DSL question

ruby-talk
1

Hi,

require 'traits'
$applications = {}

class Application
  has %w{ application_id title executable options}
end

def application(application_id, &block)
  a = Application.new
  ###### What goes here? #############
  $applications[application_id] = a
end

application :joe_app do
  title "Joe's Application"
  executable "My executable"
  options "my options"
end

application :another_app do
  title "Another App"
  executable "another exec"
  options "the options"
end

It should be pretty apparent to what I'm trying to do. Any ideas?
Can I restructure this better somehow?

Thanks,
Joe

2

Joe Van Dyk wrote:

Hi,

require 'traits'
$applications = {}

class Application
  has %w{ application_id title executable options}
end

def application(application_id, &block)
  a = Application.new
  ###### What goes here? #############
  $applications[application_id] = a
end

application :joe_app do
  title "Joe's Application"
  executable "My executable"
  options "my options"
end

application :another_app do
  title "Another App"
  executable "another exec"
  options "the options"
end

It should be pretty apparent to what I'm trying to do. Any ideas? Can I restructure this better somehow?

instance_eval can help:

class Application
   def title(*args)
     case args.size
     when 1
       @title = args[0]
     when 0
       @title
     end
   end

   def initialize(&block)
     instance_eval(&block)
   end
end

a = Application.new do
   title "Foo"
end

puts a.title # ==> Foo

3

Ooh, thanks. I forgot about that one. Revised code:

joe@ubuntu:~ $ cat test.rb
require 'traits'
$applications = {}

class Application
    has %w{ application_id title executable options }
end

def application(application_id, &block)
    a = Application.new
    a.instance_eval(&block)
    $applications[application_id] = a
end

application :joe_app do
    title "Joe's Application"
    executable "My executable"
    options "my options"
end

application :another_app do
    title "Another App"
    executable "another exec"
    options "the options"
end

puts $applications[:joe_app].title

joe@ubuntu:~ $ ruby test.rb
Joe's Application

···

On 6/25/05, Joel VanderWerf <vjoel@path.berkeley.edu> wrote:

Joe Van Dyk wrote:
> Hi,
>
> require 'traits'
> $applications = {}
>
> class Application
> has %w{ application_id title executable options}
> end
>
> def application(application_id, &block)
> a = Application.new
> ###### What goes here? #############
> $applications[application_id] = a
> end
>
> application :joe_app do
> title "Joe's Application"
> executable "My executable"
> options "my options"
> end
>
> application :another_app do
> title "Another App"
> executable "another exec"
> options "the options"
> end
>
>
> It should be pretty apparent to what I'm trying to do. Any ideas?
> Can I restructure this better somehow?

instance_eval can help: