From: Mike Harris <GENIE@...>
Date: 2007-01-13T05:31:11+09:00
Subject: Re: Rake, Hoe, Meta-Programming, and Warnings (oh my!)

Tim Pease wrote:

> Is there a way to disable specific warnings from within a Ruby program
> (not from the command line)?
>
> The warnings are coming from some meta-programming code that is
> redefining instance methods on the fly based on user input. So maybe a
> better question would be, is there a way to redefine methods without
> causing Ruby to spew out a warning each time the method is redefined.
>
> This is the result of using Hoe (thanks Ryan, Eric, and other sun
> deprived Rubyists) to run my unit tests. Hoe adds the -w flag to the
> Ruby interpreter when it runs tests. This is a good thing as it found
> several minor flaws in my code. But redefining methods is at the heart
> of what I'm trying to do.
>
>
> Example:
>
> class Pattern
>  def self.create_date_format_methods( pf )
>    module_eval <<-CODE
>      def pf.format_date
>        Time.now.strftime "#{pf.date_pattern}"
>       end
>    CODE
>  end
> end
>
> When running unit tests with the -w flag ...
>
> (eval):1: warning: redefine format_date
>
>
>
> Any thoughts on how to suppress the warning and/or change my
> meta-programming so the warning does not show up?
>
> Blessings,
> TwP
>
>
I understand that this isn't identical to what you're doing, but it 
demonstrates how define_method won't cause a warning.

class Foo
  define_method(:bar) do  
    puts "bar"
  end
  def cat
    puts "cat"
  end
end

Foo.new.bar
Foo.new.cat

class Foo
  define_method(:bar) do  
    puts "bar2"
  end
  def cat
    puts "cat2"
  end
end

Foo.new.bar
Foo.new.cat

 >ruby -w foo.rb
bar
cat
foo.rb:17: warning: method redefined; discarding old cat
bar2
cat2