subexpessions, which can be used later on as often as necessary in one regular expression.

Unfortunately back references with nest level, \k, \k, \k'n+level', and \k'n-level', do not allow relative group referencing, so they can only be used if one knows, how many normal groups are in the complete regular expression before the referenced group.

If there are relative group references possible, e.g. \k<-n+level>, \k<-n-level>, \k'-n+level', and \k'-n-level', these constructs can be used in subexpressions designed to be used more than once in a regular expression.

Related issues

Related to Ruby trunk - Feature #1200: Possibility for using named and normal groups together in regular expressions Rejected 02/25/2009


#1 Updated by Yui NARUSE over 7 years ago

This feature depends on oniguruma.

#2 Updated by Marc-Andre Lafortune over 7 years ago

  • Assignee set to Yukihiro Matsumoto
  • Target version changed from 1.9.1 to 2.0.0



#3 Updated by Shyouhei Urabe over 6 years ago

  • Status changed from Open to Assigned



#4 [ruby-core:42603] Updated by Yui NARUSE about 5 years ago

  • Status changed from Assigned to Closed

Ruby 1.9.1 supports this through Oniguruma 5.9.1.

Also available in: Atom PDF