[elpa] externals/auto-overlays 2b02fa5 83/93: Allow single symbols in auto-overlays-in property tests as a convenience.

[Stefan Monnier]

branch: externals/auto-overlays
commit 2b02fa567f3786cea23fd7f3d5af51b12f0443ac
Author: Toby S. Cubitt <toby-predictive@dr-qubit.org>
Commit: Toby S. Cubitt <toby-predictive@dr-qubit.org>

    Allow single symbols in auto-overlays-in property tests as a convenience.
---
 auto-overlays.el | 64 +++++++++++++++++++++++++++++++-------------------------
 1 file changed, 35 insertions(+), 29 deletions(-)

diff --git a/auto-overlays.el b/auto-overlays.el
index be56c3f..f5fe8d3 100644
--- a/auto-overlays.el
+++ b/auto-overlays.el
@@ -558,6 +558,8 @@ Any remaining arguments (which *must* come after any keyword
 arguments) specify property tests, each of which should be a list
 with one of the following forms:
 
+  PROPERTY
+
   (FUNCTION PROPERTY)
 
   (FUNCTION PROPERTY VALUE)
@@ -571,9 +573,13 @@ For each overlay between START and END, first the values
 corresponding to the property names are retrieved from the
 overlay, then FUNCTION is called with the properties values
 followed by the other values as its arguments. The test is
-satisfied if the result is non-nil, otherwise it fails. Tests are
-evaluated in order, but only up to the first failure. Only
-overlays that satisfy all property tests are returned."
+satisfied if the result is non-nil, otherwise it fails.
+
+A PROPERTY symbol on its own tests whether that property has a
+non-null value, equivalent to (identity PROPERTY).
+
+Tests are evaluated in order, but only up to the first failure.
+Only overlays that satisfy all property tests are returned."
 
   ;; remove any keyword arguments from PROP-TESTS
   (setq prop-tests
@@ -590,39 +596,39 @@ overlays that satisfy all property tests are returned."
   (let (overlay-list function prop-list value-list result)
     ;; check properties of each overlay in region
     (dolist (o (overlays-in start end))
-      ;; check overlay is entirely within region
-      (if (and within
-              (or (< (overlay-start o) start) (> (overlay-end o) end)))
-         (setq result nil)
-
-       ;; if it is, or we don't care
-       (setq result t)
-       (catch 'failed
-         ;; check if properties match
-         (dolist (test prop-tests)
-           ;; (Note: the whole thing would be neater with something like
-           ;; (apply 'and (map ...)) but 'and is a special form, not a
-           ;; function, so can't be applied)
+      (catch 'failed
+       ;; check overlay is entirely within region
+       (when (and within
+                  (or (< (overlay-start o) start)
+                      (> (overlay-end o) end)))
+         (throw 'failed nil))
+
+       ;; check if properties match
+       ;; Note: The whole thing would be neater with something like (apply
+       ;;       #'and (map ...)) but `and' is a special form, not a function
+       (dolist (test prop-tests)
+         ;; single property
+         (if (symbolp test)
+             (when (null (overlay-get o test)) (throw 'failed nil))
+           ;; propery test
            (setq function (nth 0 test))
            (unless (listp (setq prop-list (nth 1 test)))
              (setq prop-list (list prop-list)))
            (setq value-list nil)
            (unless (or (< (length test) 3)
-                       (and (setq value-list (nth 2 test))  ; nil isn't list
-                            (listp value-list)))
+                       (and (setq value-list (nth 2 test))
+                            (listp value-list)))            ; nil isn't list
              (setq value-list (list value-list)))
-
            ;; apply the test
-           (setq result
-                 (and result
-                      (apply function
-                             (append (mapcar (lambda (p) (overlay-get o p))
-                                             prop-list)
-                                     value-list))))
-           (when (null result) (throw 'failed nil)))))
-
-      ;; add overlay to result list if its properties matched
-      (when result (push o overlay-list)))
+           (unless (apply function
+                          (append (mapcar (lambda (p) (overlay-get o p))
+                                          prop-list)
+                                  value-list))
+             (throw 'failed nil))))
+
+       ;; add overlay to result list if its properties matched
+       (push o overlay-list)))
+
     ;; return result list
     (nreverse overlay-list)))