Sorry I misread your example as a single list argument. Strictly speaking, you can not call a function with no arguments in Elm, but some functions take Unit as an argument.
There are a couple of roadblocks preventing this exact functionality in Elm. Firstly, Elm does not allow recursive types <https://ellie-app.com/5YDsxhFLSa1/0>. Secondly, a name in Elm must have the same type everywhere it is mentioned. Even normal function overloading is not possible <https://ellie-app.com/5YDsxhFLSa1/1> without renaming the function. The closest I could come up with was this <https://ellie-app.com/g4DpfMDxPa1/1>, which I don't think will be very satisfactory to you, but I believe is isomorphic to the Haskell example. You just have to explicitly name all of the function applications in Elm. On Nov 6, 2017 11:53 AM, "Ray Toal" <ray.t...@gmail.com> wrote: Thanks but I was looking not for the obvious, practical approach for summing integers but was interested in the puzzle of arbitrary-length currying. When called with no arguments, the function should yield its sum so far. When called with a single argument, the function should return a function that knows about what it has seen so far. It sounds stateful, but can be done without state. But since Elm is statically typed and doesn't have overloading, I'm wondering if this can even be done with currying. On Monday, November 6, 2017 at 4:23:21 AM UTC-8, David Andrews wrote: > The solution for the list version is very straightforward in elm: > https://ellie-app.com/g4DpfMDxPa1/0 > > On Sun, Nov 5, 2017 at 10:39 PM, Ray Toal <ray....@gmail.com> wrote: > >> There's an interesting problem on the Programming Puzzles and Stack >> Exchange on arbitrary length currying here: https://codegolf.stackex >> change.com/questions/117017/arbitrary-length-currying. It asks for a >> function f behaving as follows: >> >> f () = 0 >> f (3)(9)(2)() = 14 >> >> This is trivial in dynamically typed languages that don't care about the >> number of arguments, and is easy to do in statically typed languages which >> allow overloading. But what about the ML-like languages? >> >> The only ML-like language with a solution is Haskell. Its author says >> "Forcing >> Haskell's strict type system to allow this requires some magic, namely, >> enabling the GHC extension for flexible typeclass instances." >> >> Is this problem impossible in Elm? >> >> If impossibie, can a solution be found to a related problem, say where >> the arguments are lists?, e.g. >> >> f [] = 0 >> f [3] [9] [2] [] = 14 >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Elm Discuss" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to elm-discuss...@googlegroups.com. >> >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
