idiomatic

I can do this quite easily, and cleanly, using a for loop. For instance, if I wanted to traverse a Seq from every element back to itself I would do the following: val seq = Seq(1,2,3,4,5) for (i <- seq.indices) { for (j <- seq.indices) { print(seq(i + j % seq.length)) } } But as I'm looking to fold over the collection, I'm wondering if there is a more idiomatic approach. A recursive approach would allow me to avoid any var s. But basically, I'm wondering if something like the following is possible: seq.rotatedView(i) Which would create a rotated view, like rotating bits (or circular shift).

I am currently learning Rust and looking to use it for developing a GUI based application with GTK+. My problem relates to registering callbacks to respond to GTK events/signals and mutating state within those callbacks. I have a working but inelegant solution, so I would like to ask if there is a cleaner, more idiomatic solution. I have implemented my code as a struct with method implementations, where the struct maintains references to the GTK widgets along with other state that it needs. It constructs a closure that is passed to the GtkWidget::connect* functions in order to receive events,

The ES5 language spec clearly states that Error(foo) does the same thing as new Error(foo) . But I notice that in the wild, the longer new Error(foo) form is much more common. Is there some reason for this? Is there any situation where using new Error(foo) is preferable to using Error(foo) ? Is there some reason for this? It's simply the habit of always calling constructors with new . Consistency rules! It's a good practice to do even when they work without new , and recommended by several style guides and related tooling. Btw, since ES6 Error is subclassible , and its subclasses will require

This question already has answers here : Closed 3 years ago . Why is “!=” used with iterators instead of “<”? (2 answers) I have been asked this question which I do not really know why. If you have a pointer int * x; You can compare pointers with > and < because it stands for the memory location something like 0x0000 0x0004 0x0008 , etc. I know iterators and pointers are different, but they act in a very similar way. For example: vector<int> myVector; for(int i = 1; i < 101; i++) { myVector.push_back(i); } vector<int>::iterator it = myVector.begin(); while(it != myVector.end()) //Why can't we

I seem to have faced this problem many times and I wanted to ask the community whether I am just barking up the wrong tree. Basically my question can be distilled down to this: if I have an enum (in Java) for which the values are important, should I be using an enum at all or is there a better way, and if I do use an enum then what is the best way to reverse the lookup? Here's an example. Suppose I want to create a bean representing a specific month and year. I might create something like the following: public interface MonthAndYear { Month getMonth(); void setMonth(Month month); int getYear()

I like to learn a new language by making small tool like calculator. Although I already searched a lot idiomatic examples about specific cases(such as idiomatic usage of array and list), I have no idea how to put those together to write this small calculator in an idiomatic way. So here is my code: (defn pre-process [s] "Seperate operands with operators and replace ( with l, ) with r" (re-seq #"\d+|[\+\-\*\/lr]" (clojure.string/replace s #"\(|\)" {"(" "l" ")" "r"}))) (defn calc-once [stk] "Take one operator from operator stack and apply it to top two numbers in operand stack" (let [opt (:opt