Prototype design pattern

ruby-talk
1

Hm, it's not at
http://wiki.rubygarden.org/Ruby/page/show/ExampleDesignPatternsInRuby

Anyway, it looks to me like some combination of .clone plus a factory.
I'm not sure there's any real savings in Ruby to doing things this way,
but I'd be happy to be proved wrong.

Regards,

Dan

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···

-----Original Message-----
From: ara.t.howard@noaa.gov [mailto:ara.t.howard@noaa.gov]
Sent: Wednesday, July 12, 2006 8:27 AM
To: ruby-talk ML
Subject: prototype design pattern

anyone know of a good impl for ruby?

regards.

-a

2

Hm, it's not at
http://wiki.rubygarden.org/Ruby/page/show/ExampleDesignPatternsInRuby

Anyway, it looks to me like some combination of .clone plus a factory. I'm
not sure there's any real savings in Ruby to doing things this way, but I'd
be happy to be proved wrong.

hi daniel-

savings is only keystrokes. but it can very elegant looking and, these days,
ruby coding bores me unless it looks good too - solving problems is just too
easy in it to provide enough challenge! :wink: take this code for example:

     fortytwo :~/eg/ruby/prototype > cat a.rb
     require 'prototype'

     singleton = Prototype.new{
       @a, @b = 40, 2

       def answer() @a + @b end
     }

     p singleton.answer

     fortytwo :~/eg/ruby/prototype > ruby a.rb
     42

     fortytwo :~/eg/ruby/prototype > cat b.rb
     require 'prototype'

     DB = Prototype.new{
       host 'localhost'
       port 4242

       def connect() 'do something' end

       def inspect() [host, port].join ':' end
     }

     p DB
     p DB.host
     p DB.port

     fortytwo :~/eg/ruby/prototype > ruby b.rb
     localhost:4242
     "localhost"
     4242

do you like the look of it?

i'll post my impl in a follow-up.

cheers.

-a

···

On Wed, 12 Jul 2006, Berger, Daniel wrote:
--
suffering increases your inner strength. also, the wishing for suffering
makes the suffering disappear.
- h.h. the 14th dali lama

3

Why no go the extra step?

     DB = Prototype.new{
       host 'localhost'
       port 4242

       connect does{ 'do something' }

       inspect does{ [host, port].join ':' }
     }

T.

···

ara.t.howard@noaa.gov wrote:

     DB = Prototype.new{
       host 'localhost'
       port 4242

       def connect() 'do something' end

       def inspect() [host, port].join ':' end
     }

4

easy enough, i'd simply make does() return a block extended with a marker:

   def does &b
     class << b
       def does() true end
     end
     b
   end

then, later

   if b.respond_to? 'does'
     # defined a method
   else
     # attribute with proc value
   end

otherwise i could tell the difference between

   foobar lambda{ 'plain ol block' }

   foobar does{ 'method body' }

in any case, i'm unclear as to what

   connect does{ 'do something' }

buys you over

   def connect() 'do something' end

other than two chars. i admit it looks nice though... actually i guess the
closure might make it nice since you could do

   a = 42

   connect does{ p a }

which you cannot with a normal method def. so - what's __your__ reasoning on
this?

cheers.

-a

···

On Thu, 13 Jul 2006 transfire@gmail.com wrote:

Why no go the extra step?

    DB = Prototype.new{
      host 'localhost'
      port 4242

      connect does{ 'do something' }

      inspect does{ [host, port].join ':' }
    }

T.

--
suffering increases your inner strength. also, the wishing for suffering
makes the suffering disappear.
- h.h. the 14th dali lama

5

transfire@gmail.com writes:

     DB = Prototype.new{
       host 'localhost'
       port 4242

       def connect() 'do something' end

       def inspect() [host, port].join ':' end
     }

Why no go the extra step?

     DB = Prototype.new{
       host 'localhost'
       port 4242

       connect does{ 'do something' }

       inspect does{ [host, port].join ':' }
     }

Why not even this:

        connect { 'do something' }

        inspect { [host, port].join ':' }

···

ara.t.howard@noaa.gov wrote:
  
T.

--
Christian Neukirchen <chneukirchen@gmail.com> http://chneukirchen.org

6

sold.

jib:~/eg/ruby/prototype/prototype-0.2.0 > cat a.rb

require 'prototype'

prototype{ connect { p 'connect' } }.connect

jib:~/eg/ruby/prototype/prototype-0.2.0 > ruby -Ilib a.rb

"connect"

-a

···

On Fri, 14 Jul 2006, Christian Neukirchen wrote:

Why not even this:

       connect { 'do something' }

       inspect { [host, port].join ':' }

--
suffering increases your inner strength. also, the wishing for suffering
makes the suffering disappear.
- h.h. the 14th dali lama

7

Christian Neukirchen wrote:

Why not even this:

        connect { 'do something' }

        inspect { [host, port].join ':' }

Sweet and fine! My, oh my, it's looking like a paradigm.

T.