GoDS

This is a repository of data structures built with the new generics functionality in Go 1.18.

This is not necessarily meant for public consumption, but rather as a learning exercise. That said, if you find use in these, mores the better.

Structures are built on top of idiomatic Go types; e.g. slices rather than arrays since array capacities are part of the type and it is not possible to make an open-ended generic-length array, and use idiomatic error returns.

Structures

List

List implements a doubly-linked list. It is created with the NewList[T]() function, which returns a pointer to a new, empty list. Items in the list are the Node type, which encapsulates the value.

Node

`Node represents a linked list node. It has the following methods:

• func (n *Node[T]) Next() *Node[T]: returns the node behind the receiver, or nil if the receiver is the back of the list.
• func (n *Node[T]) Prev() *Node[T]: returns the node in front of the receiver, or nil if the recevier is the front of the list.

List supports the following operations:

• func (*List[T]) InsertBefore(*Node[T], T): adds a value before the provided node in the list. If the node pointer is nil, adds the value to the back of the list.
• func (*List[T]) InsertAfter(*Node[T], T): adds a value after the provided node in the list. If the node pointer is nil, adds the value to the front of the list.
• func (*List[T]) InsertFront(T): adds a value to the front of the list. Equivalent to InsertAfter(nil, T)
• func (*List[T]) InsertBack(T): adds a value to the back of the list. Equivalent to InsertBefore(nil, T)
• func (*List[T]) Remove(*Node[T]) error: removes a node from the list, repointing the surrounding nodes accordingly. Returns ErrNilNode if the provided node pointer is nil.

Stack

Stack implements a generic LIFO stack data structure backed by a slice. It is created with the NewStack[T]() function, which returns a pointer to a new, empty stack. It has supports following operations:

• func (*Stack[T]) Push(T): push an item onto the top of the stack
• func (*Stack[T]) Peek() (T, error): return the value on top of the stack without removing it. Returns ErrStackEmpty if the stack is empty.
• func (*Stack[T]) Pop() (T, error): remove the value on top of the stack and return it. Returns ErrStackEmpty if the stack is empty.

Queue

Queue implements a generic FIFO queue data structure backed by a List. It is created with the NewQueue[T]() function, which returns a pointer to a new, empty queue. It supports the following operations:

• func (*Queue[T]) Push(T): pushes an item to the back of the queue.
• func (*Queue[T]) Peek() (T, error): returns the item at the front of the queue, or ErrQueueEmpty if the queue is empty.
• func (*Queue[T]) Pop() (T, error): remove the value at the front of the queue and return it. Returns ErrQueueEmpty if the queue is empty.

Deque

Deque implements a generic double-ended queue backed by a slice. Deque attempts to be efficient and uses the slice as a ring buffer to avoid excessive reallocations. It is created with the NewDeque[T]() function, which returns a pointer to a new, empty deque with a minimum capacity of 8. The minimum capacity can be customized through the use of NewDequeWithCap[T](int). Passing a capacity less than 1 will panic. Deque supports the following operations:

• func (*Deque[T]) PushBack(T): pushes an item to the back of the deque.
• func (*Deque[T]) PushFront(T): pushes an item to the front of the deque.
• func (*Deque[T]) PopBack() (T, error): remove the value at the back of the deque and return it. Returns ErrDequeEmpty if the deque is empty.
• func (*Deque[T]) PopFront() (T, error): remove the value at the back of the deque and return it. Returns ErrDequeEmpty if the deque is empty.
• func (*Deque[T]) PeekBack() (T, error): return the value at the back of the deque without removing it. Returns ErrDequeEmpty if the deque is empty.
• func (*Deque[T]) PeekFront() (T, error): return the value at the front of the deque without removing it. Returns ErrDequeEmpty if th deque is empty.