feat(stdlib): add Queue.size and Stack.size (#647)

* feat: add Queue.size function

* feat: add Stack.size function

compiler/test/stdlib/queue.test.gr

@@ -26,3 +26,9 @@ assert Queue.isEmpty(Queue.pop(Queue.push(1, empty)))
 assert Queue.isEmpty(Queue.pop(Queue.pop(Queue.pop(sampleQueue))))
 assert Queue.peek(Queue.pop(sampleQueue)) == Some(2)
 assert Queue.peek(Queue.pop(Queue.push(4, Queue.pop(sampleQueue)))) == Some(3)
+
+// Queue.size
+
+assert Queue.size(empty) == 0
+assert Queue.size(sampleQueue) == 3
+assert Queue.size(Queue.pop(Queue.pop(sampleQueue))) == 1

compiler/test/stdlib/stack.test.gr

@@ -26,3 +26,9 @@ assert Stack.isEmpty(Stack.pop(Stack.push(1, empty)))
 assert Stack.isEmpty(Stack.pop(Stack.pop(Stack.pop(sampleStack))))
 assert Stack.peek(Stack.pop(sampleStack)) == Some(2)
 assert Stack.peek(Stack.pop(Stack.push(4, Stack.pop(sampleStack)))) == Some(2)
+
+// Stack.size
+
+assert Stack.size(empty) == 0
+assert Stack.size(sampleStack) == 3
+assert Stack.size(Stack.pop(Stack.pop(sampleStack))) == 1

stdlib/queue.gr

@@ -50,3 +50,12 @@ export let pop = (queue) => {
   @deprecated Please use `Queue.pop` instead. `Queue.dequeue` will be removed in v0.4.0.
 */
 export let dequeue = pop;
+
+export let size = (queue) => {
+    match (queue) {
+        { forwards: [], backwards: [] } => 0,
+        { forwards, backwards: [] } => List.length(forwards),
+        { forwards: [], backwards } => List.length(backwards),
+        { forwards, backwards } => List.length(forwards) + List.length(backwards),
+    }
+}

stdlib/stack.gr

@@ -40,3 +40,10 @@ export let pop = (stack) => {
         { data: [head, ...tail] } => { data: tail, }
     }
 }
+
+export let size = (stack) => {
+    match (stack) {
+        { data: [] } => 0,
+        { data } => List.length(data)
+    }
+}