Simple Extension for Mac

Dan Rathbun

I've been playing around with C Extension recently and I would like to know how if there is an equivalent of is_a? ruby function in C level.

If you have the CHM... you can click on the method description, and the C source will popup:
(Also works for online version, but the source link must be clicked directly, and is only visible when the mouse is hovering over the method description.)

Dan Rathbun

So it looks like there are some macros defined in C, to make life easier ... CLASS_OF(), RCLASS_SUPER(), etc.

Dan Rathbun

Pragmatic Programmer: Extending Ruby 1.9

olilej

Great, my goal is to make sure I'm dealing with a Entity in order to access its attributes.

Here is the code I've come up with.

VALUE result = rb_obj_is_kind_of(obj, rb_path2class("Sketchup;;Entity"));
if (Qtrue == result){
	VALUE rval = rb_funcall(obj, rb_intern("get_attribute"), 2, rb_str_new2("dynamic_attributes"), rb_str_new2("..."));
	...
}

Dan Rathbun

Only Sketchup::ComponentDefinition and Sketchup::ComponentInstance will have dictionaries with that special name.