limit/2 evals exp one time too many

Author: nicowilliams

src/builtin.jq

@@ -167,7 +167,14 @@ def until(cond; next):
      def _until:
          if cond then . else (next|_until) end;
      _until;
-def limit($n; exp): if $n < 0 then exp else label $out | foreach exp as $item ([$n, null]; if .[0] < 1 then break $out else [.[0] -1, $item] end; .[1]) end;
+def limit($n; exp):
+  if $n < 0 then exp else
+    label $out |
+    foreach exp as $item (
+      [$n, null];
+      if .[0] < 1 then break $out
+        else [.[0] -1, $item] end;
+      if .[0] == 0 then .[1], break $out else .[1] end) end;
 def isempty(g): 0 == ((label $go | g | (1, break $go)) // 0);
 def first(g): label $out | g | ., break $out;
 def last(g): reduce g as $item (null; $item);