Comment by ulisesrmzroche | Hacker News Reader

Comment by ulisesrmzroche | Hacker News Reader

Parent Full thread

Thing is that it actually matters in JS because declaring a function this way triggers the hoisting mechanism, so named functions are in scope within the entire function in which it is declared, regardless of block nesting.

If one isn't careful, and because JS doesn't have the visual delineator of blocks, instead all these rules you have to memorize, this could easily could lead to bugs, especially in large code-bases.

I think it's good to rely on closures to keep from polluting your scopes and to not use uneccesary function names, which is going to lead to one giant imperative statement (the one with the sequence of commands for the computer to perform) rather than a lot of little functions that you can pass around. Secrets of the JS ninja goes really in depth about this.

There is no such thing as an actual hoisting mechanism. Yes, declared functions are available anywhere in the surrounding scope, just like in any other language. It would be ridiculous if for example you couldn't call a method in Java inside another method unless it was syntactically placed before the target.

Global scope pollution is completely irrelevant here - declarations are available in the surrounding scope, not global. If the surrounding scope is global (which it never is in node.js), then that's your problem.

I don't think that's true about the hoisting mechanism. The javascript interpreter looks ahead to find all the var and functions and hoists them to the top of the function. I don't how know Java deals with forward-references, it was already considered passe before I even got into this stuff.

Also, where did I write anything about global scope? I said it was good to rely on closures to keep from polluting your scopes, and that there was no need for with unnecessary function names. You're literally belittling me out on things I didn't even write. Am I upvote-target practice here or something?

In the ML family of languages (e.g. OCaml, F#) declarations are only visible to code that occurs syntactically later. This has obvious disadvantages, but also the benefit of making dependencies obvious.

Yes I fell into the "all languages" trap. Maybe "most mainstream languages" is more in line with what I meant. :P

    test()

    def test():
        print "Hello."

Reply on news.ycombinator.com