New placelet macro.

* lisplib.c (place_set_entries): Add placelet to list of names.

* share/txr/stdlib/place.tl (sys:placelet1, placelet): New macros.
(defplace dwim): Do not retrieve the
place's value into a local variable and have the getter
expand to that variable. Rather, have the getter retrieve the
value. A getter that refers to a cached copy breaks
the semantics of placelet, and any place operator which can
evaluate the location after it is stored.

* txr.1: Documented placelet.

1 files changed, 1 insertions, 0 deletions

diff --git a/lisplib.c b/lisplib.c
index 2a0357a5..9db0853d 100644
--- a/lisplib.c
+++ b/lisplib.c
@@ -68,6 +68,7 @@ static val place_set_entries(val dlt, val fun)
     lit("push"), lit("pop"), lit("swap"), lit("shift"), lit("rotate"),
     lit("pushnew"), lit("del"),
     lit("defplace"), lit("define-modify-macro"),
+    lit("placelet"),
     nil
   };