Named arguments may be just "syntax sugar" but its one of the biggest things I miss from Haskell. They make library functions more consistent and they also make it much easier to write point free code because you don't need to resort to combinators like "flip" or "." as much.
I believe they are slightly beyond "syntax sugar". If I'm mistaken, I'd love to see the equivalent of what they desugar to. Some of the nuances that I believe OCaml's named arguments get right (and what greatly distinguishes them from passing a record) may require additional work in the type system beyond simple desugaring to something like records. Someone please correct me if I'm wrong.
- Partially applying arguments. You can apply one named argument, and get a function that expects the remaining named arguments. This is pretty great though confusing when you see it for the first time.
- Defaults for omitted arguments. If the caller doesn't specify an argument, you can define what should be used instead. This is kind of like the opposite of subtyping on record arguments. With structurally subtyped record arguments, you can pass a record that has more information than a certain minimum set of labeled fields. But with named optional arguments with defaults, you can pass less than a certain maximum number of labeled fields.
