== ruby_core_ri gem ==

This gem installs a local copy of the trunk RI, which is useful for those ruby distros that are lacking the core RI (ex: rubyinstaller).  

For example, if you get this:

$ ri File
Nothing known about File

$

Then after installing this gem, you will get the following (the ri is there now):

$ ri File
--------------------------------------------------- Class: File < Object

FTOOLS.RB: EXTRA TOOLS FOR THE FILE CLASS
=========================================

     Author:        WATANABE, Hirofumi

     Documentation: Zachary Landau
... [etc.]


The gem downloads the source for your current Ruby version, then does a gem --ri, thus installing the ri for Ruby's core docs locally, though really as a gem.

== Installation (takes a little while--it's worth it if you want to use ri for core classes, though) ==

$ gem install ruby_core_ri

$ ruby_core_ri # downloads your distro's sources, ri's them

* Note: for 1.9 users you have to install rdoc > 2.4.3 for it to work (possibly even > 2.5.0).  
  To do so (until bugs are fixed in rdoc trunk):

    $ gem install specific_install # install this gem plugin
    $ gem specific_install -l http://github.com/downloads/rdp/ruby_core_ri/rdoc-2.4.3.1.gem # install a slightly fixed version that actually works with trunk
    
    Or install that gem version by hand.

== Trouble Shooting ==

With gems v 1.3.6, gems now always "doesn't re-generate" ri and rdoc (even on failed attempts of the same).

So if you attempt an install and "nothing happens" ex:

$ gem rdoc --no-rdoc --ri ruby_core_ri

$ # note lack of output

Then you may have to uninstall the gem, or remove your equivalent of C:\Ruby19\lib\ruby\gems\1.9.1\doc\ruby_core_ri-0.4.0 before running ruby_core_ri again (then it will work).
You may also need to uninstall the mislav-hanna gem first, if you have it installed.