Re: a property "definition-type" would help find macro-defined tests

[Stephen Gildea <stepheng+emacs@gildea.com>]

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I have made the changes requested and one other:

 - added a NEWS entry

 - find-function-search-for-symbol doc string additions
   trimmed of detail that is available from the manual.

 - in the manual, added an index entry for the new property,
   definition-type, and for all the existing properties that
   did not have index entries (which was most of them).

 - in the code example, put each top-level form in @group.

 - new in this version of the patch: added a cross reference
   from where Coding Conventions discusses how to write macros
   that define functions.



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diff --git a/etc/NEWS b/etc/NEWS
index 37e5669b139..50928cd9264 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1137,6 +1137,13 @@ It offers a more concise way to create a completion table with metadata.
 +++
 ** 'all-completions' and 'unintern' no longer support old calling conventions.
 
++++
+** New property 'definition-type' used by find-function and friends.
+Macros that define an object in a way makes the object's name and the
+macro call site defining the object hard to associate can put the
+property 'definition-type' on the object's name to provide instructions
+for finding the definition.
+
 \f
 * Changes in Emacs 31.1 on Non-Free Operating Systems
 
diff --git a/lisp/emacs-lisp/find-func.el b/lisp/emacs-lisp/find-func.el
index 0837b37023e..643b6aba2a6 100644
--- a/lisp/emacs-lisp/find-func.el
+++ b/lisp/emacs-lisp/find-func.el
@@ -400,9 +400,12 @@ find-function-search-for-symbol
 Visit the library in a buffer, and return a cons cell (BUFFER . POSITION),
 or just (BUFFER . nil) if the definition can't be found in the file.
 
-If TYPE is nil, look for a function definition.
-Otherwise, TYPE specifies the kind of definition,
-and it is interpreted via `find-function-regexp-alist'.
+If TYPE is nil, look for a function definition,
+otherwise, TYPE specifies the kind of definition.
+If SYMBOL has a property `definition-type',
+the property value is used instead of TYPE.
+TYPE is interpreted via `find-function-regexp-alist'.
+
 The search is done in the source for library LIBRARY."
   (if (null library)
       (error "Don't know where `%s' is defined" symbol))
@@ -410,6 +413,8 @@ find-function-search-for-symbol
   ;; that defines something else.
   (while (and (symbolp symbol) (get symbol 'definition-name))
     (setq symbol (get symbol 'definition-name)))
+  (setq type (or (get symbol 'definition-type)
+                 type))
   (if (string-match "\\`src/\\(.*\\.\\(c\\|m\\)\\)\\'" library)
       (find-function-C-source symbol (match-string 1 library) type)
     (when (string-match "\\.el\\(c\\)\\'" library)
diff --git a/doc/lispref/symbols.texi b/doc/lispref/symbols.texi
index 24b4e892024..7990e2a8f75 100644
--- a/doc/lispref/symbols.texi
+++ b/doc/lispref/symbols.texi
@@ -510,35 +510,54 @@ Standard Properties
 
 @table @code
 @item :advertised-binding
+@cindex @code{:advertised-binding} property
 This property value specifies the preferred key binding, when showing
 documentation, for the named function.  @xref{Keys in Documentation}.
 
 @item char-table-extra-slots
+@cindex @code{char-table-extra-slots} property
 The value, if non-@code{nil}, specifies the number of extra slots in
 the named char-table type.  @xref{Char-Tables}.
 
 @item customized-face
+@cindex @code{customized-face} property
 @itemx face-defface-spec
+@cindex @code{face-defface-spec} property
 @itemx saved-face
+@cindex @code{saved-face} property
 @itemx theme-face
+@cindex @code{theme-face} property
 These properties are used to record a face's standard, saved,
 customized, and themed face specs.  Do not set them directly; they are
 managed by @code{defface} and related functions.  @xref{Defining
 Faces}.
 
 @item customized-value
+@cindex @code{customized-value} property
 @itemx saved-value
+@cindex @code{saved-value} property
 @itemx standard-value
+@cindex @code{standard-value} property
 @itemx theme-value
+@cindex @code{theme-value} property
 These properties are used to record a customizable variable's standard
 value, saved value, customized-but-unsaved value, and themed values.
 Do not set them directly; they are managed by @code{defcustom} and
 related functions.  @xref{Variable Definitions}.
 
 @item definition-name
-This property is used to find the definition of a symbol in the source
-code, when it might be hard to find the definition by textual search
-of the source file.  For example, a @code{define-derived-mode}
+@cindex @code{definition-name} property
+@itemx definition-type
+@cindex @code{definition-type} property
+These properties help find the definition of a symbol in the source
+code when it might be hard to find the definition by textual search
+of the source file.
+The Emacs Help commands such as @kbd{C-h f} (@pxref{Help,,,
+emacs, The GNU Emacs Manual}) use these properties to show the definition
+of a symbol via a button in the @file{*Help*} buffer where the
+symbol's documentation is shown.
+
+For example, a @code{define-derived-mode}
 (@pxref{Derived Modes}) might define a mode-specific function or a
 variable implicitly; or your Lisp program might generate a run-time
 call to @code{defun} to define a function (@pxref{Defining
@@ -547,43 +566,101 @@ Standard Properties
 be found by textual search and whose code defines the original symbol.
 In the example with @code{define-derived-mode}, the value of this
 property of the functions and variables it defines should be the mode
-symbol.  The Emacs Help commands such as @kbd{C-h f} (@pxref{Help,,,
-emacs, The GNU Emacs Manual}) use this property to show the definition
-of a symbol via a button in the @file{*Help*} buffer where the
-symbol's documentation is shown.
+symbol.
+
+In some cases, the definition cannot be found by looking for the
+definition of another symbol.  For example, a test file might use a
+macro to generate calls to @code{ert-deftest}
+(@pxref{,,,ert, ERT: Emacs Lisp Regression Testing}) where the code
+is boiler plate and only varying data need to be passed in.
+In such cases, the @code{definition-type} property of the symbol can
+be a symbol that has an entry in @code{find-function-regexp-alist}
+telling how to find the definition of symbols of this type.
+
+In the example of a macro defining calls to @code{ert-deftest},
+the macro could put the property @code{definition-type} on each
+test defined.  The file defining the macro would also define a
+definition-finding function or regexp and add it to
+@code{find-function-regexp-alist} after that variable is loaded.
+Here is an example using a function to find the definition:
+
+@example
+@group
+(defmacro define-foo-test (data)
+  "Define a test of the foo system using DATA."
+  (declare (debug (&rest sexp)))
+  (let ((test-name (intern (concat ...))))
+    `(progn
+      (put ',test-name 'definition-type 'foo-test-type)
+      (ert-deftest ,test-name ()
+        ,(concat "Test foo with " ...)
+        ...))))
+@end group
+@end example
+
+@example
+@group
+(defun foo-find-test-def-function (test-name)
+  "Search for the `define-foo-test' call defining TEST-NAME.
+Return non-nil if the definition is found."
+  (save-match-data
+    (let ((regexp ...))
+      (save-restriction
+        (widen)
+        (goto-char (point-min))
+        (re-search-forward regexp nil t)))))
+@end group
+@end example
+
+@example
+@group
+(with-eval-after-load "find-func"
+  (add-to-list
+   'find-function-regexp-alist
+   '(foo-test-type . foo-find-test-def-function)))
+@end group
+@end example
 
 @item disabled
+@cindex @code{disabled} property
 If the value is non-@code{nil}, the named function is disabled