On 3 January 2012 21:18, Brendan Eich <bren...@mozilla.com> wrote:
> On Jan 3, 2012, at 1:29 AM, Andreas Rossberg wrote:
>
>> On 3 January 2012 07:19, Brendan Eich <bren...@mozilla.com> wrote:
>>> On Jan 2, 2012, at 6:07 AM, Andreas Rossberg wrote:
>>>
>>>> In other words, I think the main points of your proposal can
>>>> essentially be rephrased to:
>>>>
>>>> 1) Rename "use version 6" to "use module".
>>>> 2) Allow module declarations in classic mode.
> [...]
>>>> 3) Make every module body start with an implicit "use module".
>>>
>>> That's not right: use module; in a pragma turns the enclosing block or body
>>> into a module {...}, in a macro-like way. Then if the module {...} is
>>> illegal in the given context (i.e., not nested immediately in another
>>> module's body), you get the same error you'd get trying to write, e.g.,
>>>
>>> if (cond) { module { /* stuff */ } }
>>
>> Hm, I don't follow. How is this related to point (3)? The body of a
>> module always is a context where module declarations are allowed.
>
> Your (3) seemed to say "use module" was something distinct from (and also
> implicit in, so a part but not the whole of what is declared by) module
> declaration syntax. It's not -- as proposed, it's an alternative to explicit
> anonymous module{...} bracketing syntax that translates the block or body
> enclosing the pragma to an anonymous module.
Yes, I understand that. My point was that you can reformulate all
that, for (almost) equivalent effect, by saying that "use module" is
_not_ a module definition, but basically the same mode pragma as
before, except that it now is implicit with every module body.
The only difference I can see with this description is its effect on
the semantics of multi-part scripts.
>>>> 4) Keep the semantics of the top-level scope unaltered, even in
>>>> presence of a top-level "use module".
>>>
>>> No, see above: that turns the verbatim top level into the ... part of
>>> module {...}.
>>
>> OK, I see, but then we effectively have opted out of the global
>> object, at least as a carrier for the verbatim top-level declarations
>> of the (current) script, haven't we?
>
> No. Dave wrote "Short answer: giving up" and "You can still do it with a
> custom loader".
>
> That is, even in a module (declared at top level either implicitly via the
> |use module;| pragma or explicitly via module id? {...}), the proposal still
> keeps the global object on the scope chain. But the proposal does a free
> variable analysis based on importing the properties of the global at the
> start of the module's body, and any free variables are early errors.
Those quotes from Dave's post are exactly the bits I couldn't make
sense of properly. Because even before his proposal, I remember what
you describe being an option we were still considering. Thanks for
clarifying.
/Andreas
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