Binary data (ByteArray/ByteVector) proposal on public-script-coord

[Alex Russell]

On Nov 5, 2009, at 11:03 PM, David-Sarah Hopwood wrote:

> Oliver Hunt wrote:
>> On Nov 5, 2009, at 10:14 PM, David-Sarah Hopwood wrote:
>>> Oliver Hunt wrote:
>>>> I disagree here -- i believe mutable vs. immutable data is  
>>>> different
>>>> from unfrozen and frozen objects [...]
>>>
>>> Why? What would the hypothetical Data.prototype.freeze do that  
>>> would be
>>> different to applying Object.freeze to a Data object?
>>>
>>>> (though i agree that the function names
>>>> freeze and frozen are just asking for problems in conjunction  
>>>> with ES5
>>>> :D ).  There are plenty of times where I would want to provide  
>>>> immutable
>>>> data (the UA sharing content, etc), but i may still want to  
>>>> modify the
>>>> object itself.
>>>
>>> Oh, you mean that you want *read-only* Data objects backed by a  
>>> mutable
>>> array. That is not the same thing as an immutable (or "frozen") Data
>>> object.
>>
>> No, the issue here is that Charles has conflated object freezing with
>> immutable data,
>
> That isn't conflation; they're the same.
>
>> frozen objects and immutable data are not the same thing
>
> You are mistaken. This is a case where terminology across languages is
> quite consistent, and is as I've described it. "Frozen" means  
> exactly the
> same thing as "immutable", and implies that the state of the object  
> will
> never be observed to change [*]. An object is "read-only" if there  
> is no
> means to directly change its state via a reference to it, which does  
> not
> necessarily imply that its state cannot be observed to change.
>
>> -- for instance in the DOM I cannot set indices of a NodeList, but  
>> the
>> NodeList does not need to be frozen.
>
> NodeList objects are read-only.

This is an artifact of the way they can be created today (no exposed  
ctor for them, no exposed prototype, only alien functions can generate  
them, etc.). It should not be held up as a desireable design point or  
a counter to something else. Mutable NodeList's which implement Array  
semantics and mutability would be extremely useful.

Regards

> [*] It is ambiguous whether indirectly referenced state can change; if
>    it is important that it cannot, say "deep-frozen" or "deeply  
> immutable".
>
> -- 
> David-Sarah Hopwood  ⚥  http://davidsarah.livejournal.com
>
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--
Alex Russell
slightlyoff at google.com
alex at dojotoolkit.org BE03 E88D EABB 2116 CC49 8259 CF78 E242 59C3 9723