// Package ptr provides a generic interface for accessing an ordered
// collection of values sequentially, updating it and appending to it
// using a pointer (or cursor) type that keeps track of the current
// position. There are also implementations based on single
// scalar values, object attributes, or accessors.
package ptr

type Ptr[V any] interface {
	Append(V) Ptr[V]
	Insert(V, int) Ptr[V]
	Next() Ptr[V]
	Value() V
	Set(V) Ptr[V]
	Size() int
	Started() bool
	Seek(int) Ptr[V]
	Reset() Ptr[V]
	Clone() Ptr[V]
	New() Ptr[V]
	Copy() Ptr[V]
}

// generic functions

func New[V any](p Ptr[V]) Ptr[V] {
	np := p.Clone()
	np.Reset()
	return np
}

func Copy[V any](p, np Ptr[V]) Ptr[V] {
	op := p.New()
	for op.Next() != nil {
		np.Append(op.Value())
	}
	np.Reset()
	return np
}