Metaprogrammer

---

Install

Install from rubygems, the gem is named 'metaprogrammer'.

Usage

Metaprogrammer is a module. There are two main methods it exposes:

• patch_class_methods
• patch_instance_methods.

There is also a patch_all_methods method that has the same signature as the other two, and calls them both.

An example usage looks like this:

class MyClass
  extend Metaprogrammer
  def foo
    1
  end
  def self.foo
    1
  end
end

MyClass.patch_all_methods do |orig_method, **args, &blk|
  orig_method.call(**args, &blk) + 1
end

MyClass.foo # => 2
MyClass.new.foo # => 2

You can manipulate the arguments or the return value.

A couple example usages are included with the gem:

# Rescue all errors
MyClass.rescue_all_methods(RuntimeError) do |error|
  puts "#{error.class} was raised!"
end

# Memoize all methods
MyClass.memoize # memoizes all methods.

The implementations of these methods are pretty simple (assuming these are called in class scope of the method which extends Metaprogrammer)

# rescue all methods
patch_all_methods do |orig_method, *args, &caller_blk|
  begin
    orig_method.call *args, &caller_blk
  rescue *exceptions => e
    blk.call(e)
  end
end

# memoize methods
patch_all_methods do |orig_method, *args, &caller_blk|
  memos = @_memoized_methods ||= {}
  method_memos = @_memoized_methods[orig_method] ||= {}
  method_memos[args] ||= orig_method.call *args, &caller_blk
end

patch_all_methods, patch_class_methods, and patch_instance_methods can all be configured with only: and except: options. These should be given as arrays of symbols corresponding to method names.