Re: Tree-sitter api

[Eli Zaretskii]

> From: Yuan Fu <casouri@gmail.com>
> Date: Sat, 11 Sep 2021 13:29:09 -0700
> Cc: Tuấn-Anh Nguyễn <ubolonton@gmail.com>,
>  Theodor Thornhill <theo@thornhill.no>,
>  Clément Pit-Claudel <cpitclaudel@gmail.com>,
>  Emacs developers <emacs-devel@gnu.org>,
>  Stefan Monnier <monnier@iro.umontreal.ca>,
>  stephen_leake@stephe-leake.org
> 
> > But the <lang> part is still needed to be concocted somehow.  E.g.,
> > the conversion from "C#" to "c-sharp" isn't trivial.
> 
> The project name of tree-sitter’s C# definition is “tree-sitter-c-sharp”[1]. 
> So if someone wants to use the C# language, they probably know what symbol 
> represents it (we will explain the translation rule in doc-string and the 
> manual). I also want to point out that we don’t come up with the symbols 
> representing each language, the _user_ passes 'tree-sitter-parser-create' a 
> symbol representing a language, and we translate that symbol to dynamic 
> library name and C symbol name.

Surely, you don't mean "user" as in "the person who edits a source
file"?  I presume you mean the Lisp program, not the human user.  That
Lisp program is the major mode which wants to use TS services, and the
only thing that it has in hand is its own symbol, like 'c-mode' or
'python-mode' or 'f90-mode'.  It needs a way to pass the corresponding
TS module name to TS, and my question is: how would the major mode
compute the correct module name?  We need either a mode-specific
variable with that name, or some global function that could be used by
any major mode to obtain the language module name.

> >>> BTW, since dynamic libraries has different extensions on different 
> >>> systems, what I want to do it to try loading the library with .so, then 
> >>> try .dylib, then try .dll, is that a good idea?
> >> 
> >> We can do better, see load-suffixes.
> > 
> > And in C, you can use MODULES_SUFFIX directly.  Though we will
> > probably need some minor changes there, to have the suffix defined
> > even in a build --without-modules.
> 
> I’m using tree-sitter-load-suffixes with default value ‘(“.so”, “.dylib”, 
> “.dll”). Should I populate this variable with MODULES_SUFFIX and 
> MODULES_SECONDARY_SUFFIX, or should I just use the two SUFFIX in C? I.e., do 
> you see a need for users to customize suffixes?

I'd prefer a general variable shared-library-suffix(es), either a
single value specific to the target system or an alist with keys being
system names (from system-type).  Then we could use that in
load-suffixes (instead of MODULES_SUFFIX) and everywhere else.