Nullablity

Brendan Eich brendan at mozilla.org
Wed Jun 21 10:07:54 PDT 2006


On Jun 21, 2006, at 12:27 PM, John Cowan wrote:

> Brendan Eich scripsit:
>
>> 1.  Mindshare from Java, C#, and other languages that include null
>> among the values of reference types.
>
> This argument is strong but not overriding.

Agreed.

>> 2.   The difficulty of initializing variables of non-nullable type
>> with a sound default value.
>
> At the syntax level this can be solved by not allowing such variable
> declarations.  At the semantic level it's much deeper, and may justify
> some language support for the Null Object pattern.  Statically typed
> functional languages typically have a distinct variety of null for
> each nullable type, and I think rightly so.

Agreed, but ES4 is not a statically typed language by default.  The  
type checker used in the strict mode is optional to programmers as  
well as to implementors; we're writing a normative specification for  
it to ensure interoperation.

/be




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