Add TryPop to stack, vector, queue (#91)

builtin_set_test.go

@@ -23,7 +23,7 @@ func Test_MakeBuiltinSet2(t *testing.T) {
 	expectEq(t, s.IsEmpty(), true)
 }
 
-func Test_MakeBuiltinSetOf(t *testing.T) {
+func Test_SetOf(t *testing.T) {
 	s := SetOf("hello", "world")
 	expectEq(t, s.Len(), 2)
 }

dlist.go

@@ -95,7 +95,25 @@ func (l *DList[T]) PushBack(val T) {
 }
 
 // PopFront popups a element from the front of the list.
-func (l *DList[T]) PopFront() (T, bool) {
+func (l *DList[T]) PopFront() T {
+	r, ok := l.TryPopFront()
+	if !ok {
+		panic("DList.PopFront: empty list")
+	}
+	return r
+}
+
+// PopBack popups a element from the back of the list.
+func (l *DList[T]) PopBack() T {
+	r, ok := l.TryPopBack()
+	if !ok {
+		panic("DList.PopBack: empty list")
+	}
+	return r
+}
+
+// TryPopFront tries to popup a element from the front of the list.
+func (l *DList[T]) TryPopFront() (T, bool) {
 	var val T
 	if l.length == 0 {
 		return val, false
@@ -107,8 +125,8 @@ func (l *DList[T]) PopFront() (T, bool) {
 	return val, true
 }
 
-// PopBack popups a element from the back of the list.
-func (l *DList[T]) PopBack() (T, bool) {
+// TryPopBack tries to popup a element from the back of the list.
+func (l *DList[T]) TryPopBack() (T, bool) {
 	var val T
 	if l.length == 0 {
 		return val, false

dlist_test.go

@@ -51,46 +51,52 @@ func Test_DList_PushBack(t *testing.T) {
 }
 
 func Test_DList_PopFront(t *testing.T) {
-	l := NewDList[int]()
-	_, ok := l.PopFront()
+	l := NewDListOf(1, 2)
+	expectEq(t, l.PopFront(), 1)
+	n, ok := l.TryPopFront()
+	expectEq(t, n, 2)
+	expectTrue(t, ok)
+	n, ok = l.TryPopFront()
 	expectFalse(t, ok)
+	expectPanic(t, func() { l.PopFront() })
 }
 
 func Test_DList_PopBack(t *testing.T) {
-	l := NewDList[int]()
-	_, ok := l.PopBack()
+	l := NewDListOf(1, 2)
+	expectEq(t, l.PopBack(), 2)
+	n, ok := l.TryPopBack()
+	expectTrue(t, ok)
+	expectEq(t, n, 1)
+	n, ok = l.TryPopBack()
 	expectFalse(t, ok)
+	expectPanic(t, func() { l.PopBack() })
 }
 
 func Test_DList_PushBack_PopFront(t *testing.T) {
 	l := NewDList[int]()
 	l.PushBack(1)
-	v, ok := l.PopFront()
-	expectTrue(t, ok)
+	v := l.PopFront()
 	expectEq(t, v, 1)
 }
 
 func Test_DList_PushBack_PopBack(t *testing.T) {
 	l := NewDList[int]()
 	l.PushBack(1)
-	v, ok := l.PopBack()
-	expectTrue(t, ok)
+	v := l.PopBack()
 	expectEq(t, v, 1)
 }
 
 func Test_DList_PushFront_PopBack(t *testing.T) {
 	l := NewDList[int]()
 	l.PushFront(1)
-	v, ok := l.PopBack()
-	expectTrue(t, ok)
+	v := l.PopBack()
 	expectEq(t, v, 1)
 }
 
 func Test_DList_PushFront_PopFront(t *testing.T) {
 	l := NewDList[int]()
 	l.PushFront(1)
-	v, ok := l.PopFront()
-	expectTrue(t, ok)
+	v := l.PopFront()
 	expectEq(t, v, 1)
 }