> On Jul 14, 2021, at 7:48 PM, Yuan Fu <casouri@gmail.com> wrote:
> 
>>> 
>>> And how do I use a USER_PTR? Do I cast it into (struct Lisp_User_Ptr) and
>>> use it normally, or is there some helper function that I should use?
>> 
>> Most likely you'll want some of your functions to take objects that
>> should be "tree sitter parsers", but you'll only receive a Lisp_Object
>> so you'll need to be able to *test* that the object you received is
>> indeed a "tree sitter parser".
>> 
>> For that reason you'll probably want to add a new entry to `pvec_type`
>> rather than use a USER_PTR.
> 
> 
> Actually, what is the correct way to provide a pointer from a dynamic module to Emacs core? I tried to use USER_PTR, but the dynamic module can only return an emacs_value, and to convert an emacs_value to a Lisp_Object, I need to use value_to_lisp, which is not exposed by emacs-module.c.
> 
> I want to provide individual tree-sitter language definitions from dynamic modules so that one don’t need to compile Emacs with language definitions.

I just realized that I can regard emacs_value just as Lisp_Object. Is that right?

Yuan