From: Simon Strandgaard <neoneye@...>
Date: 2004-01-21T06:55:01+09:00
Subject: enable debugflag in module

To ease unittesting I have made a #debug keyword, which enables 
the global $debug flag for the specified method.

For instance
    debug :test
is roughly equivalent with
    def test
        $debug = true
        super
        $debug = false
    end

The "debug" keyword works inside classes. But not within modules.
Question: How can I make "debug" work within modules ?

--
Simon Strandgaard


server> ruby a.rb
before #test
42
after #test
server> expand -t4 a.rb 
class Object
    # enable the global debug flag for just a single method
    def self.debug(*args)
        args.each{|symbol| 
            begin
                meth = instance_method(symbol)
            rescue => e
                $stderr.puts "ERROR: symbol2method failure, " + e.inspect
                next
            end  
            name = symbol.id2name
            org = "_debug_"+name
            arguments = (meth.arity != 0) ? "(*a,&b)" : "(&b)"
            module_eval <<MSG
            alias #{org} #{name}
            def #{name}#{arguments}
                $stdout.puts("before ##{name}")
                $debug = true
                #{org}#{arguments}
                $stdout.puts("after ##{name}") 
            ensure
                $debug = nil
            end
            private :#{org}
MSG
        }
    end
end

class Test
    module A
        def test
            p 42
        end
        #debug :test     # Why does'nt this work?
    end

    include A
    debug :test 
end

Test.new.test
server>