OClosure: New function `function-documentation`

As mentioned in the original OClosure commit, OClosures (ab)use the
bytecode's docstring slot to hold the OClosure's type.  This currently
prevents OClosures from having their own docstring.

Introduce a new generic function `function-documentation` to fetch the
docstring of a function, which can then be implemented in various
different ways depending on the OClosure's type.

* lisp/simple.el (function-documentation): New generic function.
(bad-package-check): Strength-reduce `eval` to `symbol-value`.
* src/doc.c (Fdocumentation): Use it.

* lisp/emacs-lisp/oclosure.el (oclosure--accessor-docstring): New function.
* test/lisp/emacs-lisp/oclosure-tests.el (oclosure-test):
Add test for accessor's docstrings.

1 files changed, 1 insertions, 49 deletions

diff --git a/src/doc.c b/src/doc.c
index e361a86c1a1..5326195c6a0 100644
--- a/src/doc.c
+++ b/src/doc.c
@@ -341,56 +341,8 @@ string is passed through `substitute-command-keys'.  */)
   else if (MODULE_FUNCTIONP (fun))
     doc = module_function_documentation (XMODULE_FUNCTION (fun));
 #endif
-  else if (COMPILEDP (fun))
-    {
-      if (PVSIZE (fun) <= COMPILED_DOC_STRING)
-        return Qnil;
-      else
-        {
-          Lisp_Object tem = AREF (fun, COMPILED_DOC_STRING);
-          if (STRINGP (tem))
-            doc = tem;
-          else if (FIXNATP (tem) || CONSP (tem))
-            doc = tem;
-          else
-            return Qnil;
-        }
-    }
-  else if (STRINGP (fun) || VECTORP (fun))
-    {
-      return build_string ("Keyboard macro.");
-    }
-  else if (CONSP (fun))
-    {
-      Lisp_Object funcar = XCAR (fun);
-      if (!SYMBOLP (funcar))
-        xsignal1 (Qinvalid_function, fun);
-      else if (EQ (funcar, Qkeymap))
-        return build_string ("Prefix command (definition is a keymap associating keystrokes with commands).");
-      else if (EQ (funcar, Qlambda)
-               || (EQ (funcar, Qclosure) && (fun = XCDR (fun), 1))
-               || EQ (funcar, Qautoload))
-        {
-          Lisp_Object tem1 = Fcdr (Fcdr (fun));
-          Lisp_Object tem = Fcar (tem1);
-          if (STRINGP (tem))
-            doc = tem;
-          /* Handle a doc reference--but these never come last
-             in the function body, so reject them if they are last.  */
-          else if ((FIXNATP (tem) || (CONSP (tem) && FIXNUMP (XCDR (tem))))
-                   && !NILP (XCDR (tem1)))
-            doc = tem;
-          else
-            return Qnil;
-        }
-      else
-        goto oops;
-    }
   else
-    {
-    oops:
-      xsignal1 (Qinvalid_function, fun);
-    }
+    doc = call1 (intern ("function-documentation"), fun);
 
   /* If DOC is 0, it's typically because of a dumped file missing
      from the DOC file (bug in src/Makefile.in).  */