Start a Scala REPL with the highest version of each jar in $HOME/.ivy2/cache on the classpath

scala_repl.rb

#!/usr/bin/env ruby

################################################################################
#                                                                              #
#         Starts a Scala REPL with the highest version of each jar in          #
#                     $HOME/.ivy2/cache on the classpath.                      #
#                                                                              #
#                   See below for installation instructions                    #
#                                                                              #
################################################################################

scala_version = /version (\d+\.\d+)/i.match(`scala -version 2>&1`)[1].to_sym
version_exclusions = {
  :"2.10" => ['2.11', '2.12'],
  :"2.11" => ['2.10', '2.12'],
  :"2.12" => ['2.10', '2.11']
}

jars = Dir["#{ENV['HOME']}/.ivy2/cache/**/*.jar"]
  .select { |j| !!(j =~ /\d+\.\d+(\.\d+)?(-((M|(RC))\d+)|SNAPSHOT)?\.jar$/i) }
  .reject { |j| !!(j =~ /(scala_)?(#{version_exclusions[scala_version].map { |e| Regexp.escape(e) }.join('|')})(-)?/i) }
  .group_by { |j| j.split('/').last.split(/\d\./)[0] }
  .values
  .map { |js| js.max_by { |j| Gem::Version.new(/([\d\.]+)\.jar$/i.match(j)[1]) } }

exec("scala -cp #{jars.join(':')}")

__END__

To install and run (requires ruby):

curl -sSL https://gist.github.com/mrdziuban/54098117df1c1511b782538e69ec4ab6/raw > ./repl \
  && chmod +x ./repl \
  && ./repl