Namespace question on noob level

liquid98

Hello everybody,

I have a script that contains several methods that are useful in other scripts. I called it shared.rb.

It's contents:


require 'sketchup.rb'

module AA

	def self.usefull1
		# code here
	end

	def self.usefull2
		# code here
	end

	def self.usefull3
		# code here
	end

end

So I can use the methods in other files like this:

` require 'sketchup.rb'
require 'shared.rb'

...
AA.usefull1`

My question: is there a possibility to avoid prefixing the Module name?
Like:
` require 'sketchup.rb'
require 'shared.rb'

...
usefull1`

Tnx, liquid

sdmitch

No because it is in a module. You could only do that if you removed the module wrapper which is not recomended due to potential conflects with other scripts.

liquid98

Hi Mitch,

Thanx for your answer!

Dan Rathbun

@liquid98 said:

My question: is there a possibility to avoid prefixing the Module name?
Like:
` require 'sketchup.rb'
require 'shared.rb'

...
usefull1`

Actually yes there is as long as you are always coding within some namespace. (Never create global methods.)

1) First of all, your library module needs to be INSIDE your toplevel "Author" module.
2) You need to make the module a double-duty Library/Mixin module, using the module_function method.

file: "liquid/useful.rb":


require 'sketchup.rb'

module Liquid
  module Useful

    module_function

    def usefull1
      # code here
    end

    def usefull2
      # code here
    end

    def usefull3
      # code here
    end

  end # Useful
end # Liquid

Then in another file:


require 'sketchup.rb'

module Liquid
  module FancyPlugin

    require("liquid/useful.rb")
    include(Liquid;;Useful)

    puts( usefull1 ) if useful2

    # more code

  end # FancyPlugin
end # Liquid

But never include() modules into the TOPLEVEL_BINDING, which is Object.

Dan Rathbun

@liquid98 said:

The require("liquid/useful.rb") line is mandatory inside the two modules 'Liquid' and 'FancyPlugin' ??

NO

@liquid98 said:

Or is it also possible to put it among the first lines of the script?

YES

@liquid98 said:

What do you mean by

'But never include() modules into the TOPLEVEL_BINDING, which is Object. ? '

Unwrapped methods are evaluated in Object, and become global methods. They get inherited by EVERYONE's modules and classes, and make us angry.
The same for constants, instance variables and class variables.

Just plain code within your own namespace, and we will love you.

Dan Rathbun

@liquid98 said:

So every script should be in a double namespace ?? (Liquid and Name).. with or without loading other scripts ??

All your code needs to be within YOUR namespace (whatever you decide to call it.)

You will find that you wish to separate each of your plugins from one another. So each goes in it's own sub-module namespace, so they do not clash with each other.

Also in the "Plugins" directory.. your files need to go in YOUR "author" sub-directory.
You will want to maintain your plugins separately, so each should go in a sub-dir of your "author" directory.

I suggest having the directory names and modules the same. It helps syncing up the require arguments with the include or extend arguments.

liquid98

Cooool! Thanx, I was hoping for this!

Global methods: just methods without any namespace? -- Refrain from using them, right?

So every script should be in a double namespace ?? (Liquid and Name).. with or without loading other scripts ??

What do you mean by:

'But never include() modules into the TOPLEVEL_BINDING, which is Object. ? '

EDIT:
require("liquid/useful.rb") include(Liquid::Useful)
Should be placed outside the modules!!

Thnx

liquid98

Thanx again Dan,

Really beautiful to see it running this way!!
This trick is not widely known according to my grep..

Liquid

liquid98

Hi Dan,

Thnx for the information. The next script I've written will have this namespace treatment!
By the way I found that calling :

require("liquid/useful.rb")
include(Liquid;;Useful)

only works outside the module definition..

edit: Other question: Is there some evil in using load instead of require?

Dan Rathbun

@liquid98 said:

By the way I found that calling :

require("liquid/useful.rb")
> include(Liquid;;Useful)

only works outside the module definition..

NO.. This is not true, .. and Do not do this. If you do, you will add methods to EVERYONE's modules and classes, not just yours.

If you cannot get it to work, then you are doing something incorrect.

FYI: The mixin methods, in a mixin module, must be defined as instance methods, without a self. before the name.

Dan Rathbun

[off:2wuy0iss]
@liquid98 said:

Other question: Is there some evil in using load instead of require?

They do different things:

require() checks the $LOADED_FEATURES (aka $",) array and only loads the file if it has not already been loaded, and if it does (without error since v1.8.4, or so,) adds the filepath to that array. (Beware that v1.8.0 adds the filepath before the load attempt, so under Windows Sketchup < 8.x, that is still running v1.8.0, filepaths for failed files will exist in $".)

load() does not check $", always attempts to load the file, even it it was previously loaded, and does not push any filepaths into the $" array.

So.. we use load() during debugging, to re-load scripts, which will re-define methods with the new changes.

After release... require() is used so libraries are only loaded once.[/off:2wuy0iss]

Dan Rathbun

@liquid98 said:

This trick is not widely known according to my grep..

I will need to disagree. It is not a "trick."

Mixin Library Modules, that are used with include() and extend(), is basic Ruby (perhaps in the second semester course,) but still one of the fundamental principals of the dynamic nature built into Ruby.

The problem is that most people are impatient, and refuse to read the Ruby textbook, to learn the fundamentals first. They read the first chapter and start hacking away.

My Question to YOU: Have YOU read the book yet ??
(I do not think you have given your questions.)

It is in the "doc" folder of the the Full Ruby install, usually on Windows:
%(#004000)["C:/Ruby186/doc/ProgrammingRuby.chm"]

Also online at:
http://phrogz.net/ProgrammingRuby/frameset.html

Am I the only person in the world, who read this book cover-to-cover, before ever writing a single line of Ruby ??

Doing so saved me much frustration ! Although that book is old (... written in the v1.6.x days,) it is still valid, and I still refer to it often.

liquid98

Dan,

No I haven't read the book yet. Though I scraped my information from several places, like this forum, google, other books, Rubydocs
'Automatic Sketchup', etc.

In my point of view 90% of ruby scripting for sketchup is just using the Ruby API. The other 10 % is a set of rules cq best practices
to manage the code in a efficient way.

Though I thank you for your suggestion, I have I complete folder of URL's with ruby books, to impressive to start with..
So a good starting point is welcome.

Rene

liquid98

@dan rathbun said:

@liquid98 said:

By the way I found that calling :

require("liquid/useful.rb")
> > include(Liquid;;Useful)

only works outside the module definition..

NO.. This is not true, .. and Do not do this. If you do, you will add methods to EVERYONE's modules and classes, not just yours.

If you cannot get it to work, then you are doing something incorrect.

FYI: The mixin methods, in a mixin module, must be defined as instance methods, without a self. before the name.

Hi Dan,

I just copy pasted your example into two files:
It works only if

require("useful.rb")
include(Liquid;;Useful)

is outside the modules.
Can you please take a look??

Thnx,

Rene

mixin test

Dan Rathbun

Ok got it.. you need to use a proxy class inside a module:

(1) The word useful has only 1 "L", by the way.

"Plugins/liquid/useful.rb"

  module Liquid

    MENU = UI.menu('Plugins').add_submenu('Liquid')

    module Useful

      module_function

      def useful_1()
        msg = "I am method useful_1()."
        puts( msg )
        return msg
      end

      def useful_2()
        msg = "I am method useful_1()."
        puts( msg )
        return msg
      end

      def useful_3()
        msg = "I am method useful_1()."
        puts( msg )
        return msg
      end

    end # Useful
  end # Liquid

"Plugins/liquid/fancy.rb"

  require("liquid/useful.rb")

  module Liquid

    module Fancy
    
      class << self # proxy class

        include(Liquid;;Useful)

      end # proxy class

      useful_1()

    end # module Fancy

  end # module Liquid

But for a custom class, no proxy class is needed:
"Plugins/liquid/fancytool.rb"

  require("sketchup.rb")
  require("liquid/useful.rb")

  module Liquid

    module Fancy
    
      class FancyTool

        include(Liquid;;Useful)

        def activate()
          UI.messagebox( useful_1() )
          Sketchup.active_model.select_tool(nil)
        end

      end # class

      unless file_loaded?('Liquid;;Fancy;;FancyTool')
        @@tool = FancyTool.new()
        Liquid;;MENU.add_item('FancyTool') { 
          Sketchup.active_model.select_tool(@@tool)
        }
        file_loaded('Liquid;;Fancy;;FancyTool')
      end # unless

    end # module Fancy

  end # module Liquid

liquid98

Off topic:

@unknownuser said:

(1) The word useful has only 1 "L", by the way.

thanx for your correction, the English language is not my mother language as you might have noticed..
/Off topic

All code is safe now and my code works like a charm, so thanx for your help. And yes I SHALL read the book before
I come here and ask questions like this..