New function: macroexpand-place.

* stdlib/place.tl (sys:pl-expand): Function renamed to
macroexpand-place; env parameter becomes optional.
(macroexpand-1-place): New function.
(place-form-p, call-update-expander, call-clobber-expander,
call-delete-expander): Follow rename.

* autoload.c (place_set_entries): Register symbols
macroexpand-place and macroexpand-1-place for autoload.

* txr.1: Documented.

* stdlib/doc-syms.tl: Updated.

4 files changed, 87 insertions, 8 deletions

diff --git a/autoload.c b/autoload.c
index a3430a63..336c2518 100644
--- a/autoload.c
+++ b/autoload.c
@@ -109,6 +109,7 @@ static val place_set_entries(val fun)
     lit("defplace"), lit("define-place-macro"), lit("define-modify-macro"),
     lit("placelet"), lit("placelet*"), lit("read-once"),
     lit("define-accessor"), lit("with-slots"),
+    lit("macroexpand-place"), lit("macroexpand-1-place"),
     nil
   };
 
diff --git a/stdlib/doc-syms.tl b/stdlib/doc-syms.tl
index d6c001c1..e75ad2c7 100644
--- a/stdlib/doc-syms.tl
+++ b/stdlib/doc-syms.tl
@@ -1185,8 +1185,10 @@
       ("macroexpand" "N-02ED5471")
       ("macroexpand-1" "N-02ED5471")
       ("macroexpand-1-lisp1" "N-01E62179")
+      ("macroexpand-1-place" "N-00684FF9")
       ("macroexpand-lisp1" "N-01E62179")
       ("macroexpand-params" "N-037EB49A")
+      ("macroexpand-place" "N-00684FF9")
       ("macrolet" "N-00AC12C0")
       ("madv-dontneed" "N-027D1E84")
       ("madv-normal" "N-027D1E84")
diff --git a/stdlib/place.tl b/stdlib/place.tl
index 07ee7be4..fcc86735 100644
--- a/stdlib/place.tl
+++ b/stdlib/place.tl
@@ -63,7 +63,7 @@
   (or [*place-macro* sym]
       (progn (sys:autoload-try-fun sym) [*place-macro* sym])))
 
-(defun sys:pl-expand (unex-place env)
+(defun macroexpand-place (unex-place : env)
   (while t
     (let ((place unex-place)
           pm-expander)
@@ -76,11 +76,18 @@
       (when (or (eq place unex-place)
                 (null place)
                 (and (atom place) (not (symbolp place))))
-        (return-from sys:pl-expand place))
+        (return-from macroexpand-place place))
       (sys:setq unex-place place))))
 
+(defun macroexpand-1-place (unex-place : env-unused)
+  (let ((pm-expander (if (consp unex-place)
+                       (sys:get-place-macro (car unex-place)))))
+    (if pm-expander
+      [pm-expander unex-place]
+      unex-place)))
+
 (defun place-form-p (unex-place env)
-  (let ((place (sys:pl-expand unex-place env)))
+  (let ((place (macroexpand-place unex-place env)))
     (or (bindable place)
         (and (consp place) [*place-update-expander* (car place)] t))))
 
@@ -147,7 +154,7 @@
 
 (defun call-update-expander (getter setter unex-place env body)
   (sys:propagate-ancestor body unex-place getter setter)
-  (let* ((place (sys:pl-expand unex-place env))
+  (let* ((place (macroexpand-place unex-place env))
          (expander (get-update-expander place))
          (sys:*pl-env* env)
          (sys:*pl-form* unex-place)
@@ -157,7 +164,7 @@
 
 (defun call-clobber-expander (ssetter unex-place env body)
   (sys:propagate-ancestor body unex-place ssetter)
-  (let* ((place (sys:pl-expand unex-place env))
+  (let* ((place (macroexpand-place unex-place env))
          (expander (get-clobber-expander place))
          (sys:*pl-env* env)
          (sys:*pl-form* unex-place)
@@ -167,7 +174,7 @@
 
 (defun call-delete-expander (deleter unex-place env body)
   (sys:propagate-ancestor body unex-place deleter)
-  (let* ((place (sys:pl-expand unex-place env))
+  (let* ((place (macroexpand-place unex-place env))
          (expander (get-delete-expander place))
          (sys:*pl-env* env)
          (sys:*pl-form* unex-place)
diff --git a/txr.1 b/txr.1
index 5d2f076f..9a3578b3 100644
--- a/txr.1
+++ b/txr.1
@@ -41713,12 +41713,12 @@ contains no parameter macro invocations, then it is returned.
 
 The optional
 .meta env
-parmeter specifies the macro environment which is passed to the
+parameter specifies the macro environment which is passed to the
 parameter macro expanders, which they can receive via the
 .code :env
 parameter. The default value
 .code nil
-sepcifies the top-level environment.
+specifies the top-level environment.
 
 .TP* Examples:
 
@@ -43865,6 +43865,75 @@ in terms of
     ^(car ,obj))
 .brev
 
+.coNP Functions @ macroexpand-place and @ macroexpand-1-place
+.synb
+.mets (macroexpand-1-place < form <> [ env ])
+.mets (macroexpand-place < form <> [ env ])
+.syne
+.desc
+If
+.meta form
+is a place macro form (a form whose operator symbol has been defined
+as a place macro using
+.codn define-place-macro )
+these functions expand the place macro form and return the expanded form.
+Otherwise, they return
+.metn form .
+
+.code macroexpand-place-1
+performs a single expansion, expanding only the place the macro
+that is referenced by the symbol in the first position of
+.metn form ,
+and returns the expansion. Note that if
+.meta form
+is an ordinary macro form, this function will not expand it,
+even if such an expansion would reveal a place macro form.
+
+.code macroexpand-place
+performs a full place expansion of
+.meta form
+by the following process.
+If
+.meta form
+is a place macro call, it is expanded, and the result is
+checked again to see whether it is a place macro, and
+expanded. This is repeated as many times as necessary
+until the result is no longer a place macro call.
+Then, if the resulting form is an ordinary macro invocation,
+it is expanded once as if by
+.codn macroexpand-1 .
+This process is iterated until a fixed point is reached.
+
+The optional
+.meta env
+parameter is a macro environment.  Note: the
+.code macroexpand-place-1
+function ignores the
+.meta env
+parameter, which could change in the future.
+
+.TP* Examples
+
+Given this ordinary macro definition
+
+.verb
+  (defmacro leftmost (x) ^(first ,x))
+.brev
+
+the following results are obtained:
+
+.verb
+  ;; ordinary macro leftmost expands to first,
+  ;; then first place macro expands to car:
+  (macroexpand-place '(leftmost x)) -> (car x)
+
+  ;; macroexpand-1-place won't expand ordinary macro:
+  (macroexpand-1-place '(leftmost x)) -> (leftmost x)
+
+  ;; macroexpand-1-place expands place macro
+  (macroexpand-1-place '(first x)) -> (car x)
+.brev
+
 .coNP Macro @ rlet
 .synb
 .mets (rlet >> ({( sym << init-form )}*) << body-form *)