ON{-APPLY,}-CHANGE: always return result of primary propapp

In particular, if the secondary propapps are applied but make no change, do
not return :NO-CHANGE as the overall result.

Signed-off-by: Sean Whitton <spwhitton@spwhitton.name>

1 files changed, 6 insertions, 7 deletions

diff --git a/src/combinator.lisp b/src/combinator.lisp
index 772ac6c..26a6767 100644
--- a/src/combinator.lisp
+++ b/src/combinator.lisp
@@ -286,14 +286,13 @@ in order."
                            (apply #'propattrs prop args)
                            (propappattrs on-change))
               :apply (lambda (&rest args)
-                       (if (eql :no-change (apply #'propapply prop args))
-                           :no-change
-                           (propappapply on-change)))
+                       (aprog1 (apply #'propapply prop args)
+                         (unless (eql it :no-change)
+                           (propappapply on-change))))
               :unapply (lambda (&rest args)
-                         (let ((result (apply #'propunapply prop args)))
-                           (cond ((eql :no-change result) :no-change)
-                                 (unapply (propappapply on-change))
-                                 (t result))))
+                         (aprog1 (apply #'propunapply prop args)
+                           (when (and unapply (not (eql it :no-change)))
+                             (propappapply on-change))))
               :args (cdr propapp))))
 
 (defmacro as (user &body properties)