Re: "x.constructor == Foo" vs "x instanceof Foo"

Thomas 'PointedEars' Lahn <PointedEars@xxxxxx> writes:

function a() { alert("First") }

function b() { a() };

function a() { alert("Second") }

b();

The second declaration for `a' overwrites the reference with one to another
Function object before b() is executed. ISTM you have just proved that
there is a closure :)

I expected that reply and have prepared the following, demonstrating
that the lookup of a() in b() is done via dynamic, not lexical scoping.

function a() { alert("first") }

function b() { a() }

c = { a: function() { alert("second") } };
a();

with (c) {
a();
}

every function that calls another function,
Not every function. It depends on where the other function was defined.

See code above. We're accessing a global property, not a lexical
variable. The fact that the variable is a function doesn't matter.

That seems contradictory.

Javascript variables that aren't declared (with var) in a function scope
or as a function argument are dynamic, defaulting to the global object's
property via whatever with() scopes are in place.

The same goes for functions: named functions defined in the global scope
are set as dynamic variables. Named functions defined within a with(X)
in the global scope are put in X. Named functions defined within a
function scope are lexical. I'm not sure what with() within a function
does.

Compare the above with:

function a() {
alert("first");
}

function b() { a() }

function c() {
function a() {
alert("second");
};
b();
}

a();
c();


or accesses any other global property would be a closure:
[...]
That is correct. Probably that is why Flanagan made his oversimplifying
false statement.

Which statement?

That one cited in
<bc992427-bf06-4308-8416-b82396340578@xxxxxxxxxxxxxxxxxxxxxxxxxx>

Different thread, same source of confusion. Sigh. [psf 10.1]

I don't see the connection.

Joost.
.

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