Checking for a group?

lothcat

This seems like a silly question, but how do I check if something is a group? I simply can't figure it out.

The user will click to run a function, and I need to make sure that what they clicked on is a group so the function can run properly. I've looked through the API but it was as useless as ever.

TIG

xxx.class==Sketchup::Group [EDIT: corrected typo!]
returns true/ false
To find 'xxx' you have various options...
Depends how the user is to choose the object.
Preselected it's from
xxx=model.selection[0]
If picked with the mouse [within a tool] it's more complex... you make a pickhelper and check what is picked - http://code.google.com/apis/sketchup/docs/ourdoc/pickhelper.html
You then need to mess on with picked_element, best_picked, all_piked etc to see if there's a group in there as expected...

Dan Rathbun

@tig said:

xxx==class.Sketchup::Group
returns true/ false

He means:
xxx.class == Sketchup::Group
returns boolean

The class() method is a Core Ruby instance method, defined within class Object (the supremeclass of all classes,) and so is inherited by all classes, and their subclasses.

Make sure you have the CHM for the Core Ruby classes and methods:
RUBY PROGRAMMING REFERENCES - CHM format
or use the online reference:
Ruby Documentation 1.8.6 Core

TIG

Thanks Dan, another typo - more haste less speed...
I've fixed the original...

lothcat

Thanks!

artmusicstudio

hello,
i went thru all snippets,
but

how can i check, if a group @NAME
exists or not in the actve model.

situation

i create a group NAME by ruby
then it either is deleted or not

whith the next call ruby shall check, if group NAME is there

if not, create it
if so, delete and create it new

my trial:


entities = @NAME.entities 
entity1 = entities[1]        
status = entity1.valid?

unless status == true
   model = Sketchup.active_model
   @NAME.erase!
end

reports an not existing group, so no check is possible

tahnx for helping on this

stan

TIG

A simple

group.valid?

or - assuming the group is named 'xxx'

group=nil
Sketchup.active_model.definitions.each{|d|
next unless d.group?
if d.instances[0].name=="xxx"
group=d.instances[0]
break
end
}

or

group=nil
some_entities.grep(Sketchup::Group).each{|g|
if g.name=="xxx"
group=g
break
end
}

artmusicstudio

hi tig and yes,


@group_STAIR.erase! if @group_STAIR.valid?

works perfect.

another advantage: when i generate my group and copy it manually to the desired place
and then call the ruby again, the original is beeing deleted and the copy remains.
that is, what i wanted to achieve: when the user is satisfied with the result, he can either make a copy or make a component out of the group.
next step is done!
thanx a lot
stan

ps: (on the other hand i was not sure in example 2 and 3, why they did not work for me, i still investigate, must be the NAME definition, i think).

Dan Rathbun

In Ruby, only constants are ALL_UPPERCASE

artmusicstudio

hi dan, have to correct it ( was only for me to see it better while working on it), thanx. (and i already study the files, you recomend for newbie's...but it's a lot to learn, of course)

and i have to correct my previous statement:

my "checking" code does not work in a new opended file. it again reports a deleted group, while searching for it.

but, as soon as i create the first group and the activate the checking-line, it works.

so now a question:

is there a way to define 1 variable (true or false) ON LOAD ?
so this variable would only be "true" when sketchup is opened and before my ruby script runs for the first time (i could overwite it then for the active session)?
then i could run the checking code "unless onload == true " or something like that.

ragrds stan

TIG

How is your code 'encapsulated' ?
In a module or a class ?
In a module use an instance variable @onload=true within the module but outside of any methods will set it as true initially, as the code is first loaded as SketchUp starts up.
Later when you run you first method in that module @onload=false ...
The @onload value in remembered across instances of that code during that session of SketchUp.
For a class [Tool etc] you need a @@onload prefixed class variable to keep it enduring across uses of that class. Again define it initially outside of any class methods but inside the class's code.

When you finish processing and exit your method you can might want to reset @onload=true etc ? It depends on what it is used for etc...

Because the user could open a new or existing SKP, and that would continue to use your already-loaded/reset code you might want to construe an AppObserver that resets @onload=true whenever such things change ?

However, KISS - the simplest way to think about this is to test for group.valid? before trying to do anything to it. It's a basic trap in scripts to trap for anticipated possible failures:
do_something() if group.valid?
Another way to trap for unexpected failures is like this:
begin do_something() rescue do_something_different() end

Dan Rathbun

Also ...what we do is use the global methods defined in the file "sketchup.rb"

The two we use are named file_loaded() and file_loaded?()

require("sketchup.rb")

module AMS # <--<< your toplevel namespace

  module ThisPlugin  # <--<< rename this

    ### CONSTANTS
    #
    THISFILE = "#{Module.nesting[0]};#{File.basename(__FILE__)}"

    ### MODULE VARS
    #
    @@loaded = false unless defined?(@@loaded)

    ### PROXY CLASS (for this module)
    #
    class << self

      ### METHODS
      #
      def loaded?()
        @@loaded = file_loaded?( THISFILE )
      end

    end # proxy class


    ### define plugin specific classes or sub-modules here
    #
    class ThisTool
      ### define tool class callbacks here
    end


    ### FINAL RUN ONCE CODE
    #
    unless loaded?

      # set up dropdown menu here
      # and/or right-click popup menu

      # attach any initial observers here

      # mark this file as loaded
      file_loaded( THISFILE )

    end

  end # module ThisPlugin

end # module AMS

artmusicstudio

@ tig
hi tig, thanx,
with


def delete_model_zf
#***************************************************************************
@putswitch = 0 
	begin
	@group_stair.erase!
	rescue
	end
end

it worked, as soon as i understood, that rescue can also be NOTHING, so the code runs thru end the method ends

@ dan, thanx,
this is still higher programming syntax (for my brain), i tried to encapsulate in
require("sketchup.rb")
MODULE AMS
MODULE 01.rb // is it right to put hier 01.rb ??? (the work-name of the ruby)
MY CODE
END MODULE
END AMS,
but have errors. have to work it out! but i would like to put the ruby into a proper form for the first release / check. i'll get back to this later.

Dan Rathbun

module is a keyword, it must be all lowercase.

Module is a class name, it must be title case, if you refer to the class.

Dan Rathbun

@artmusicstudio said:

MODULE 01.rb // is it right to put hier 01.rb ??? (the work-name of the ruby)

No you cannot use a Numeric expression as a Class or Module name. They must begin with alpha characters, and be title case.