typeof symbol (Was: Sept 19 TC39 Meeting Notes)

[Brendan Eich]

Matthew Robb wrote:
> What if the semantics were fixed specifically with egal operators?
>
> if ( typeof null is "null" )

Not sure what you're saying here -- was your message cut off?

We're probably not adding 'is' and 'isnt' operators with restricted 
productions (no Line Terminator to left). Object.sameValue as 
polyfillable API is enough. But this doesn't change a thing about ==, 
=== and typeof.

/be

>
> On Sat, Sep 29, 2012 at 7:12 PM, Brendan Eich <brendan at mozilla.org 
> <mailto:brendan at mozilla.org>> wrote:
>
>     You may have missed the 1JS and typeof null messages. We cannot
>     remove "function" or make any other such backward-incompatible
>     change. But we could add new results.
>
>     The problem with instanceof is that it fails cross frame.
>
>     The invariant two-way implication relating == and === that I gave
>     is important, and for value objects such as int64 and uint64 I
>     argue it implies new typeof results.
>
>     /be
>
>     On Sep 29, 2012, at 3:46 PM, "Uli Riehm" <uli.riehm at metadea.de
>     <mailto:uli.riehm at metadea.de>> wrote:
>
>     > I think typeof should be simplified, focusing more on
>     instanceof: typeof should only return "undefined", "string",
>     "number", "boolean" and "object".
>     >
>     > var fn = function () { };
>     > fn instanceof Function // true
>     > fn instanceof Object // true
>     >
>     > Because typeof returns a string it is never true for two
>     different types, so instanceof is more detailed. Problems would be
>     that Null, NotANumber, Infinity habe to be functions, so that a
>     null can also be instanceof an Object and a NaN instanceof
>     NotANumber Number Object. Using an Int64 Function where the
>     prototype is Number, we could also have an instanceof Int64 Number
>     Object.
>     >
>     > I'm also tweaking around instanceof in my article on
>     http://metadea.de/V/default.aspx#V_construct_and_your_class ...
>     please see how I'm creating 'class' functions, having real OOP in
>     jS, using instanceof, featuring reflection using a V.Construction
>     Object class info (that is also used for prototyping a base
>     function) and an the implicit instanceOf and constructionOf
>     functions. Without hacking around __proto__ .
>     >
>     > However I'd like to say that in the part of "Why javaScript
>     typeof operator should be deprecated" I didn't thought properly
>     about primitives and the usage of the operators that my idea would
>     completely break ;) So please read that part with this warning in
>     mind, but there are also some thoughts on primitives that are
>     boxed to Object.
>     > To say simple what I need to change in the ...deprecated... part
>     is, that typeof and primitives should keep, but the constructor
>     and the primitives corresponding Object instances should be the
>     way described.
>     >
>     > Uli
>     >
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>
> -- 
> - Matthew Robb
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