* share/txr/stdlib/place.tl (place-form-p): New function.

* lisplib.c (place_set_entries): Add place-form-p to list of names.

3 files changed, 12 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index d4e45401..0a4a21d9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2015-07-12  Kaz Kylheku  <kaz@kylheku.com>
+
+	* share/txr/stdlib/place.tl (place-form-p): New function.
+
+	* lisplib.c (place_set_entries): Add place-form-p to list of names.
+
 2015-07-11  Kaz Kylheku  <kaz@kylheku.com>
 
 	Expand away sys:lisp1-value based on lexical info.
diff --git a/lisplib.c b/lisplib.c
index be437634..bc00b6a1 100644
--- a/lisplib.c
+++ b/lisplib.c
@@ -59,6 +59,7 @@ static val place_set_entries(val dlt, val fun)
     lit("*place-delete-expander*"),
     lit("get-update-expander"), lit("get-clobber-expander"),
     lit("get-delete-expander"),
+    lit("place-form-p"),
     lit("rlet"), lit("with-gensyms"),
     lit("call-update-expander"), lit("call-clobber-expander"),
     lit("call-delete-expander)"),
diff --git a/share/txr/stdlib/place.tl b/share/txr/stdlib/place.tl
index 7bb059a8..f7e468cf 100644
--- a/share/txr/stdlib/place.tl
+++ b/share/txr/stdlib/place.tl
@@ -82,6 +82,11 @@
                      (makunbound ',',place-expr))))
        ,*op-body))
 
+  (defun place-form-p (place)
+    (when (or (bindable place)
+              (and (consp place) [*place-update-expander* (car place)]))
+      t))
+
   (defun get-update-expander (place)
     (cond
       ((symbolp place) (fun sys:sym-update-expander))