New generic function `oclosure-interactive-form`

It's used by `interactive-form` when it encounters an OClosure.
This lets one compute the `interactive-form` of OClosures
dynamically by adding appropriate methods.
This does not include support for `command-modes` for Oclosures.

* lisp/simple.el (oclosure-interactive-form): New generic function.

* src/data.c (Finteractive_form): Delegate to
`oclosure-interactive-form` if the arg is an OClosure.
(syms_of_data): New symbol `Qoclosure_interactive_form`.
* src/eval.c (Fcommandp): Delegate to `interactive-form` if the arg is
an OClosure.

* src/lisp.h (VALID_DOCSTRING_P): New function, extracted from
`store_function_docstring`.
* src/doc.c (store_function_docstring): Use it.

* lisp/kmacro.el (kmacro): Don't carry any interactive form.
(oclosure-interactive-form) <kmacro>: New method, instead.

* test/lisp/emacs-lisp/oclosure-tests.el (oclosure-interactive-form)
<oclosure-test>: New method.
(oclosure-test-interactive-form): New test.

* doc/lispref/commands.texi (Using Interactive):
Document `oclosure-interactive-form`.

1 files changed, 21 insertions, 0 deletions

diff --git a/test/lisp/emacs-lisp/oclosure-tests.el b/test/lisp/emacs-lisp/oclosure-tests.el
index b6bdebc0a2b..b3a921826b1 100644
--- a/test/lisp/emacs-lisp/oclosure-tests.el
+++ b/test/lisp/emacs-lisp/oclosure-tests.el
@@ -106,6 +106,27 @@
       (and (eq 'error (car err))
            (string-match "Duplicate slot: fst$" (cadr err)))))))
 
+(cl-defmethod oclosure-interactive-form ((ot oclosure-test))
+  (let ((snd (oclosure-test--snd ot)))
+    (if (stringp snd) (list 'interactive snd))))
+
+(ert-deftest oclosure-test-interactive-form ()
+  (should (equal (interactive-form
+                  (oclosure-lambda (oclosure-test (fst 1) (snd 2)) () fst))
+                 nil))
+  (should (equal (interactive-form
+                  (oclosure-lambda (oclosure-test (fst 1) (snd 2)) ()
+                    (interactive "r")
+                    fst))
+                 '(interactive "r")))
+  (should (equal (interactive-form
+                  (oclosure-lambda (oclosure-test (fst 1) (snd "P")) () fst))
+                 '(interactive "P")))
+  (should (not (commandp
+                (oclosure-lambda (oclosure-test (fst 1) (snd 2)) () fst))))
+  (should (commandp
+           (oclosure-lambda (oclosure-test (fst 1) (snd "P")) () fst))))
+
 (oclosure-define (oclosure-test-mut
                   (:parent oclosure-test)
                   (:copier oclosure-test-mut-copy))