From: James Edward Gray II <james@...>
Date: 2005-09-07T06:31:36+09:00
Subject: Re: Beginner: Options with YAML

On Sep 6, 2005, at 1:51 PM, Oliver Cromm wrote:

> Well, by 'clumsy' I meant exactly something like
>
> |  login(Options['server'], Options['port'], Options['user'],  
> Options['pass'])
>
> and so on throughout the script.

Hmm, I don't see that as significantly different from:

     login(SERVER, PORT, USER, PASS)

Though I will concede that it's a little shorter.

I would probably pass some kind of options object into the method and  
query it from inside:

#!/usr/local/bin/ruby -w

require "ostruct"
require "yaml"

def open_connection( connection )
     p connection.server
end

if File.exists? "config.yaml"
     config = File.open("config.yaml") { |file| YAML.load(file) }

     open_connection(config)
else
     config = OpenStruct.new( :server => "news.example.org",
                              :port   => 100,
                              :user   => "myname",
                              :pass   => "topsecret" )

     File.open("config.yaml", "w") { |file| YAML.dump(config, file) }
end

__END__

Even better, perhaps a Connection object could manage its own data,  
and then you could just YAML it back and forth, or something similar.

> I don't know what reflection means in this context, but am I guessing
> right that we are talking about something (maybe something more  
> elegant)
> that has the same *effect* as:
>
> def getOptions
>   Options = YAML.load_file(OPTFILE)
>   SERVER = Options['server']
>   PORT = Options['port']
>   ...
> end

Here's what I basically had in mind:

#!/usr/local/bin/ruby -w

require "yaml"

$standard_constants = Module.constants

def save_config
     config = Hash.new
     (Module.constants - $standard_constants).each do |const|
         config[const] = Module.const_get(const)
     end

     File.open("config.yaml", "w") { |file| YAML.dump(config, file) }
end

def load_config
     config = File.open("config.yaml") { |file| YAML.load(file) }

     config.each_pair do |const, value|
         Object.const_set(const, value)
     end
end

if File.exists? "config.yaml"
     load_config
     p SERVER
else
     SERVER = "news.example.org"
     PORT   = 100
     USER   = "myname"
     PASS   = "topsecret"

     save_config
end

__END__

Hopefully this gives you some fresh ideas.

James Edward Gray II