pipe.rb

class Object
  def pipe
    yield self
  end
end

# From https://github.com/rspec/rspec-rails/pull/766/files

# Without Object#pipe
types = begin
          dirs = Dir['./spec/**/*_spec.rb'].
            map { |f| f.sub(/^\.\/(spec\/\w+)\/.*/, '\\1') }.
            uniq.
            select { |f| File.directory?(f) }
          Hash[dirs.map { |d| [d.split('/').last, d] }]
        end

# With Object#pipe
types = Dir['./spec/**/*_spec.rb'].
          map { |f| f.sub(/^\.\/(spec\/\w+)\/.*/, '\\1') }.
          uniq.
          select { |f| File.directory?(f) }.
          map { |d| [d.split('/').last, d] }.
          pipe { |type_and_dirs| Hash[type_and_dirs] }

# With Enumerable#inject
types = Dir['./spec/**/*_spec.rb'].
          map { |f| f.sub(/^\.\/(spec\/\w+)\/.*/, '\\1') }.
          uniq.
          select { |f| File.directory?(f) }.
          map { |d| [d.split('/').last, d] }.
          inject({}){ |h, type_and_dirs| h.merge! Hash[*type_and_dirs]; h }
#p types

# with_object
types = Dir['./spec/**/*_spec.rb'].
          map { |f| f.sub(/^\.\/(spec\/\w+)\/.*/, '\\1') }.
          uniq.
          select { |f| File.directory?(f) }.
          map { |d| [d.split('/').last, d] }.
          to_enum.
          with_object({}){ |type_and_dirs, h| h.merge! Hash[*type_and_dirs] }
p types


types = Dir['./spec/**/*_spec.rb'].
          map { |f| f.sub(/^\.\/(spec\/\w+)\/.*/, '\\1') }.
          uniq.
          select { |f| File.directory?(f) }.
          map { |d| [d.split('/').last, d] }.
          tap { |type_and_dirs| break Hash[*type_and_dirs.flatten] }
p types