September 2017 Update

Task/Queue-Definition/Jq/queue-definition-1.jq

@@ -0,0 +1,10 @@
+# An empty queue:
+def fifo: [];
+
+def push(e): [e] + .;
+
+def pop: [.[0], .[1:]];
+
+def pop_or_error: if length == 0 then error("pop_or_error") else pop end;
+
+def empty: length == 0;