Variable scope When you declare a local variable, that variable has a scope. Generally, local variables exist only within the block or function in which you declare them. function() { var a = 1; console.log(a); // works } console.log(a); // fails If I try to access a local variable, most languages will look for it … Read more
Iteration is a general term for taking each item of something, one after another. Any time you use a loop, explicit or implicit, to go over a group of items, that is iteration. In Python, iterable and iterator have specific meanings. An iterable is an object that has an __iter__ method which returns an iterator, … Read more
“Porcelain” is the material from which toilets are usually made (and sometimes other fixtures such as washbasins). This is distinct from “plumbing” (the actual pipes and drains), where the porcelain provides a more user-friendly interface to the plumbing. Git uses this terminology in analogy, to separate the low-level commands that users don’t usually need to … Read more
It basically means that the object implements the __getitem__() method. In other words, it describes objects that are “containers”, meaning they contain other objects. This includes strings, lists, tuples, and dictionaries.
Emulation is the process of mimicking the outwardly observable behavior to match an existing target. The internal state of the emulation mechanism does not have to accurately reflect the internal state of the target which it is emulating. Simulation, on the other hand, involves modeling the underlying state of the target. The end result of … Read more
A magic number is a direct usage of a number in the code. For example, if you have (in Java): public class Foo { public void setPassword(String password) { // don’t do this if (password.length() > 7) { throw new InvalidArgumentException(“password”); } } } This should be refactored to: public class Foo { public static … Read more
Runtime describes software/instructions that are executed while your program is running, especially those instructions that you did not write explicitly, but are necessary for the proper execution of your code. Low-level languages like C have very small (if any) runtime. More complex languages like Objective-C, which allows for dynamic message passing, have a much more … Read more
< stands for the less-than sign: < > stands for the greater-than sign: > ≤ stands for the less-than or equals sign: ≤ ≥ stands for the greater-than or equals sign: ≥
There isn’t really a standard name for this case convention, and there is disagreement over what it should be called. That said, as of 2019, there is a strong case to be made that kebab-case is winning: https://trends.google.com/trends/explore?date=all&q=kebab-case,spinal-case,lisp-case,dash-case,caterpillar-case spinal-case is a distant second, and no other terms have any traction at all. Additionally, kebab-case has … Read more
The original code for the Cocoa frameworks came from the NeXTSTEP libraries Foundation and AppKit (those names are still used by Apple’s Cocoa frameworks), and the NextStep engineers chose to prefix their symbols with NS. Because Objective-C is an extension of C and thus doesn’t have namespaces like in C++, symbols must be prefixed with … Read more