Generally speaking, the approach I use in this kind of situation is to have both an interface and an abstract class. The interfaces defines, well, the interface. The abstract class is merely a helper. You really can’t go wrong with this approach. Interfaces give you the flexibility to change implementation. Abstract classes give you boilerplate … Read more
The reason why you can access “out of scope” or “free” variables in ECMAscript is the such called Scope chain. The scope chain is a special property from each Execution context. As mentioned several times before, a context object looks at least like: [[scope]] Variable / Activation Object “this” context value each time you access … Read more
A transaction is a unit of work that you want to treat as “a whole.” It has to either happen in full or not at all. A classical example is transferring money from one bank account to another. To do that you have first to withdraw the amount from the source account, and then deposit … Read more
This question isn’t as silly as it might seem to some. At least theoretically, something such as O(1/n) is completely sensible when we take the mathematical definition of the Big O notation: Now you can easily substitute g(x) for 1/x … it’s obvious that the above definition still holds for some f. For the purpose … Read more
A Y-combinator is a “functional” (a function that operates on other functions) that enables recursion, when you can’t refer to the function from within itself. In computer-science theory, it generalizes recursion, abstracting its implementation, and thereby separating it from the actual work of the function in question. The benefit of not needing a compile-time name … Read more
The limitation exists because MVC has already started rendering a view to the client. The effect of redirecting from this point is undefined. It could work perfectly, it could continue rendering the original view without redirecting, it could throw a different exception, etc. Since the result of performing this action is undefined, the framework blocks … Read more
The term “referential transparency” comes from analytical philosophy, the branch of philosophy that analyzes natural language constructs, statements and arguments based on the methods of logic and mathematics. In other words, it is the closest subject outside computer science to what we call programming language semantics. The philosopher Willard Quine was responsible for initiating the … Read more
The entire point of interfaces is to give you the flexibility to have your class be forced to implement multiple interfaces, but still not allow multiple inheritance. The issues with inheriting from multiple classes are many and varied and the wikipedia page on it sums them up pretty well. Interfaces are a compromise. Most of … Read more
The definition of an inline function doesn’t have to be in a header file but, because of the one definition rule (ODR) for inline functions, an identical definition for the function must exist in every translation unit that uses it. The easiest way to achieve this is by putting the definition in a header file. … Read more
One way of thinking about it is this: O(N^2) means for every element, you’re doing something with every other element, such as comparing them. Bubble sort is an example of this. O(N log N) means for every element, you’re doing something that only needs to look at log N of the elements. This is usually … Read more