[Closed] SDK – applyable_class properties issue

Value* KeyValuePair::get_property(Value** arg_list, int count)
{
	if (arg_list[0] == n_key) return _key;			//where is n_key come from?
	return Value::get_property(arg_list, count);
} 

As far as I understood it, def_name(key); defines a Value* n_key.
This seems to be the way the samples work as well. Apart from that it doesn’t work at all for me :shrug:

Thanks. I’ve sent you a PM.

Well, after having read the topics in the Sparks archive kindly provided by Yannick, and having studied the problem for two more days, I’m still completely at a loss of what’s going on!
I have been looking at /howto/maxscript/testdlx but that didn’t clear things up at all. For one, it does not work when loading the plugin (missing LibClassDesc and LibNumberClasses).

I tried copying the code into my own plugin, and made it run. Now the curious thing is, in the List max class defined there, is a property “count”. In the implementation, there’s a function get_count and set_count, which are called when using the property in maxscript. I’ve verified this by setting a breakpoint in it, and it works as you’d expect.
Now, I added my own property in the exact same way, but the get_myprop and set_myprop are never called! When calling them from maxscript, it just runs the get_property and set_property function, which pass it on to the Value class.

Another thing I noticed: n_count is a valid pointer, defined somewhere in core. If I define my property in the same way (def_name(myprop)), I get a null pointer. This also goes for two properties defined by the howto, which as a result do not work.

So, I have two problems:

• Where do the calls to get_count and set_count come from? Why isn’t get_property and set_property called for the count property?
• How do I make my pointers created with the def_name macro valid pointers so I could use them in get_property?

:curious:

Can you post or send me the code ?

Well, in the testdlx I added the following:
dlxClass.h:

// line 45
def_property(count);
def_property(my_prop);

dlxClass.cpp

// line 20
def_name(head);
def_name(tail);
def_name(my_prop);

// and modified the get_property:
Value*
ListValue::get_property(Value** arg_list, int count)
{
Value* prop = arg_list[0];
	if (prop == n_my_prop)
		return &true_value; // just to see if it works.
	else if (prop == n_head)
		return head ? head : &undefined;
	else if (prop == n_tail)
		return head ? (Value*)tail : (Value*)&undefined;
	else
		return Value::get_property(arg_list, count);
}

I added the two functions to get the DLL to work (LibClassDesc and LibNumberClasses), but left the rest of the code exactly as it was.

I have it working!

This MAXScript SDK is a nightmare :twisted:.

I have successfully found how to initialize well the names defined:

Remove the "def_property(my_prop);" declaration in dlxClass.h

Remove the names declarations in dlxClass.cpp and create a file "namedefs.h" in the project that contains them:

namedefs.h

def_name (head)
    def_name (tail)
    def_name (myprop)

• tester.cpp

After the common includes:

Replace

tester.cpp

// define the new primitives using macros from SDK
    #include "definsfn.h"
    def_visible_primitive( my_copy_file,	"myCopyFile");
    def_visible_primitive( my_file_in,		"myFileIn");

By

tester.cpp

#ifdef ScripterExport
        #undef ScripterExport
    #endif
    #define ScripterExport __declspec( dllexport )
    
    // define the new primitives using macros from SDK
    #include "definsfn.h"
    def_visible_primitive( my_copy_file,	"myCopyFile");
    def_visible_primitive( my_file_in,		"myFileIn");
    
    #include "definsfn.h"
    #    include "namedefs.h"

tester.cpp

void tester_init()
    {
    	CharStream* out = thread_local(current_stdout);
    	out->puts(_T("--* Testdlx.dlx 4.00 loaded *--
"));
    	define_system_global("mySlider", get_slider_time, set_slider_time);
    	install_rollout_control(Name::intern("foo"), FooControl::create);
    
    #include "defimpfn.h"
    #	include "namedefs.h"
    }

• dlxClass.cpp

After the common includes:

Replace

dlxClass.cpp

#include "lclinsfn.h"
    #	include "listpro.h"
    #	include "setpro.h"

By

dlxClass.cpp

#ifdef ScripterExport
        #undef ScripterExport
    #endif
    #define ScripterExport __declspec( dllexport )
    
    #include "lclinsfn.h"
    #	include "listpro.h"
    #	include "setpro.h"
    
    #include "defextfn.h"
    #    include "namedefs.h"

get_property() function should work fine now!
Good luck :). If you want, I can send you the code.


The topic "How do I make properties and methods of a class?" in sparks archive helped me a lot (see Larry Minton's posts, he's the MAXScript developer).

If you could send the code, that would be amazing!

And I’m glad to see that I’m not the only one who finds this part of the SDK utterly confusing.

I’ve got it working now too, thanks Yannick!
However, I really do not understand why it is working. The names defined seem to magically point at the proper value or class now, and that made obviously makes the get_property function work correctly. The count getter and setters are still not going through the get_property function though, for reasons completely beyond my understanding.

It’s quite a mysterious bit of design this maxscript SDK…