[Laszlo-user] proposal for new behavior of compiler when declaring child nodes with same name as attributes

[jamesr]

It's not that I disagree with the proposal, but in a way I mourn the  
passing of simpler namespacing. It seems like the orthgonal namespaces  
increase complexity of the run time, and part of me wants to see that  
complexity managed by framework authors - i.e. using prefixed names  
for reserved words so that layout becomes lzLayout. It's not that the  
proposal is bad from a CS standpoint, but that it steepens the  
learning curve of how laszlo works. It seems to me that telling people  
that what names you see from inspecting a node is what populates your  
namespace (like a typical object), not that some conflict and some  
don't based on an implementation you don't see.

However this is just philosophy and not pragmatism. If this proposed  
feature works stably and doesn't cause problems, it's hard to argue  
against it.

-j

On Jun 2, 2008, at 8:38 AM, P T Withington wrote:

> I think this is a good proposal, since it should actually be pretty  
> rare that you want to declare an attribute that ends up being one of  
> your child nodes.
>
> On 2008-05-28, at 13:24 EDT, Henry Minsky wrote
>
>> Sorry my message got cut off before I could finish it:
>>
>> This is a proposal in response to this bug, which came up when  
>> someone named
>> a child view "layout", and got
>> unexpected results in a view.
>>
>> http://jira.openlaszlo.org/jira/browse/LPP-5799
>>
>> The current compiler behavior is that it will allow you to declare  
>> a child
>> with the same name as an attribute,
>> as long as the attribute has a null default value. This unfortunately
>> applies to virtually every attribute
>> declared in the schema, so in practice you can easily shadow all  
>> sorts of
>> important properties in
>> a view or node, by naming a child view with the same name as a class
>> attribute, with no warning from the compiler.
>>
>> This proposal is that we add a new LZX attribute type, "node",  
>> which you can
>> use to declare that
>> an attribute name can have the same name as child node.
>>
>> So for example you could have
>>
>> <class name="myclass">
>>  <attribute name="titleview" type="node"/>
>>
>>  <handler name="oninit">
>>      this.titleview.setAttribute('bgcolor', 0xcccccc);
>>  </handler>
>> </class>
>>
>> Then elsewhere you could say
>>
>> <myclass>
>>    <view name="titleview">
>>      ....
>>   </myclass>
>>
>> And the compiler would not complain.
>>
>> The existing compiler  behavior would be changed so that for any  
>> attribute
>> type
>> except "node",  if you name a child node
>> with the same name as that  attribute, you get a compiler warning,
>> regardless of
>> whether the attribute was declared with a default value.
>>
>>
>>
>> Henry Minsky
>> Software Architect
>> hminsky at laszlosystems.com
>

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