bugfix: drop-while wasn't dropping the last element

1 files changed, 5 insertions, 2 deletions

diff --git a/neb/std/core.py b/neb/std/core.py
index 9a9e56d..ea80d86 100644
--- a/neb/std/core.py
+++ b/neb/std/core.py
@@ -126,15 +126,18 @@ def interpretDropWhile(symbol, args, env, ns):
     ev = None
     which_idx = None
     for idx, item in enumerate(coll.args):
-        which_idx = idx
         new_env.register("_item_", evaluate(item, env, ns))
         for arg in args[1:]:
             ev = evaluate(arg, new_env, ns)
         if not isinstance(ev, Bool):
             raise InterpretPanic(symbol, "condition must evaluate to a :bool", ev)
         if ev.value is False:
+            which_idx = idx
             break
-    return List(coll.args[which_idx:])
+    if which_idx is not None:
+        return List(coll.args[which_idx:])
+    else:
+        return List([])
 
 CORE.register("drop-while", NebSyntax("drop-while", interpretDropWhile, [for_each_arg, for_body_arg], for_body_arg))