On: Proposal: Go should have generics

[natefinch]

byName is a type. It's a named type based (likely) on a slice of machines. The byName type implements the functions necessary to support the interface that the sort.Sort function requires:

    type byName []Machine
    
    func (b byName) Len() int { return len(b) }
    func (b byName) Swap(i, j int) { b[j], b[i] = b[i], [b[j] }
    func (b byName) Less(i, j int) { return b[i].Name < b[j].Name }

sort.Sort takes an interface type that has the methods Len, Swap, and Less, as defined in the signatures above, and uses them in a sorting algorithm which sorts the values in-place.

[akavi → natefinch]

Does all of that have to be implemented every time you want to sort by a new predicate?

If so, that seems like quite a lot of boilerplate, no?

[natefinch → akavi]

Mostly, yes (you can finagle your way out of rewriting Len and Swap if all you need to do is change the Less function, but it's probably not worth it from a code clarity point of view).

In a million lines of code, this costs us approximately 114 extra lines of code beyond the minimum necessary for any language where you need to specify a sort order (assuming you need at least one line of code per type/sort algo to tell the computer how to sort your random list of objects).

So, it depends on what you mean by a "lot".