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Comment by NateDad | Hacker News Reader

Actually readability at the point of use is very reader-friendly:

    machines := db.GetAllMachines()
    sort.Sort(byName(machines))

For those not familiar with Go, the sort.Sort line is converting the list of machines into a type that matches the interface that sort.Sort expects. The list of machines is sorted in-place

The only part that can be subtly changed is the Less function, which determines the sort order. And as I've said elsewhere... that definition of sort order is something you have to define in any language (for non-trivial types).

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What does the implementation of `byName` look like? I'm not sure I understand what its return type would be.

Either sort.Interface or a type that implements sort.Interface

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.

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?

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".

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