Re: undefined values in dictionaries

On 6/11/13 11:28 PM, Rik Cabanier wrote:
> You've told me that dictionary members are optional by default [1]. Why
> does their IDL have '?' for most entries? Isn't that implied since every
> entry is optional anyway?

Consider these two dictionaries:

   dictionary Foo1 {
     DOMString member;
   };

   dictionary Foo2 {
     DOMString? member;
   };

and this object being converted to those dictionary types: { member: 
undefined }.

Foo1 will produce { member: "undefined" } while Foo2 will produce { 
member: null }.

Similarly, for { member: null }, Foo1 will produce { member: "null" } 
while Foo2 will produce { member: null }.

This has nothing to do with the fact that having "member" is optional; 
that just affects what happens when an object that does not have a 
"member" property is involved.

-Boris