Generics migration (#237)

* Generics migration

This attempts to migrate this library in the least invasive way by preserving as
much of the original API as possible. It does not change the tests in a
meaningful way nor does it attempt to upgrade any logic that can be simplified
or improved with generics. This is purely an API migration, and still requires a
lot of additional work to be fully ready.

* Fix a few broken tests around serialization

* Add v2 suffix

* Temporarily change mod name for testing

* Rename module to /v2

stacks/arraystack/arraystack.go

@@ -11,32 +11,33 @@ package arraystack
 
 import (
 	"fmt"
-	"github.com/emirpasic/gods/lists/arraylist"
-	"github.com/emirpasic/gods/stacks"
 	"strings"
+
+	"github.com/emirpasic/gods/v2/lists/arraylist"
+	"github.com/emirpasic/gods/v2/stacks"
 )
 
 // Assert Stack implementation
-var _ stacks.Stack = (*Stack)(nil)
+var _ stacks.Stack[int] = (*Stack[int])(nil)
 
 // Stack holds elements in an array-list
-type Stack struct {
-	list *arraylist.List
+type Stack[T comparable] struct {
+	list *arraylist.List[T]
 }
 
 // New instantiates a new empty stack
-func New() *Stack {
-	return &Stack{list: arraylist.New()}
+func New[T comparable]() *Stack[T] {
+	return &Stack[T]{list: arraylist.New[T]()}
 }
 
 // Push adds a value onto the top of the stack
-func (stack *Stack) Push(value interface{}) {
+func (stack *Stack[T]) Push(value T) {
 	stack.list.Add(value)
 }
 
 // Pop removes top element on stack and returns it, or nil if stack is empty.
 // Second return parameter is true, unless the stack was empty and there was nothing to pop.
-func (stack *Stack) Pop() (value interface{}, ok bool) {
+func (stack *Stack[T]) Pop() (value T, ok bool) {
 	value, ok = stack.list.Get(stack.list.Size() - 1)
 	stack.list.Remove(stack.list.Size() - 1)
 	return
@@ -44,29 +45,29 @@ func (stack *Stack) Pop() (value interface{}, ok bool) {
 
 // Peek returns top element on the stack without removing it, or nil if stack is empty.
 // Second return parameter is true, unless the stack was empty and there was nothing to peek.
-func (stack *Stack) Peek() (value interface{}, ok bool) {
+func (stack *Stack[T]) Peek() (value T, ok bool) {
 	return stack.list.Get(stack.list.Size() - 1)
 }
 
 // Empty returns true if stack does not contain any elements.
-func (stack *Stack) Empty() bool {
+func (stack *Stack[T]) Empty() bool {
 	return stack.list.Empty()
 }
 
 // Size returns number of elements within the stack.
-func (stack *Stack) Size() int {
+func (stack *Stack[T]) Size() int {
 	return stack.list.Size()
 }
 
 // Clear removes all elements from the stack.
-func (stack *Stack) Clear() {
+func (stack *Stack[T]) Clear() {
 	stack.list.Clear()
 }
 
 // Values returns all elements in the stack (LIFO order).
-func (stack *Stack) Values() []interface{} {
+func (stack *Stack[T]) Values() []T {
 	size := stack.list.Size()
-	elements := make([]interface{}, size, size)
+	elements := make([]T, size, size)
 	for i := 1; i <= size; i++ {
 		elements[size-i], _ = stack.list.Get(i - 1) // in reverse (LIFO)
 	}
@@ -74,7 +75,7 @@ func (stack *Stack) Values() []interface{} {
 }
 
 // String returns a string representation of container
-func (stack *Stack) String() string {
+func (stack *Stack[T]) String() string {
 	str := "ArrayStack\n"
 	values := []string{}
 	for _, value := range stack.list.Values() {
@@ -85,6 +86,6 @@ func (stack *Stack) String() string {
 }
 
 // Check that the index is within bounds of the list
-func (stack *Stack) withinRange(index int) bool {
+func (stack *Stack[T]) withinRange(index int) bool {
 	return index >= 0 && index < stack.list.Size()
 }