[x3d-public] scoping for proto names ?

[John Carlson]

Ah, forgot one thing.   You search down the stack from the top searching
for a field name.

John

On Sun, Jun 7, 2020 at 3:50 PM John Carlson <yottzumm at gmail.com> wrote:

> I learned some about scope by studying how LISP/Scheme implemented them.
> It’s like a stack of maps,  when you enter a new scope, you get a new map,
> and push it on the stack,   When you exit a scope, you pop the map.   You
> can enter new fields into the map with their values.
>
> John
>
> On Sun, Jun 7, 2020 at 3:41 PM Andreas Plesch <andreasplesch at gmail.com>
> wrote:
>
>> Let's see if I can explain this question clearly.
>>
>> First the example:
>>
>>
>> https://github.com/andreasplesch/x3dom/blob/gh-pages/test/functional/proto/castle/proto_nested.x3d
>>
>>
>> The table2 ProtoBody uses an instance of the leg2 proto. The leg2 proto
>> declaration is defined outside of the table2 proto declaration name scope.
>>
>> The expected result is that the table2 proto declaration is able to use
>> the name 'leg2' to find the leg2 proto definition.
>>
>> This does not work in my x3dom proto exploration and it took me a while
>> to realize that the reason is (too?) strict scoping. The leg2 proto
>> definition occurs outside of the execution context and name scope of the
>> table2 proto. Therefore it is not visible to the table2 proto.
>>
>> At first glance this strictness seems not unreasonable, however, all
>> tested browsers display the scene as expected.
>>
>> So I am somewhat puzzled. I think what it means is that name scoping does
>> not apply to the name of Protos given by the name attribute, since the name
>> of Proto is the name of a node definition. Proto names are possibly global.
>>
>> One consequence is that two Protos in a scene cannot have the same name.
>> And I recall that this case is spec'ed to lead to undefined behaviour.
>>
>> Would it be correct to treat Proto names as global ? To be clear, by
>> Proto name I refer to the name given by the name attribute, not a DEF name
>> of an instance.
>>
>> Thanks for any insight, or pointers to relevant spec. sections, -Andreas
>>
>> --
>> Andreas Plesch
>> Waltham, MA 02453
>> _______________________________________________
>> x3d-public mailing list
>> x3d-public at web3d.org
>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>>
>
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