Class variable inside block of defining instance method

ruby-talk
1

Hello.

How do I perform something like this?

It's the @echo variable inside the block I'm talking about, how do I
gain "access" to it?

Sincerely,
phora.

···

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Posted via http://www.ruby-forum.com/.

2

This is not a class variable. It is an instance variable of @listen.

What kind of access do you need?

Kind regards

robert

···

2010/1/24 Mikkel Kroman <mk@maero.dk>:

How do I perform something like this?
gist:6a2aa7e86cad8717541f · GitHub

It's the @echo variable inside the block I'm talking about, how do I
gain "access" to it?

--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

3

Ruby doesn't scope quite like that normally, but you can do it using
instance_eval and define_method:

def initialize(server1, server2)
  @echo = echo = IRC::Client.new(*server1)
  @listen = IRC::Client.new(*server2)
  @echo.instance_eval do
    define_method :message_received do |nick, channel, message, *args|
      if channel == "#Pre"
        echo.puts("PRIVMSG #{echo.channel} :#{message}")
      end
    end
  end
end

instance_eval has some quirks, and define_method methods are never as
fast as normal methods (since they have full block dispatch
semantics), but this should do what you need.

- Charlie

···

On Sun, Jan 24, 2010 at 3:13 AM, Mikkel Kroman <mk@maero.dk> wrote:

Hello.

How do I perform something like this?
gist:6a2aa7e86cad8717541f · GitHub

It's the @echo variable inside the block I'm talking about, how do I
gain "access" to it?

Sincerely,
phora.
--
Posted via http://www.ruby-forum.com/\.

4

Unlikely, since the method was defined on @listen and not @echo. :slight_smile:
This is probably a better solution:

def initialize(server1, server2)
  @echo = IRC::Client.new(*server1)
  @listen = IRC::Client.new(*server2)

  class <<@listen
    attr_accessor :echo
  end
  
  @listen.echo = @echo
  
  def @listen.message_received(nick, channel, message, *args)
    if channel == "#Pre"
      echo.puts("PRIVMSG #{echo.channel} :#{message}")
    end
  end
end

Kind regards

robert

···

2010/1/25 Charles Oliver Nutter <headius@headius.com>:

Ruby doesn't scope quite like that normally, but you can do it using
instance_eval and define_method:

def initialize(server1, server2)
@echo = echo = IRC::Client.new(*server1)
@listen = IRC::Client.new(*server2)
@echo.instance_eval do
define_method :message_received do |nick, channel, message, *args|
if channel == "#Pre"
echo.puts("PRIVMSG #{echo.channel} :#{message}")
end
end
end
end

instance_eval has some quirks, and define_method methods are never as
fast as normal methods (since they have full block dispatch
semantics), but this should do what you need.

--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

5

Thanks to both of you, I've used both examples for several tasks.

···

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