Start and stop a ruby loop ;(

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

Hi Wyatt,

Thank you very much for your great help. It has lots of things to learn
for a beginner like me. So i will defiantly try these.

And thankx again for making it so clear

have a nice day

cheers
sameera

2008/1/30, Wyatt G. [email protected]:

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

Why make it more complicated than necessary?

a = MyFirstClass.new
a.start_my_loop do
rand(5) == 3
end

But I guess the OP rather wanted a concurrency solution.

Cheers

robert

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 G.

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