From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2010-06-02T23:46:48+09:00
Subject: Re: having a class method called only one time ?

2010/6/2 Une Bévue <unbewusst.sein@google.com.invalid>:
> Une Bévue <unbewusst.sein@google.com.invalid> wrote:
>
>> Array HOST_IP = [] # the array let me make the constant "mutable"
>
> it seems to work like that :
>
> class HFSFile
>
>  HOST_IP = []
>
>  ...
>
>  def host_ip
>    return HOST_IP.first unless HOST_IP.empty?
>    HOST_IP << host_ip_get
>    return @h[:host_ip]
>  end
>
>  ...
>
>  private
>
>  def host_ip_get
>    $stderr.puts "'host_ip_get' was called!" # called 1 time for 2
> instantiations.
>    @h[:host_ip] = ''
>    while @h[:host_ip].empty?
>      @h[:host_ip] = `curl -s http://whatismyip.org`.chomp
>    end
>    return @h[:host_ip]
>  end
>
>  ...
>
> end
> --

I think it looks cleaner using the idiom Tony described:

 class HFSFile
  def host_ip
    @host_ip ||= host_ip_get
  end
  private

  def host_ip_get
    $stderr.puts "'host_ip_get' was called!" # called 1 time for 2
instantiations.
    host_ip = ''
    while host_ip.empty?
      host_ip = `curl -s http://whatismyip.org`.chomp
    end
    host_ip
  end
 end

Jesus.