Module: Tweak::ObjectExtensions

Included in:
Object
Defined in:
lib/tweak.rb

Instance Method Summary collapse

Instance Method Details

#using(name) { ... } ⇒ Object

Temporarily augment the top-level classes/modules of the same name as those defined in the using-module for the duration of the block.

Examples:

module Tweaks
  class String
    def hello() :hello end
  end
end

using Tweaks do
  "john".hello #=> :hello
end

"john".hello #=> NoMethodError

Parameters:

  • name (Module, Symbol) —

    The using-module, may either be the name of the using-module as a Symbol or the actual Module itself

Yields:

  • The block where the functionality shall be available.

Returns:

  • The value of the block



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# File 'lib/tweak.rb', line 29

def using(name, &block)
  mod = name
  if name.instance_of?(Symbol)
    mod = Object.const_get(name)
  end
  
  raise "name is not a Module or a Symbol" if !mod.instance_of?(Module)

  tweaks = {}
  begin
    mod.constants.each do |v|
      tweaked_source = mod.const_get(v)
      
      # Only include the class/module from the using-module if:
      # 1. The class/module in the using-module is a module (or class)
      # 2. A corresponding module (or class) is found at top-level
      next if !tweaked_source.instance_of?(Module) && !Object.const_defined?(v) &&
        !Object.const_get(v).instance_of?(Module)
      
      tweak_dest = Object.const_get(v)
      tweak_source = mod.const_get(v)
      tweak_dest.gen_include(tweak_source)
      tweaks[tweak_dest] = tweaked_source
    end
    
    yield
    
  ensure

    # Uninclude all the using-module classes/modules
    tweaks.each do |tweak_dest, tweak_source|
      tweak_dest.uninclude(tweak_source, true)
    end
  end
end