From: Wyatt Greene <greenewm@...>
Date: 2008-01-31T00:09:57+09:00
Subject: Re: Start and stop a ruby loop ;(

You're almost there.  First of all, in Ruby, you don't declare your
instance variables outside of methods.  You just set them inside of a
method, and they get automatically declared.  For example:

class Foo

  def bar
    @baz = 3
  end

  def qux
    @quux = 4
  end

  def show_me
    p @baz
    p @quux
  end

end

If you say:

a = Foo.new
a.show_me

It should print:

nil
nil

Because the object's instance variables of @baz and @quux haven't been
initialized.  If you say:

a = Foo.new
a.bar
a.show_me

It should print:

3
nil

because when the bar method was called, it initialized the @baz
variable to 3.  Likewise, if you say:

a = Foo.new
a.bar
a.qux
a.show_me

You will get:

3
4

Also, it looks like you want to use a while loop instead of a for
loop.  So for your example, you could do this:

class MyFirstClass

   def start_my_loop
     while !@stop_loop
       puts 'Im inside the loop..............'
     end
   end

   def stop_my_loop
     @stop_loop = true
   end

end

Notice that when you call start_my_loop, if @stop_loop hasn't yet been
initialized, its value is nil.  This means that it will begin
executing the loop.  If you wanted to explicitly set the value of
@stop_loop from the get-go, then use a constructor:

class MyFirstClass

   def initialize
     @stop_loop = false
   end

   def start_my_loop
     while !@stop_loop
       puts 'Im inside the loop..............'
     end
   end

   def stop_my_loop
     @stop_loop = true
   end

end

So now you can use this code like this:

a = MyFirstClass.new
a.start_my_loop
a.stop_my_loop

However, this will not work.  Once the program enters the loop, it
stays there.  You need some way to pass control of the program to
outside of the loop, otherwise, you'll be looping forever.  One way to
do this is to use multiple threads.  Another way is to use blocks,
like this:

class MyFirstClass

   def start_my_loop
     while yield
       puts 'Im inside the loop..............'
     end
   end

end

a = MyFirstClass.new
a.start_my_loop do
  if rand(5) == 3
    false
  else
    true
  end
end

Every time the program gets to the yield statement, it calls the block
that you passed to the start_my_loop method.  This block randomly
returns true or false.  If it returns true, the loop is executed
again.

I hope this was helpful!

Cheers,
Wyatt Greene



On Jan 30, 8:44 am, Sameera Gayan <sameera...@hotmail.com> wrote:
> Hi all,
>
> I have the following loop
>
> class myFirstClass
>    is_loop = 0
>
>    def start_my_loop
>      for is_loop < 1
>        puts 'Im inside the loop..............'
>      end
>    end
>
> end
>
> i can start above class's loop by using following...
>
> require 'myFirstClass'
> class mySecondClass
>    oFirst = myFirstClass.new
>    oFirst.start_my_loop
> end
>
> and i need a way to stop the above loop from calling another method.
> Like...
> calling a nother method to make the 'is_loop' to 1
>
> but the problem is when i use the
> myFirstClass.new --> is_loop to 0
>
> so can anyone tell me a way to do this. I want to start the loop from
> one method and stop it from another. (Or what is the way to do this)
>
> I'm sorry if i'm doing something wrong coz i'm nwe to ruby
>
> thankx in advance
>
> cheers
> sameera
> --
> Posted viahttp://www.ruby-forum.com/.