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;

Task/Queue-Definition/Jq/queue-definition-2.jq

@@ -0,0 +1,13 @@
+fifo | pop  # produces [null,[]]
+
+fifo
+ | push(42) # enqueue
+ | push(43) # enqueue
+ | pop      # dequeue
+ | .[0]     # the value
+# produces 43
+
+fifo|push(1) as $q1
+| fifo|push(2) as $q2
+| [($q1|pop|.[0]), ($q2|pop|.[0])]
+# produces: [1, 2]