ES6 spec: `export default` HoistableDeclaration

[Allen Wirfs-Brock]

On Nov 19, 2014, at 1:59 PM, Axel Rauschmayer <axel at rauschma.de> wrote:

>>> * Do these grammar rules mean that you have to put anonymous function expressions in parentheses? Is that desirable (given that it’s a frequent use case)?
>> 
>> No, HoistableDeclaration[Default] includes FunctionDeclaration that lacks a BindingIdentifier.
> 
> OK, I take it the following wasn’t viable?

that’s correct.  We wanted the initialization of a function like:
    export default function () {}
to be hoisted, just like:
    export function f() {};

> 
> > `export default` [lookahead ≠ `function (` ] HoistableDeclaration  
> > `export default` AssignmentExpression `;`
> 
>>> * If the purpose of the first rule is to enable default-exporting of declarations (= no semicolon) – shouldn’t classes be included?
>> 
>> It has nothing to do with semicolons. It's so a function that is a default export can also have a local name binding.

anything that has an AssignmentExpression as its trailing grammar element needs to end with a semicolon.
> 
> Ah, interesting and useful.
> 
>> We should also allow:
>>    export default class Foo {};
>> 
>> where Foo is a module local binding.
> 
> Without the semicolon, though? The “operand” of `export default` is also a declaration, right?
right, ClassDeclaration doesn’t need to end of a semicolon.

> 
>> Please file a bug.
> 
> Will do, once I fully understand the issue.
> 
> -- 
> Dr. Axel Rauschmayer
> axel at rauschma.de
> rauschma.de
> 
> 
> 

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