Comments on: Burned by hoisting

By: Bradley

Bradley — Fri, 30 Oct 2009 18:21:47 +0000

Eric, the whole point of this post is that AS’s “hosting” feature is useless and the compiler ought to warn about usages that represent programming errors 99.9999% of the time. If that’s not getting “burned”, then what is?

Take your semantic arguments elsewhere, you pusillanimous git.

By: Jon Toland

Jon Toland — Wed, 08 Apr 2009 18:54:03 +0000

JavaScript actually has a JSLint tool that warns for this and other ECMAScript oddities. I’d love to see that integrated with Flex Builder in addition to getting live feedback while typing about syntactic warnings and errors prior to compilation. As for “hoisting” the next version of ActionScript will provide scoped declaration using the “let” keyword.

By: rich

rich — Fri, 20 Mar 2009 21:29:00 +0000

yes, thanks Eric, you’ve summed it up nicely.

By: Eric

Eric — Fri, 20 Mar 2009 21:22:48 +0000

This is semantics. It appears you are using the word “burned” to imply the compiler was not as helpful as it could be. And true that.

But, if the vo in line 2 was intended to reference a class member rather than the local variable defined in line 5, the more common application of the word “burned” might apply — the compiler made changes without warning that caused problems. It doesn’t sound like that was what happened, though (nor should it, because the compiler would track each variable, in it’s appropriate scope, with a unique identifier.

That said, whether the compiler promotes the variables or not, it is good practice to a) declare variables before they are used; b) declare variables just before they are used.

It would, however, be helpful to folks less-versed in traditional development practices if a compiler flag enabled warnings about conditions like the one you’ve mentioned.

Cheers.

By: rich

rich — Fri, 20 Mar 2009 06:50:02 +0000

By burned I meant that normally when someone makes a mistake such as that, you’d expect the compiler to catch it…but it didn’t “fix it”, it let the obvious mistake slide by without any warning or error notices.

By: w3master

w3master — Thu, 19 Mar 2009 22:59:12 +0000

In what way were you “burned”?

You wrote some duff code, used a variable before you declared it, and the compiler fixed it for you?