From: Kero van Gelder <kero@...4050.upc-d.chello.nl>
Date: 2001-09-01T03:21:25+09:00
Subject: [ruby-talk:20637] Re: Passing procedures

> I am building this class that takes a user defined procedure and then
> applies it. The test code looks like this:
> 
> class TestClass
>  def initialize(&process)
>   @process = process
>  end
> 
>  def run()
>   if @process == nil then
>    puts "No process given"
>   else
>    @process.call(self, "this", "that")
>   end
>  end
> end
> 
> def testfunc(a, b)
>  puts "1 -> #{a} 2 -> #{b}"
> end
> 
> fred = TestClass.new(testfunc)
> fred.run
> 
> I am expecting the message "1 -> this 2 -> that", what I get is:
> 
> test.rb:19:in `testfunc': wrong # of arguments(0 for 2) (ArgumentError)
>         from test.rb:19
> 
> The problem is the fred = TestClass.new(testfunc) line. It will work if I
> put in some parameters but I want the parameter values set when it is called
> inside the class, if I declare them on line 19 then I only get those values
> back.

you are confusing methods and proc:

  testproc = proc { |a, b|
    puts "1 -> #{a} 2 -> #{b}"
  }
  fred = TestClass.new(&testproc)

and because it is no method, @process.call("this", "that") is enough.

+--- Kero ------------------------------ kero@chello.nl ---+
|  Don't split your mentality without thinking twice       |
|                          Proud like a God -- Guano Apes  |
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