CompareAndStore would be nice

[lkarlslund]

For concurrent programs a compare and swap value would be really neat, as you might have a race if multiple threads are doing:

value, _ := map.Load(key)
value.Modify()
map.Store(key, value)

The pattern could be changed to

for {
  oldvalue, _ := map.Load(key)
  newvalue := oldvalue
  newvalue.Modify()
  success := map.CompareAndStore(key, oldvalue, newvalue)
  if success {
    break
  }
}

[alphadose]

Yes this is useful, will add it in the next release 👍

[lkarlslund]

Also variants like LoadOrCalculate would be pretty awesome (same behaviour as LoadOrStore, but you give it a function that returns the value to store, for complex or costly generators of values). The xsync module (https://github.com/puzpuzpuz/xsync) has those, if you need some inspiration.
But really great job on this module so far!

[alphadose]

@lkarlslund

Also variants like LoadOrCalculate would be pretty awesome (same behaviour as LoadOrStore, but you give it a function that returns the value to store, for complex or costly generators of values).

This is similar to #16

[bagualing]

Could you also consider adding two atomic APIs: Swap and CompareAndSwap?

func (m *Map[K, V]) Swap(key K, newValue V) (oldValue V){}
func (m *Map[K, V]) CompareAndSwap(Key K, oldValue, newValue V) (swapped bool){}

I have encountered this requirement in my usage scenario, so, I think it's mybee useful too.

[alphadose]

@bagualing CompareAndSwap is the same as CompareAndStore described by @lkarlslund above
I have taken note of Swap API and shall add it as well

[alphadose]

@lkarlslund @bagualing both CompareAndSwap and Swap have been added with 5f15ec7