* eval.c (eval_init): not added as synonym for null.

* lib.c (copy_list): Use list_collect_append rather than
list_collect_terminate.
(append2, appendv): Simplified using new list_collect_append.
(nappend2): Simplified using new list_collect_nconc.

* lib.h (list_collect): Added check for accidental usage
of list_collect after list_append, since PTAIL has different
semantics.
(list_collect_nconc, list_collect_append):  Semantics fixed so that
append collecting works more like the Common Lisp append function,
allowing trailing atoms or a lone atom. The meaning of PTAIL is
changed, however.  Now PTAIL actually tracks the head of the most
recently appended segment. Each append operation has to first
traverse the previously added piece to get to the end.

(list_collect_terminate): Macro removed.

* match.c (v_gather): Removed useless use of list_collect_terminate.

* parser.y: Some headers added that are needed by list_collect.

* txr.1: Documented append, list, atom, null, not, consp, make-lazy-cons,
lcons-fun, listp, proper-listp, length-list,  mapcar, mappend, and apply.

1 files changed, 13 insertions, 25 deletions

diff --git a/lib.c b/lib.c
index 8e1652e7..9c3f1e34 100644
--- a/lib.c
+++ b/lib.c
@@ -319,14 +319,14 @@ val push(val value, val *plist)
 
 val copy_list(val list)
 {
-  list_collect_decl (out, tail);
+  list_collect_decl (out, ptail);
 
   while (consp(list)) {
-    list_collect(tail, car(list));
+    list_collect(ptail, car(list));
     list = cdr(list);
   }
 
-  list_collect_terminate(tail, list);
+  list_collect_append(ptail, list);
 
   return out;
 }
@@ -359,14 +359,11 @@ val reverse(val in)
 
 val append2(val list1, val list2)
 {
-  list_collect_decl (out, tail);
+  list_collect_decl (out, ptail);
 
-  while (list1) {
-    list_collect(tail, car(list1));
-    list1 = cdr(list1);
-  }
+  list_collect_append (ptail, list1);
+  list_collect_append (ptail, list2);
 
-  list_collect_terminate(tail, list2);
   return out;
 }
 
@@ -376,14 +373,9 @@ val appendv(val lists)
 
   for (; lists; lists = cdr(lists)) {
     val item = car(lists);
-    if (consp(item)) {
-      list_collect_append(ptail, car(lists));
-    } else {
-      if (cdr(lists))
-        uw_throwf(error_s, lit("append: ~s is not a list"), item, nao);
-      list_collect_terminate(ptail, item);
-      return out;
-    }
+    if (listp(*ptail))
+      uw_throwf(error_s, lit("append: ~s is not a list"), *ptail, nao);
+    list_collect_append(ptail, item);
   }
 
   return out;
@@ -391,16 +383,12 @@ val appendv(val lists)
 
 val nappend2(val list1, val list2)
 {
-  val temp, iter;
-
-  if (list1 == nil)
-    return list2;
+  list_collect_decl (out, ptail);
 
-  for (iter = list1; (temp = cdr(iter)) != nil; iter = temp)
-    ; /* empty */
+  list_collect_nconc (ptail, list1);
+  list_collect_nconc (ptail, list2);
 
-  *cdr_l(iter) = list2;
-  return list1;
+  return out;
 }
 
 val ldiff(val list1, val list2)