[ANN] ruby_parser 3.12.0 Released

ruby_parser version 3.12.0 has been released!

* home: <https://github.com/seattlerb/ruby_parser>
* bugs: <https://github.com/seattlerb/ruby_parser/issues>
* rdoc: <http://docs.seattlerb.org/ruby_parser>

ruby_parser (RP) is a ruby parser written in pure ruby (utilizing
racc--which does by default use a C extension). RP's output is
the same as ParseTree's output: s-expressions using ruby's arrays and
base types.

As an example:

    def conditional1 arg1
      return 1 if arg1 == 0
      return 0
    end

becomes:

    s(:defn, :conditional1, s(:args, :arg1),
      s(:if,
        s(:call, s(:lvar, :arg1), :==, s(:lit, 0)),
        s(:return, s(:lit, 1)),
        nil),
      s(:return, s(:lit, 0)))

Tested against 801,039 files from the latest of all rubygems (as of 2013-05):

* 1.8 parser is at 99.9739% accuracy, 3.651 sigma
* 1.9 parser is at 99.9940% accuracy, 4.013 sigma
* 2.0 parser is at 99.9939% accuracy, 4.008 sigma

Changes:

### 3.12.0 / 2018-12-04

* 3 minor enhancements:

  * 2.5: Allow rescue/ensure/else in normal do blocks. (presidentbeef)
  * Added stabby proc with do/end as block call argument. (presidentbeef)
  * Holy cow levels of optimization from presidentbeef. I write slow bad code.

* 1 bug fix:

  * Improve handling of single-quoted symbols and labels. (mvz)