From: Phrogz <gavin@...>
Date: 2006-12-30T08:50:07+09:00
Subject: Re: Methods validating their arguments: good or bad?

Vincent Fourmond wrote:
> def method(a)
> entry_check
>   a.is_a(String)
> begin
>   # now do something with code
> exit_check
>   # a test on exit
> end

An idea:

  if $DEBUG
    def entry_check; yield; end
  else
    def entry_check; end
  end
  alias_method :exit_check, :entry_check

  def method( a )
    entry_check{
      raise "OUCH" unless a.is_a?( String )
    }
    # meat here...
    exit_check{
      # ...
    }
  end

When the debug flag is supplied, the block is yielded and run. When
not, the entry_check call still does have the overhead of a do-nothing
method call, but far less than before.