Orthogonality is the property that means “Changing A does not change B”. An example of an orthogonal system would be a radio, where changing the station does not change the volume and vice-versa. A non-orthogonal system would be like a helicopter where changing the speed can change the direction. In programming languages this means that … Read more
Matters of practicality are highly subjective, so I will simply say that learning different language paradigms will only serve to make you a better programmer. What is more practical than that? Functional, Haskell – I know you said that you didn’t want to, but you should really really reconsider. You’ve gotten some functional exposure with … Read more
This gives a signed angle for any angles: a = targetA – sourceA a = (a + 180) % 360 – 180 Beware in many languages the modulo operation returns a value with the same sign as the dividend (like C, C++, C#, JavaScript, full list here). This requires a custom mod function like so: … Read more
An invariant is more “conceptual” than a variable. In general, it’s a property of the program state that is always true. A function or method that ensures that the invariant holds is said to maintain the invariant. For instance, a binary search tree might have the invariant that for every node, the key of the … Read more
The following answer is from Gof book (Design Patterns) An object’s class defines how the object is implemented. The class defines object’s internal state and the implementation of its operations. In contrast, an object’s type only refers to its interface – a set of requests to which it can respond. An object can have many … Read more
There are three levels: Eager loading: you do everything when asked. Classic example is when you multiply two matrices. You do all the calculations. That’s eager loading; Lazy loading: you only do a calculation when required. In the previous example, you don’t do any calculations until you access an element of the result matrix; and … Read more
Parameters are the things defined by functions as input, arguments are the things passed as parameters. void foo(int bar) { … } foo(baz); In this example, bar is a parameter for foo. baz is an argument passed to foo.
When someone defines a universal type ∀X they’re saying: You can plug in whatever type you want, I don’t need to know anything about the type to do my job, I’ll only refer to it opaquely as X. When someone defines an existential type ∃X they’re saying: I’ll use whatever type I want here; you … Read more
Let’s say you go to the dentist to have a tooth pulled out. When the receptionist asks you for your name, that’s information they need in order to begin the appointment. In this example, your name is contextual information. So in the context of visiting the dentist, you need to provide your name to get … Read more
Everybody who is anti-goto cites, directly or indirectly, Edsger Dijkstra’s GoTo Considered Harmful article to substantiate their position. Too bad Dijkstra’s article has virtually nothing to do with the way goto statements are used these days and thus what the article says has little to no applicability to the modern programming scene. The goto-less meme … Read more