Allow op arguments like @1 to be places.

* share/txr/stdlib/place.tl: Introducing new defplace
for (sys:var ...) which is treated as if it were a symbol,
in anticipation of the op/do macro placing that syntax
with a symbol.

2 files changed, 15 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 998d3dab..0c2fb2df 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2015-07-03  Kaz Kylheku  <kaz@kylheku.com>
+
+	Allow op arguments like @1 to be places.
+
+	* share/txr/stdlib/place.tl: Introducing new defplace
+	for (sys:var ...) which is treated as if it were a symbol,
+	in anticipation of the op/do macro placing that syntax
+	with a symbol.
+
 2015-07-02  Kaz Kylheku  <kaz@kylheku.com>
 
 	Support trailing semicolon after hex/octal characters.
diff --git a/share/txr/stdlib/place.tl b/share/txr/stdlib/place.tl
index 9bb39347..72e054fd 100644
--- a/share/txr/stdlib/place.tl
+++ b/share/txr/stdlib/place.tl
@@ -291,6 +291,12 @@
                    (tree-bind ,args (cdr ,place)
                       ,delete-body)))))))))
 
+(defplace (sys:var arg) body
+  (getter setter
+    ^(macrolet ((,getter () ^(sys:var ,',arg))
+                (,setter (val) ^(sys:setq ,'(sys:var ,arg) ,val)))
+       ,body)))
+
 (defplace (car cell) body
   (getter setter
     (with-gensyms (cell-sym)