From: Foo <foo@...>
Date: 2004-07-18T00:53:26+09:00
Subject: Re: Having Trouble with IO.popen example

Thank You:)  That did the trick:)

SA



In article <40F931ED.6080008@yahoo.co.uk>,
 Mark Sparshatt <msparshatt@yahoo.co.uk> wrote:

> Foo wrote:
> 
> >Hi-
> >
> >I am new to ruby and I am reading the SAMS "Teach yourself Ruby in 21 
> >days" book.  I've gotten to the part where the book discusses the 
> >operating system and Ruby.  I'm having trouble with an example in the 
> >book and was hoping someone could help.  The script is spinnertest.rb:
> >
> >#!/usr/bin/env ruby
> >
> >require 'spinner2'  # Edit this line for different spinners
> >
> ># Our slow recursive Fibonacci function.
> >def fib(n) (n<=2) ? 1 : (fib(n-2)+fib(n-1)) end
> >
> >print "Please wait while I calculate a large Fibonacci number. "
> >
> >animation = Spinner.new
> >result = fib(28)
> >animation.stop
> >
> >puts
> >puts result
> >
> >
> >The class is called spinner2.rb:
> >
> >class Spinner
> >    Baton = '\|/-'
> >    def initilaize
> >  
> >
>               ^^^^^^
> this should be
>      def initialize
> 
> >        STDOUT.flush
> >        @child = IO.popen('-', 'w+')
> >        if @child.nil?
> >            rotation = 0
> >            until select([$stdin], nil, nil, 0.2)
> >                STDERR.printf "%c\b", Baton[(rotation+=1) &3]
> >            end
> >            gets #read the 'stop' message
> >            STDERR.printf " \b" # erase the last Baton character
> >            exit!
> >        end
> >    end
> >    
> >    def stop
> >        @child.puts("stop yer rotation") # message content is unimportant
> >        @child.close
> >    end
> >end
> >
> >When I run spinnertest.rb I get a blank screen for awhile, then after 
> >the calculation is complete I get the following:
> >
> >../spinner2.rb:18:in `stop': private method `puts' called for 
> >nil:NilClass (NoMethodError)
> >        from ./spinnertest.rb:12
> >Please wait while I calculate a large Fibonacci number. 
> >
> >I am guessing that ruby is having trouble with 'puts' being used this 
> >way, but I do not understand why, nor, how to fix it.  Can someone 
> >please help me with this item?
> >
> >:)Thanks.
> >
> >SA
> >
> >
> >  
> >