Add online-help support to describe types

* lisp/help-fns.el (describe-symbol-backends): Move to help-mode.el.
(describe-symbol): Improve the selection of default.

* lisp/help-mode.el: Require cl-lib.
(describe-symbol-backends): Move from help-fns.el.
(help-make-xrefs): Use it.

* lisp/emacs-lisp/cl-extra.el (describe-symbol-backends): Add entry
for types.
(cl--typedef-regexp): New const.
(find-function-regexp-alist): Add entry for types.
(cl-help-type, cl-type-definition): New buttons.
(cl-find-class): New function.
(cl-describe-type): New command.
(cl--describe-class, cl--describe-class-slot)
(cl--describe-class-slots): New functions, moved from eieio-opt.el.

* lisp/emacs-lisp/cl-generic.el (cl--generic-method-documentation)
(cl--generic-all-functions, cl--generic-specializers-apply-to-type-p):
New functions.  Moved from eieio-opt.el.
(cl--generic-class-parents): New function, extracted from
cl--generic-struct-specializers.
(cl--generic-struct-specializers): Use it.

* lisp/emacs-lisp/cl-macs.el (cl-defstruct): Use pcase-dolist.
Improve constructor's docstrings.
(cl-struct-unknown-slot): New error.
(cl-struct-slot-offset): Use it.

* lisp/emacs-lisp/cl-preloaded.el (cl-struct-define): Record the type
definition in current-load-list.

* lisp/emacs-lisp/eieio-core.el (eieio--known-slot-names): New var.
(eieio--add-new-slot): Set it.
(eieio-defclass-internal): Use new name for current-load-list.
(eieio-oref): Add compiler-macro to warn about unknown slots.
* lisp/emacs-lisp/eieio.el (defclass): Update eieio--known-slot-names
as compile-time as well.  Improve constructor docstrings.

* lisp/emacs-lisp/eieio-opt.el (eieio-help-class)
(eieio--help-print-slot, eieio-help-class-slots): Move to cl-extra.el.
(eieio-class-def): Remove button.
(eieio-help-constructor): Use new name for load-history element.
(eieio--specializers-apply-to-class-p, eieio-all-generic-functions)
(eieio-method-documentation): Move to cl-generic.el.
(eieio-display-method-list): Use new names.

* lisp/emacs-lisp/lisp-mode.el (lisp-imenu-generic-expression):
Add "define-linline".
(lisp-fdefs): Remove "defsubst".
(el-fdefs): Add "defsubst", "cl-defsubst", and "define-linline".

* lisp/emacs-lisp/macroexp.el (macroexp--warned): New var.
(macroexp--warn-and-return): Use it to avoid inf-loops.
Add `compile-only' argument.

1 files changed, 10 insertions, 12 deletions

diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el
index 5bcf0882791..f5e1ffb0008 100644
--- a/lisp/emacs-lisp/cl-macs.el
+++ b/lisp/emacs-lisp/cl-macs.el
@@ -2722,20 +2722,16 @@ non-nil value, that slot cannot be set via `setf'.
          (push `(defalias ',copier #'copy-sequence) forms))
     (if constructor
 	(push (list constructor
-		       (cons '&key (delq nil (copy-sequence slots))))
-		 constrs))
-    (while constrs
-      (let* ((name (caar constrs))
-             (rest (cdr (pop constrs)))
-             (args (car rest))
-             (doc  (cadr rest))
-	     (anames (cl--arglist-args args))
+                    (cons '&key (delq nil (copy-sequence slots))))
+              constrs))
+    (pcase-dolist (`(,cname ,args ,doc) constrs)
+      (let* ((anames (cl--arglist-args args))
 	     (make (cl-mapcar (function (lambda (s d) (if (memq s anames) s d)))
 			    slots defaults)))
-	(push `(cl-defsubst ,name
+	(push `(cl-defsubst ,cname
                    (&cl-defs (nil ,@descs) ,@args)
-                 ,@(if (stringp doc) (list doc)
-                     (if (stringp docstring) (list docstring)))
+                 ,(if (stringp doc) (list doc)
+                    (format "Constructor for objects of type `%s'." name))
                  ,@(if (cl--safe-expr-p `(progn ,@(mapcar #'cl-second descs)))
                        '((declare (side-effect-free t))))
                  (,(or type #'vector) ,@make))
@@ -2859,6 +2855,8 @@ slots skipped by :initial-offset may appear in the list."
               descs)))
     (nreverse descs)))
 
+(define-error 'cl-struct-unknown-slot "struct %S has no slot %S")
+
 (defun cl-struct-slot-offset (struct-type slot-name)
   "Return the offset of slot SLOT-NAME in STRUCT-TYPE.
 The returned zero-based slot index is relative to the start of
@@ -2868,7 +2866,7 @@ does not contain SLOT-NAME."
   (declare (side-effect-free t) (pure t))
   (or (gethash slot-name
                (cl--class-index-table (cl--struct-get-class struct-type)))
-      (error "struct %s has no slot %s" struct-type slot-name)))
+      (signal 'cl-struct-unknown-slot (list struct-type slot-name))))
 
 (defvar byte-compile-function-environment)
 (defvar byte-compile-macro-environment)