bracket: bug: wrong result when function is applied.

Reported by user vapnik spaknik.

* lib.c (bracket): Don't rely on the index variable to step
through the arguments, because it only counts fixed arguments.
The args_get function doesn't increment the index beyond
args->fill; when popping arguments from args->list, index
stays unmodified.

* tests/016/arith.tl: Tests for bracket added.

2 files changed, 18 insertions, 4 deletions

diff --git a/lib.c b/lib.c
index c76c4864..3b2aa4af 100644
--- a/lib.c
+++ b/lib.c
@@ -3341,15 +3341,15 @@ val clamp(val low, val high, val num)
 
 val bracket(val larg, struct args *args)
 {
-  cnum index = 0;
+  cnum index = 0, i = 0;
 
-  while (args_more(args, index)) {
+  for (; args_more(args, index); i++) {
     val rarg = args_get(args, &index);
     if (less(larg, rarg))
-      return num(index - 1);
+      return num(i);
   }
 
-  return num(index);
+  return num(i);
 }
 
 val string_own(wchar_t *str)
diff --git a/tests/016/arith.tl b/tests/016/arith.tl
index eaa7fe2f..6a99b24a 100644
--- a/tests/016/arith.tl
+++ b/tests/016/arith.tl
@@ -57,3 +57,17 @@
 (test (digits 3 2) (1 1))
 (test (digits 7 2) (1 1 1))
 (test (digits 8 2) (1 0 0 0))
+
+(test (bracket 0 10 20 30) 0)
+(test (bracket 9 10 20 30) 0)
+(test (bracket 10 10 20 30) 1)
+(test (bracket 15 10 20 30) 1)
+(test (bracket 25 10 20 30) 2)
+(test (bracket 30 10 20 30) 3)
+
+(test [apply bracket '(0 10 20 30)] 0)
+(test [apply bracket '(9 10 20 30)] 0)
+(test [apply bracket '(10 10 20 30)] 1)
+(test [apply bracket '(15 10 20 30)] 1)
+(test [apply bracket '(25 10 20 30)] 2)
+(test [apply bracket '(30 10 20 30)] 3)