Merge pull request #1837 from muhmuhten/limit_0

src/builtin.jq

@@ -168,9 +168,9 @@ def until(cond; next):
          if cond then . else (next|_until) end;
      _until;
 def limit($n; exp):
-  if $n < 0 then exp
+    if $n > 0 then label $out | foreach exp as $item ($n; .-1; $item, if . <= 0 then break $out else empty end)
-  else label $out | foreach exp as $item ($n; .-1; $item, if . <= 0 then break $out else empty end)
+    elif $n == 0 then empty
-  end;
+    else exp 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);

tests/jq.test

@@ -304,6 +304,14 @@ null
 [11,22,33,44,55,66,77,88,99]
 [11,22,33]
 
+[limit(0; error)]
+"badness"
+[]
+
+[limit(1; 1, error)]
+"badness"
+[1]
+
 [first(range(.)), last(range(.)), nth(0; range(.)), nth(5; range(.)), try nth(-1; range(.)) catch .]
 10
 [0,9,0,5,"nth doesn't support negative indices"]