Seanohalpin doodle

Comments and changes to this ticket

• 

  Sean O'Halpin October 11th, 2009 @ 02:53 AM

  • State changed from “new” to “resolved”

  As you have pointed out, #instance_variable_defined? and #remove_instance_variable do exactly what you want.

  However, using them does rely on the underlying implementation of doodle, so I take your point. I really don't like the 'attribute query' methods of ActiveRecord (e.g. foo.name?) - IMHO they just add to the namespace clutter so I prefer two methods that take arguments over creating two more new methods per attribute.

  Doodle already has #assigned?(name). I have just added #clear!(name), so that will be in the next release (real soon now). For example:

  class Foo < Doodle
    has :name
  end
  foo = Foo("Jim")
  foo.assigned?(:name) # => true
  foo.clear!(:name)
  foo.assigned?(:name) # => false
  

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  Justin Ossevoort October 12th, 2009 @ 08:00 AM

  The clearer is great, that really complements the <.assigned?>

  I agree that the ActiveRecord way is ugly for it really conflicts with the way you'd expect boolean attributes to behave.
  I was thinking more along the lines of:

  class Foo < Doodle
    has :foo, :default => 'bar'
  end
  
  foo = Foo.new
  foo.assigned?(:name) # => false
  foo.has?(:name)      # => true
  
  foo.foo = 'foobar'
  foo.assigned?(:name) # => true
  foo.has?(:name)      # => true
  

  Where <.has?> nicely mirrors the declarative form of Doodle.

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  Justin Ossevoort October 12th, 2009 @ 08:49 AM

  • Tag set to “feature”
• 

  Sean O'Halpin October 15th, 2009 @ 12:28 PM

  I like #has?

  obj.has?(name) would be syntactic sugar for
  obj.doodle.attributes.key?(name) where obj can be either a class or an
  instance.

  I'll include this in the next release (so we'll have #has?, #assigned?
  and #clear!).

  While we're at it, can you think of any other reflections that should
  be exposed at the class or instance level?

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  Justin Ossevoort October 21st, 2009 @ 01:29 PM

  I've been mulling over this for some days, but for these cover the really essential introspection needs. The only possibly relevant one that's possibly missing is whether or not something has a default value.

  For this example I use valued? as the property, but I haven't given much thought for a name:

      require 'doodle'
  
      class Foo
          has simple_attr
  
          has default_attr do
              default{ 'bar' }
          end
  
          has init_attr do
              init{ 'bar' }
          end
      end
  
      f = Foo.new
  
      f.has?(:simple_attr)       # => true
      f.valued?(:init_attr)      # => false
      f.assigned?(:init_attr)    # => false
  
      f.has?(:default_attr)      # => true
      f.valued?(:default_attr)   # => true
      f.assigned?(:default_attr) # => false
  
      f.has?(:init_attr)         # => true
      f.valued?(:init_attr)      # => true
      f.assigned?(:init_attr)    # => true
  

  The biggest problem with this one is that I haven't come up with a clear scenario for this information (though it clearly conveys information).

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  Justin Ossevoort October 21st, 2009 @ 01:34 PM

  oh and the first block should of course have read:

      f.has?(:simple_attr)       # => true
      f.valued?(:simple_attr)    # => false
      f.assigned?(:simple_attr)  # => false
  

  Clear case of copy/past bug ;-)