Why does the type of linkedliststack need to be comparable

[oliverdain]

I don't see any operations on linkedliststack that would actually require comparisons but the type bound is:

// New nnstantiates a new empty stack
func New[T comparable]() *Stack[T] {
	return &Stack[T]{list: singlylinkedlist.New[T]()}
}

[06kellyjac]

Because linkedliststack.Stack needs a singlylinkedlist.List[T comparable] and it can't be changed to any so it also needs to be [T comparable]

gods/lists/singlylinkedlist/singlylinkedlist.go

Line 142 in 1d83d5a

if element.value == value {

❯ go build ./...
# github.com/emirpasic/gods/v2/lists/singlylinkedlist
lists/singlylinkedlist/singlylinkedlist.go:142:7: invalid operation: element.value == value (incomparable types in type set)
lists/singlylinkedlist/singlylinkedlist.go:169:6: invalid operation: element == value (incomparable types in type set)

If you didn't need Contains or IndexOf it wouldn't need comparable AFAICT. Those functions don't seem to be used by other functions on singlylinkedlist.List or by the parent linkedliststack.Stack.

[oliverdain]

@06kellyjac I see. I didn't notice the Contains or IndexOf method. Note that Stack doesn't have either of those methods so it does not require that type contraint except for the implementation detail that it's built on top of singlylinkedlist. How would you feel about:

• Introduce a singlylinkedlist.NonCompList which is exactly what singlylinkedlist.List is today except it doesn't contain Contains or IndexOf and it has a type bound of any.
• singlylinkedlist.List embeds singlylinkedlist.NonCompList and then adds the Contains and IndexOf methods.
• linkedliststack is built on top of singlylinkedlist.NonCompList and has a type bound of any

If that seems like a reasonable plan I can send in a PR to implement that. Also, I realize that singlylinkedlist.NonCompList is a terrible name - open to suggestions.

[06kellyjac]

Maybe ListAny 🤷

I'm not a maintainer so it's up to you. :)