* lib.c (getplist_f): New function.

* lib.h (getplist_f): Declared.

* match.c (v_collect, h_coll): Use getplist_f to distinguish
the case that :vars is explicitly specified as (). In this
case, no bindings escape from the collect.

* tests/008/soundex.txr: This test case broke due to using
:vars () and yet counting on the variable to exist.

* RELNOTES: Updated.

6 files changed, 38 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index d1a658c5..73ec56fd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,20 @@
 2011-11-24  Kaz Kylheku  <kaz@kylheku.com>
 
+	* lib.c (getplist_f): New function.
+
+	* lib.h (getplist_f): Declared.
+
+	* match.c (v_collect, h_coll): Use getplist_f to distinguish
+	the case that :vars is explicitly specified as (). In this
+	case, no bindings escape from the collect.
+
+	* tests/008/soundex.txr: This test case broke due to using
+	:vars () and yet counting on the variable to exist.
+
+	* RELNOTES: Updated.
+
+2011-11-24  Kaz Kylheku  <kaz@kylheku.com>
+
 	* match.c (match_funcall): Set source location info for
 	generated function call.
 
diff --git a/RELNOTES b/RELNOTES
index 810e8d0d..3058ee29 100644
--- a/RELNOTES
+++ b/RELNOTES
@@ -6,6 +6,10 @@
   - Fixed regression in source location tracking (line numbers
     shown in debugger and trace output).
 
+  - Fixed :vars () in collect/coll not working as intended.
+    This should prevent any bindings from being collected, and
+    allows iteration with collect without accumulating memory.
+
 
                                     TXR 043
                                    2011-11-23
diff --git a/lib.c b/lib.c
index 1076bb2c..440b258e 100644
--- a/lib.c
+++ b/lib.c
@@ -677,6 +677,20 @@ val getplist(val list, val key)
   return nil;
 }
 
+val getplist_f(val list, val key, val *found)
+{
+  for (; list; list = cdr(cdr(list))) {
+    val ind = first(list);
+    if (eq(ind, key)) {
+      *found = t;
+      return second(list);
+    }
+  }
+
+  *found = nil;
+  return nil;
+}
+
 val proper_plist_to_alist(val list)
 {
   list_collect_decl (out, tail);
diff --git a/lib.h b/lib.h
index 4ad5e7a0..e6677a51 100644
--- a/lib.h
+++ b/lib.h
@@ -315,6 +315,7 @@ val listp(val obj);
 val proper_listp(val obj);
 val length(val list);
 val getplist(val list, val key);
+val getplist_f(val list, val key, val *found);
 val proper_plist_to_alist(val list);
 val improper_plist_to_alist(val list, val boolean_keys);
 val num(cnum val);
diff --git a/match.c b/match.c
index dce83a45..7f34efc9 100644
--- a/match.c
+++ b/match.c
@@ -2261,7 +2261,8 @@ static val v_collect(match_files_ctx *c)
   val mintimes = getplist(args, mintimes_k);
   val maxtimes = getplist(args, maxtimes_k);
   val lines = getplist(args, lines_k);
-  val vars = getplist(args, vars_k);
+  val have_vars;
+  val vars = getplist_f(args, vars_k, &have_vars);
   cnum cmax = nump(gap) ? c_num(gap) : (nump(max) ? c_num(max) : 0);
   cnum cmin = nump(gap) ? c_num(gap) : (nump(min) ? c_num(min) : 0);
   cnum mincounter = cmin, maxcounter = 0;
@@ -2356,7 +2357,7 @@ static val v_collect(match_files_ctx *c)
           val binding = car(iter);
           val vars_binding = assoc(vars, car(binding));
 
-          if (!vars || vars_binding) {
+          if (!have_vars || vars_binding) {
             val existing = assoc(bindings_coll, car(binding));
 
             bindings_coll = acons_new(bindings_coll, car(binding),
diff --git a/tests/008/soundex.txr b/tests/008/soundex.txr
index d01fb76d..b192bb62 100644
--- a/tests/008/soundex.txr
+++ b/tests/008/soundex.txr
@@ -56,7 +56,7 @@
 @###
 @# process arguments and list soundex codes
 @###
-@(collect :vars ())
+@(collect :vars (input))
 @input
 @  (output :filter (:fun soundex))
 @input