Improving ECMAScript as a compilation target

[Brendan Eich]

Two open issues remain:

On May 4, 2009, at 6:20 PM, Allen Wirfs-Brock wrote:

> In the function defined for the example's invoke item the first  
> argument to apply probably should be obj rather than peer.

Possibly, but in the example peer[id] may be a function that insists  
on |this| being bound to peer, not obj. If the function is pure, the  
arguments flow in and a result comes back, and the catchall delegates  
without mutating peer or obj. If the function mutates |this|, then the  
effects can be recovered by calling other methods, or by property  
access, which again is delegated without a wrapper.


> I would be inclined to specify an additional argument (probably the  
> first) for each handler function that would be passed the "this"  
> value. Closure capture like is done in the example works but my  
> intuition is that there will be situations where it would be handy  
> to use the same catch-all descriptor for several objects.

Agreed, but why not use |this| instead of an extra (leading) parameter?

/be