restrictions on let declarations
concavelenz at gmail.com
Thu Jan 30 11:59:56 PST 2014
Yes, that was my point, that is has to be allowed currently and this is a
change. Using what incorrectly? Existing "const" and "function"
implementations? Or if "scoped" declarations?
On Thu, Jan 30, 2014 at 11:35 AM, Oliver Hunt <oliver at apple.com> wrote:
> On Jan 30, 2014, at 11:27 AM, John Lenz <concavelenz at gmail.com> wrote:
> I don't argue that it isn't a useless "let". I do point out that in
> "sloppy" mode, that other declaration are allow in practices by browsers.
> Chrome allows function, const, and var in the body of an if without block.
> That's because they _have_ to be allowed as these constructs are used on
> millions (billions?) of web pages. Disallowing that behaviour would break
> the web and we can't do that.
> Introducing new constructs that expose the same coding problems is not
> worth it - maybe we would want to change something in the future but we
> would already have been burned by existing content using this code
> It does seems like an unnecessary restriction, and with it I'll need to
> make sure that Closure Compiler doesn't introduce these when stripping
> blocks, not a big deal just one more thing to deal with.
> I was just hoping that the restriction was enabling something and not just
> On Thu, Jan 30, 2014 at 11:00 AM, Brendan Eich <brendan at mozilla.com>wrote:
>> John Barton wrote:
>>> Not silly. Can you suggest any on-line that most JS developers can
>>> understand discussing how these two forms differ?
>>> Here are some that describe them as equivalent:
>>> http://msdn.microsoft.com/en-us/library/kw1tezhk(v=vs.94).aspx <
>>> and so on across multiple languages. Whether or not you think these
>>> forms should be different, programmers don't expect them to differ.
>> This is all beside the point, since the unbraced let as consequent of if
>> cannot make a useful binding (if you use comma-separated multiple
>> declarators, you still can't use any of the values that initialize the
>> bindings except in later useless-outside-the-single-declaration
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