On Wed, Mar 11, 2009 at 3:31 AM, David-Sarah Hopwood
<[email protected]> wrote:
> Garrett Smith wrote:
[...]
>>
>> Maciej' Function.create proposal:-
>>
>> Function.create("[Foo bar]", "param1", "param2", "code(); goes(); here();");
>>
[...]
>>
>> Possible alternative:-
>> Function.create( name, fun[, context] );
>
> I don't see the problem here that would require overriding the context.
No problem there.
The problem was with the other (Maciej') Function.create.
Function.create param |code|, as a string would be used to build a
Function. That function would have to have global scope. To use the
calling context's scope (as eval does) would be a security issue.
To *not* use the calling context's scope would not allow for wrapping
functions (Jeff Watkins' use case).
> The scope used by fun would be its original lexical scope. In the example
> above:
>
> EventPublisher.fireEvent = function(publisher) {
> return Function.create(publisher.eventName + "Handler", function(ev) {
> // code here
> // can refer to 'publisher', etc. if needed
> });
> };
>
> All the hypothetical Function.create does is to create a new function that
> behaves the same as its fun argument, but with a different name. The
> .name property of all function objects would be non-[[Writable]] and
> non-[[Configurable]].
>
> Whether this is actually needed, I'm not sure, but it has all of the
> functional and security properties I've seen stated as desirable so far
> in this thread.
>
I agree on both points. It is secure this way, but I am not sure if it
is needed.
If used for debugging, what would the debugger step into for:-
var f2 = Function.create("f2", fun)(0);
function fun(i) {
if(i === 0) throw Error("zero");
}
?
Garrett
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