From: transfire@...
Date: 2006-06-30T18:53:31+09:00
Subject: Prime mark for method wrapping

Had a thought today about the idiom:

  alias :foo_without_bar, :foo
  def foo
    ...
    foo_withiout_bar
    ...
  end

First let me point out that Rails recently invented a further bent on
this:

  def foo_with_bar
    ...
    foo_withiout_bar
    ...
  end

  alias_method_chain :foo, :bar

The trick is the last method which is equivalent to:

  alias_method :foo_without_bar, :foo
  alias_method :foo, :foo_with_bar

This new idiom is useful when including modules by adding it to the
#included callback. This wookrs finr for the specialized use it gets in
Rails, but it really has issues as a general solution. But I won't go
into that. That's not the point of this thread.

This morning it occured to me that an elegant solution might be the use
of a prime mark to do true method wraps:

  def foo'
    ...
    foo
    ...
  end

This is essentially like matz 'def foo:wrap' but without the extraneous
label. Of course matz hints at having some general use for that label,
if so, I sure would like to know what it is.

Anyhow, just a thought.

T.