feature request: add .Clear method

[novadev94]

Currently, it's impossible to clear the OrderedMap keeping its capacity.

A simple implementation would be:

func (l *list[K, V]) Clear() {
	l.root = Element[K, V]{} // just in case K & V are pointer types
}

func (m *OrderedMap[K, V]) Clear() {    
	clear(m.kv)
	m.ll.Clear()
}

[elliotchance]

Happy to accept a PR for this. I see clear() was introduced in Go 1.21, so for backwards compatibility it shouldn't use that function in this implementation.

[novadev94]

I see orderedmap/v3 targets Go 1.23 with generics and iterators. Maybe this .Clear method will only be added to v3?

Doing a custom implementation for clear would be inefficient since mapclear is implemented in the runtime package.

[elliotchance]

Generics were released with Go 1.18. I'm saying you can implement a Clear method, but it cannot rely on new functionality in Go 1.23, at least until 1.23 becomes old enough that its sensible to expect clients to be running that.