ES3.1: Draft 1

[Maciej Stachowiak]

On May 28, 2008, at 10:38 PM, Pratap Lakshman (VJ#SDK) wrote:

> I have uploaded to the wiki (link, see bottom of the page) a first  
> draft of the specification for ES3.1. This is in the form of in- 
> place edits and markups to the ES3 specification. As you will notice  
> when reading through, there are still some open issues, and details  
> on a few features to be filled in. This spec shall be updated as we  
> make progress on these.
>

I have only skimmed the beginning of the document. The following  
change seems like a technical error:

"All constructors are objects, but not all objects are constructors."
   -->
"All constructors are functions, but not all functions are usefully  
treated as constructors."

ECMAScript constructors need not be functions; an object may implement  
the [[Construct]] internal property without also implementing the  
[[Call]] internal property, thus it would be a constructor but not a  
function. I assume it was not the intent to deliberately remove this  
possibility.

Also, the addition of "usefully treated as" does not make sense. An  
object that does not implement the [[Construct]] internal property is  
not a constructor at all, rather than merely "not usefully treated as"  
a constructor.

The definition from the original spec that actually seems wrong is in  
4.3.4, "A constructor is a Function object that creates and  
initialises objects."


With a lot of the changes, I could not tell if the intent was to  
change language semantics or to make a clarifying editorial change.


Regards,
Maciej

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