From: "Mauricio Fernández" <batsman.geo@...>
Date: 2004-09-28T17:16:17+09:00
Subject: Re: Binding of the Caller (redux)

On Tue, Sep 28, 2004 at 12:56:25PM +0900, Gavin Kistner wrote:
> I'm trying to use Florian's Binding.of_caller, and it ain't working. In 
> the code below, if I uncomment the Binding.of_caller line, I get the 
> error:
> 
> ./libs/binding_of_caller.rb:61:in `of_caller': Binding.of_caller used 
> in non-method context or trailing statements of method using it aren't 
> in the block. (ArgumentError)

The message is quite explicit *g*

> 
> #!/usr/local/bin/ruby
> 
> require 'libs/binding_of_caller'
> 
> module EventTarget
> 	def add_event_listener( name, callback )
> 		callbacks = ((@registered_events ||= {})[ name.to_s ] ||= 
> 		[]);
> 		callbacks.delete( callback )
> 		callbacks << callback
> 	end
> 	def dispatch_event( evt, source )
> 		callbacks = (@registered_events ||= {})[ evt.name ];
> 		return unless callbacks
> 		#evt.source = Binding.of_caller{ |b| eval("self", b) }
> 		evt.source = source
> 		callbacks.each{ |m|
> 			m.call( evt )
> 		}

try
        Binding.of_caller do |b|
			evt.source = eval("self", b)
			callbacks.each{|m| m.call evt }
		end
	end
	
> 	end
> end
> 
> class Event
> 	attr_accessor :name, :source, :change
> 	def initialize( name, change=nil )
> 		@name = name.to_s
> 		@change = change
> 	end
> end
> 
> class HTMLInput
> 	include EventTarget
> 	
> 	attr_reader :value
> 	def value=( v )
> 		@value = v
> 		evt = Event.new( 'change', v )
> 		dispatch_event( evt, self )
> 	end
> end
> 
> inp = HTMLInput.new
> inp.add_event_listener( 'change', Proc.new{ |e| puts "#{e.source} just 
> changed." } )
> inp.add_event_listener( 'change', Proc.new{ |e| puts "The new value is 
> #{e.change}." } )
> inp.value = 12
> 
> #=> #<HTMLInput:0x1c58e4> just changed.
> #=> The new value is 12
> 
> 
> --
> (-, /\ \/ / /\/
> 
> 

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