Reimplement module functions

Instead of a lambda, create a new type containing all data required to
call the function, and support it in the evaluator.  Because this type
now also needs to store the function documentation, it is too big for
Lisp_Misc; use a pseudovector instead.  That also has the nice benefit
that we don't have to add special support to the garbage collector.

Since the new type is user-visible, give it a predicate.

Now we can easily support 'help-function-args' and 'func-arity'; add
unit tests for these.

* src/lisp.h (allocate_module_function, MODULE_FUNCTIONP)
(XMODULE_FUNCTION): New pseudovector type 'module function'.

* src/eval.c (FUNCTIONP): Also treat module functions as functions.
(funcall_lambda, Ffuncall, eval_sub): Add support for calling module
functions.
(Ffunc_arity): Add support for detecting the arity of module
functions.

* src/emacs-module.c (module_make_function): Adapt to new structure.
Return module function object directly instead of wrapping it in a
lambda; remove FIXME.
(funcall_module): New function to call module functions.  Replaces
`internal--module-call' and is called directly from eval.c.
(syms_of_module): Remove internal helper function, which is no longer
needed.
(module_function_arity): New helper function.

* src/data.c (Ftype_of): Adapt to new implementation.
(Fmodule_function_p, syms_of_data): New user-visible function.  Now
that module functions are first-class objects, they deserve a
predicate.  Define it even if not compiled with --enable-modules so
that Lisp code doesn't have to check for the function's existence.

* src/doc.c (Fdocumentation): Support module functions.

* src/print.c (print_object): Adapt to new implementation.

* src/alloc.c (mark_object): Specialized garbage collector support is
no longer needed.

* lisp/help.el (help-function-arglist): Support module functions.
While there, simplify the arity calculation by using `func-arity',
which does the right thing for all kinds of functions.

* test/data/emacs-module/mod-test.c: Amend docstring so we can test
the argument list.

* test/src/emacs-module-tests.el (mod-test-sum-docstring): Adapt to
new docstring.
(mod-test-non-local-exit-signal-test): Because `internal--module-call'
is gone, the backtrace has changed and no longer leaks the
implementation.
(module--func-arity): New test for `func-arity'.
(module--help-function-arglist): New test for `help-function-arglist'.

1 files changed, 13 insertions, 4 deletions

diff --git a/src/eval.c b/src/eval.c
index 98d25cc4fed..f472efad52e 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2261,7 +2261,7 @@ eval_sub (Lisp_Object form)
             }
         }
     }
-  else if (COMPILEDP (fun))
+  else if (COMPILEDP (fun) || MODULE_FUNCTIONP (fun))
     return apply_lambda (fun, original_args, count);
   else
     {
@@ -2687,7 +2687,7 @@ FUNCTIONP (Lisp_Object object)
 
   if (SUBRP (object))
     return XSUBR (object)->max_args != UNEVALLED;
-  else if (COMPILEDP (object))
+  else if (COMPILEDP (object) || MODULE_FUNCTIONP (object))
     return true;
   else if (CONSP (object))
     {
@@ -2742,7 +2742,7 @@ usage: (funcall FUNCTION &rest ARGUMENTS)  */)
 
   if (SUBRP (fun))
     val = funcall_subr (XSUBR (fun), numargs, args + 1);
-  else if (COMPILEDP (fun))
+  else if (COMPILEDP (fun) || MODULE_FUNCTIONP (fun))
     val = funcall_lambda (fun, numargs, args + 1);
   else
     {
@@ -2892,7 +2892,8 @@ apply_lambda (Lisp_Object fun, Lisp_Object args, ptrdiff_t count)
 
 /* Apply a Lisp function FUN to the NARGS evaluated arguments in ARG_VECTOR
    and return the result of evaluation.
-   FUN must be either a lambda-expression or a compiled-code object.  */
+   FUN must be either a lambda-expression, a compiled-code object,
+   or a module function.  */
 
 static Lisp_Object
 funcall_lambda (Lisp_Object fun, ptrdiff_t nargs,
@@ -2949,6 +2950,10 @@ funcall_lambda (Lisp_Object fun, ptrdiff_t nargs,
         }
       lexenv = Qnil;
     }
+#ifdef HAVE_MODULES
+  else if (MODULE_FUNCTIONP (fun))
+    return funcall_module (XMODULE_FUNCTION (fun), nargs, arg_vector);
+#endif
   else
     emacs_abort ();
 
@@ -3060,6 +3065,10 @@ function with `&rest' args, or `unevalled' for a special form.  */)
     result = Fsubr_arity (function);
   else if (COMPILEDP (function))
     result = lambda_arity (function);
+#ifdef HAVE_MODULES
+  else if (MODULE_FUNCTIONP (function))
+    result = module_function_arity (XMODULE_FUNCTION (function));
+#endif
   else
     {
       if (NILP (function))