Subj : Re: Creating classes/namespaces on the fly from existing functions?
To   : Shanti Rao
From : Brendan Eich
Date : Tue Jan 11 2005 04:06 pm

Shanti Rao wrote:
> 
>>> f = getLibrary("foo.js")
>>> includeLibrary("bar.js")
>>>
>>> With the former, there are a few minor glitches. Consider
>>>
>>> js>f = {Foo: function() {this.message = 'Foo'}};
>>
>>
>>
>> But why must getLibrary be implemented so as to use anonymous 
>> functions if "foo.js" contains named function declarations?
>>
>> /be
>>
> 
> That is exactly the problem with using an object when you really wanted 
> a namespace.
> 
> For the sake of argument, assume that "foo.js" contains a named function 
> Foo(), and getLibrary() makes Foo() (formerly a global object in foo.js) 
> into a property of an object when included in another script.


Sure, but Foo is still a named function; its name is intrinsic.  That 
preserves the invariant you seemed to want last time (a.constructor.name 
being defined).


> Now that I think about it some more, it's sufficiently confusing to 
> promote the minor glitch into a major irritation. It makes it very 
> difficult to convert a stand-along script into a library. This 
> conception of a getLibrary() function will probably be a failure.


You're right that other things break in such a case.  That's why JS2 has 
packages that you import, including things like explicit, to restrict 
the use of unqualified imported names.


> An include() function still works, so long as you don't unintentionally 
> use the same global variable name in two different source files. This 
> highlights the fact that creating a class is very different from 
> creating a namespace.


Or a package, which is like an object and a namespace, not just one or 
the other.


> Shanti
> 
> PS. Straw man: what about a 'library' as a separate thread with a 
> COM-like messaging interface? A synchronous function call would send a 
> message and wait for a reply. Or not wait. It invokes buzzwords like 
> grid computing and transaction processing.


I don't see why threads should be dragged in implicitly.

/be

.