RDoc::usage was removed from ruby at the beginning of 2008, and thus is
not present in Ruby 1.9.1:
Fri Jan 11 18:28:49 2008 Eric H.
* lib/rdoc/usage.rb: Removed.
* lib/getoptlong.rb: Update example to not use
It was a very useful function that allowed documentation in rdoc format
to be programmatically output. I’ve been using it for displaying
extended information either after an OptionsParser help summary output
or as a replacement when OptionsParser’s output isn’t suitable. It’s
also very useful for other information-display reasons where you want
information in rdoc format to also be programmatically available to
It seems a shame that it has gone, especially as it is documented in the
pickaxe book (second edition) and is widely deployed.
What is a suitable replacement?