$ versus @

[Jim]

@unknownuser said:

• replace all arrow codes with constants - e.g. $leftarrow -> LEFTARROW
• replace rest of globals with class variables - e.g. $value -> @@value

tested and it works (retains distance between calls of tool)

So, should we be creating new instances of a Tool each time, or referencing the already existing instance? (Instance level variables will also continue to exists for the life of the session, if you don't instantiate a new class every time the tool is activated.)

[AdamB]

I'd suggest always re-instance a Tool unless there is a compelling reason to make it persist.

As a general rule, releasing resources as soon as possible is a GoodThing, and secondly - and probably more importantly in a Ruby context, to ensure you don't carry references to Ruby objects and therefore stop garbage collection happening - worse still carry stale references to objects that have subsequently been deleted which tends to make SU jump into the azure blue sea of unallocated heap store and commit hare-kiri.

Adam

[tomot]

@didier bur said:

Hi,
But it is a lazy way of retaining values for your dialog boxes for instance, so user get the last values used.
One can avoid globals when using classes and methods, classes variables (@@) and objects variables (@).

I'm sorry but I cant let this topic die just yet. I have carefully reread all the
comments. Does this quote offer a solution to retaining values in Dialog Boxes?

[TIG]

For a dialog's default values that you want keeping from session to session within a particular model, I write them as attributes to the model itself: when the dialog initialises it looks for their values, if they are not there it takes defaults - otherwise you have them saved on a model by model basis... For an example see my TextTag.rb.

.

[RickW]

So, there you have it - three solutions that avoid globals:

1. Sketchup.read_default and Sketchup.write_default (persistent across SketchUp sessions and models)
2. Attributes (persistent within a given model, between sessions)
3. Class variables (@@variable) (persistent only within a SketchUp session)

[todd burch]

For persistent data for Dialog Boxes, you should use Sketchup.write_default and Sketchup.read_default. The keys and values are stored in the registry (Windows) and the plist (Mac).

Todd

[tomot]

@rickw said:

So, there you have it - three solutions that avoid globals:

1. Sketchup.read_default and Sketchup.write_default (persistent across SketchUp sessions and models)
2. Attributes (persistent within a given model, between sessions)
3. Class variables (@@variable) (persistent only within a SketchUp session)

Thanks everyone; I took a quick look at TIG's, TextTag.rb. It appears to take a little bit more understanding of Ruby then just simply banging out a mass replacement of @ to $ or vise versa. Nevertheless I will try to implement
these attributes on an exisitng Ruby of mine.

[Matt666]

Hi all !

Just one question : How can you do when you have that :

class ToolsObsTest < Sketchup;;ToolsObserver
	def onActiveToolChanged (tools_object, toolname, toolid)
		[b]@t[/b] = toolid
	end
end

and this variable @t is used here :

module
  def
    [b]@t[/b]
  end
end

So the variable is not used inside the first class section, but inside the instance of a module section ???
To find variable, I use $....

How can I preserve variable value ????

[AdamB]

Just define your Observer class in the scope of your Module

module Foo

class ToolsObsTest < Sketchup;;ToolsObserver
   def onActiveToolChanged (tools_object, toolname, toolid)
      @t = toolid
   end
end

end

instance = Foo;;ToolsObsTest.new

[Matt666]

Hi AdamB !
Thak you for your answer...

I tried it but it didn't work for me... @toolID (variable name in the code) always returns nil....
here is the real "tree" of the code (including your advice)

module Toto
	class ToolsObsTest < Sketchup;;ToolsObserver
		def onActiveToolChanged (tools_object, toolname, toolid)
			@toolID = toolid
		end
	end
	###
	def self.act
		model.tools.add_observer(Toto;;ToolsObsTest.new)
	end
	###
	def self.obs(id)
		@toolID
	end
end

---

Do you know why your method doesn't work ?
Thank you !

[fredo6]

Matt,

The two @toolid are different. One is a Class instance variable, the other a Module variable.
If you want to track the toolid in module Toto, then use a method to set its value, which you can call from the class.
Note that normally, you might use a Module variable, with @@, (since module instance variables do not really have real application)

def Toto.set_toolid(toolid)
   @@toolid = toolid
end
def Toto.get_toolid()
   @@toolid
end

Fredo

[Matt666]

Hello Fredo6 !
Thank you for your answer ! It works great ! get_toolid & set_toolid are perfect !
Just one thing, @@variable doesn't work. Just @variable...

Thank you Fredo !