grep-gems.rb

#!/usr/bin/ruby
#
# greps the latest version of each gem for def, class, module and constants
# assumes you have a tmp dir under your home dir
# you can then grep this file in emacs for definitions and then you can click
# on them to go to the file
#
last=[]
results=Gem.path.map do |dir|
  Dir["#{dir}/gems/*-[0-9].[0-9]*/lib"].sort{|a,b|b<=>a}.reject do |gem|
    parts=gem.split('-')
    if last[0..-2] == parts[0..-2]
      true
    else
      last=parts
      false
    end
  end.sort{|a,b|a.casecmp b}
end

args=%w{rgrep -n -e ^\\s*\\(\\(class\\|module\\)\\s\\s*[A-Z]\\|def\\s\\|[:A-Z][:A-Z_0-9]*\\s*=\\)}+results.flatten
STDOUT.reopen("#{ENV['HOME']}/tmp/gem-tags",'w')
exec *args