On Aug 17, 6:33 pm, Matt Kruse <[EMAIL PROTECTED]> wrote:
> On Aug 17, 11:11 am, Stephan Beal <[EMAIL PROTECTED]> wrote:
> > i think this would be counter-intuitive. If i pass a string to a
> > function and know that it will be executed, i would expect the string
> > to be eval()'d, not run in a Function object, and those evaluate their
> > code with different scoping rules.
>
> How so? Both are run in the context of the global object, are they
> not?
According to the rhino book:
"A last, very important point about the Function() constructor is that
the funcions is creates do not use lexical scoping; insteawd, they are
always compiled as if they were top-level functions..."
That alone completely rules out their use for many use-cases as event
handlers, which often want access to variables from their containing
scope.
> > Shouldn't that be (new Function(f)) instead of (Function(f))?
>
> Same diff, but shorter.
i don't think those are the same, as (Function(...)) is not creating a
new object, but theoretically its working directly on the prototype
object. Maybe i'm wrong on this, but it looks suspicious to me.
> > IMO this change would be far more complex that it seems because, for
> > example, the following no longer applies:
> > if( typeof f == "function" ) { ... }
>
> Why would you want to do this, anyway?
When a function takes multiple argument types you have to check what
those types are. That gets more complicated with two distinctly
different ways of having functions.
> Once it gets past the initial call to click() or whatever, it is a
> function all the way down.
> If you define a new Function, the resulting object is typeof
> 'function'.
~> SpiderApe -e "x=new Function('1');print(typeof x);"
function
You're right - i wasn't aware of that.
> There would be no visible effect anywhere else in plugins, etc.
i said earlier (in two posts) that the call syntax is different, but
that is apparently incorrect:
~> SpiderApe -e "x=new Function('print(1);');x();"
1
JS apparently offers special-case handling of this type.
> >The cascade of side-effects is enormous.
>
> I don't see any side-effect at all, but I may of course be wrong ;)
My apologies - i grossly overstated the side-effects (/me smacks
forehead). But the scoping issue is still critical, as event handlers
often need access to variables from their contained scope, and that
apparently can't be done with Function objects.
