Like everything else, Dynamic Scoping is merely a tool. Used well it can make certain tasks easier. Used poorly it can introduce bugs and headaches. I can certainly see some uses for it. One can eliminate the need to pass variables to some functions. For instance, I might set the display up at the beginning … Read more
You can think of each appearance of module Something, class Something or def something as a “gateway” into a new scope. When Ruby is searching for the definition of a name that has been referenced it first looks in the current scope (the method, class or module), and if it isn’t found there it will … Read more
Unlike in a language like Python, a Javascript method forgets it is a method after you extract it and pass it somewhere else. You can either Wrap the method call inside an anonymous function This way, accessing the baz property and calling it happen at the same time, which is necessary for the this to … Read more
What’s going on? You say: feel like there is nothing special is going on here. The outer foo in bar increments the global x, and foo surrounded by let in bar increments the shadowed x. What’s the big deal? The special that’s going on here is that LET can shadow the value of *x*. With … Read more
<<- is most useful in conjunction with closures to maintain state. Here’s a section from a recent paper of mine: A closure is a function written by another function. Closures are so-called because they enclose the environment of the parent function, and can access all variables and parameters in that function. This is useful because … Read more
I understand them through examples. 🙂 First, lexical scope (also called static scope), in C-like syntax: void fun() { int x = 5; void fun2() { printf(“%d”, x); } } Every inner level can access its outer levels. There is another way, called dynamic scope used by the first implementation of Lisp, again in a … Read more