javascript_object.rb

# Make Ruby Hashes look more like JavaScript objects. Uses
# instance_exec so you can store lambdas on the object and
# call them like methods
# 
# o = {}
# o.foo = 'foostring'
# o.bar = lambda { |s| s + foo }
# 
# o.bar('barstring') #=> 'barstringfoostring'

class Hash
  def method_missing(symbol, *args)
    m = symbol.to_s
    self[m[0...-1].to_sym] = args.first and return args.first if m =~ /=$/
    value = self[symbol]
    value.is_a?(Proc) ? instance_exec(*args, &value) : value
  end
end

# http://eigenclass.org/hiki/instance_exec
class Object
  module InstanceExecHelper; end
  include InstanceExecHelper
  def instance_exec(*args, &block) # !> method redefined; discarding old instance_exec
    mname = "__instance_exec_#{Thread.current.object_id.abs}_#{object_id.abs}"
    InstanceExecHelper.module_eval{ define_method(mname, &block) }
    begin
      ret = send(mname, *args)
    ensure
      InstanceExecHelper.module_eval{ undef_method(mname) } rescue nil
    end
    ret
  end
end