I don’t think there is any way to have attributes apply to the later parts of such an “upvalue” pattern definition. One alternative is to use pure functions with attributes. Not as convenient as pattern matching, but when you evaluate f[2+2][8/4], it actually gives a result Curry would have liked. (“Function” is Mathematica’s “lambda”, if … Read more
Someone has already implememented this on the Clojure group. You can specify how many args a function has, and it will curry itself for you until it gets that many. The reason this doesn’t happen by default in Clojure is that we prefer variadic functions to auto-curried functions, I suppose.
Let’s have a look at def foldLeftViaFoldRight[A,B](l: List[A], z: B)(f: (B,A) => B): B = foldRight(l, (b:B) => b)((a,g) => b => g(f(b,a)))(z) (the other fold is similar). The trick is that during the right fold operation, we don’t build the final value of type B. Instead, we build a function from B to B. … Read more
You are not making a mistake. The key idea to understand here is currying – that a Haskell function of two arguments can be seen in two ways. The first is as simply a function of two arguments. If you have, for example, (+), this is usually seen as taking two arguments and adding them. … Read more
I found a paper by Laurent Dami that discusses currying in C/C++/Objective-C: More Functional Reusability in C/C++/Objective-c with Curried Functions Of interest to how it is implemented in C: Our current implementation uses existing C constructs to add the currying mechanism. This was much easier to do than modifying the compiler, and is sufficient to … Read more
It is hard to give a static type to the apply function, since its type depends on the type of the (possibly heterogeneous) list argument. There are at least two ways one way to write this function in Haskell that I can think of: Using reflection We can defer type checking of the application until … Read more
Currying is when you break down a function that takes multiple arguments into a series of functions that each take only one argument. Here’s an example in JavaScript: function add (a, b) { return a + b; } add(3, 4); // returns 7 This is a function that takes two arguments, a and b, and … Read more
EDIT: As noted in comments, this is partial application rather than currying. I wrote a blog post on my understanding of the difference, which folks may find interesting. Well, it’s not particularly different – but I’d separate out the currying part from the “calling DoSomething” part: public static Func<TResult> Apply<TResult, TArg> (Func<TArg, TResult> func, TArg … Read more
The def declares a method within a surrounding object/class/trait, similar to the way you define methods in Java. You can only use defs within other objects/classes/traits. In the REPL, you cannot see the surrounding object because it’s “hidden”, but it does exist. You cannot assign a def to a value, because the def is not … Read more
You could take a Map as cache and take nested maps for all following arguments. This cache works for arbitrary count of arguments and reuses the values from the former calls. It works by taking a curried function and an optional Map. If the map is not supplied, a new map is created which serves … Read more