From: Jean-Hugues ROBERT <jean_hugues_robert@...>
Date: 2004-06-15T05:17:25+09:00
Subject: Re: method_missing and send

At 20:13 14/06/2004 +0900, you wrote:
>I'm in the process of writing a logging package for a project. The actual
>logging methods can be specified at runtime and are implemented with a class
>method_missing call.
>
>That works fine until I call the warn method using 'send'. I would have
>expected the object to respond identically to both the direct invocation and
>the indirect invocation via 'send'.
>
>Is this a bug in ruby or have I missed something?
>
>class B
>  def self.method_missing(sym, *args)
>    puts "%s: %s"%[sym, args[1]]
>  end
>end
>
>B.log(self, "There was a young man called McKnight,")
>B.send(:log, self, "Who could travel faster than light.")
>B.warn(self, "One day at about noon, he went to the moon")
>B.send(:warn, self, "And arrived back the previous night.")
>
>bash-2.05b$ ruby -v
>ruby 1.8.1 (2004-01-27) [i386-mswin32]
>bash-2.05b$
>bash-2.05b$ tmp.rb
>log: There was a young man called McKnight,
>log: Who could travel faster than light.
>warn: One day at about noon, he went to the moon
>../tmp.rb:71:in `warn': wrong number of arguments(2 for 1) (ArgumentError)
> from ./tmp.rb:71:in `send'
> from ./tmp.rb:71
>bash-2.05b$
>
>
>Neil.

Hi,

As a side note, you may want to consider a solution
using blocks:

def trace( domain = :debug, &block )
  if $domains[domain] then
    p block.call()
  end
end

trace{ "debug"}
trace( :info){ "Hello"}
trace( :warn){ "fast" }

Doing so is rather efficient when the said domain is disabled.
As a result you can keep traces in production code.

You can even:

def off( domain )
  if domain == :trace then
    alias trace noop
  end
  $domains[domain] = false
end

def noop( *a ); end

...

off( :trace) # turns all tracing off

Yours,

JeanHuguesRobert

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