'function *' is not mandatory

Yuichi Nishiwaki yuichi.nishiwaki at gmail.com
Sat Aug 31 13:14:39 PDT 2013


OK, right. I understand my first propose does not work. :-|
So one more question is how about making '*' optional in strict mode?
(Should I separate the topic to another?)

2013/9/1 Brendan Eich <brendan at mozilla.com>:
> Let's not go in circles -- the primary reason for function* is because yield
> is not reserved in JS and is used by web content as a plain identifier. It
> is a low-precedence unary prefix operator, so cannot be contextually
> reserved by a grammatical restriction as "module" can. It needs opt-in
> syntax.
>
> Separately, some on TC39 want a flag on the function, in the head syntax, to
> alert readers to the generator. That's a secondary reason, independent and
> not as strong in my view.
>
> There's nothing to "get" or "not get" about backward compatbility. It just
> "is". :-|
>
> /be
>
>> Yuichi Nishiwaki <mailto:yuichi.nishiwaki at gmail.com>
>> August 31, 2013 12:55 PM
>>
>> I can't get the point, why you need to know if the function is a
>> generator or not at a glance?
>>
>> 1. Forcing users to mark the function as a generator is only a
>> duplication. It basically doesn't have any meaning other than
>> double-checking, and fundamental risk for the unintentional creation
>> is still not removed.
>> 2. Even if you know the function is a generator in early, you still
>> need to read the entire source code to get the information about what
>> the generator yields and when it stops.
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>> es-discuss at mozilla.org
>> https://mail.mozilla.org/listinfo/es-discuss
>>
>> Oliver Hunt <mailto:oliver at apple.com>
>> August 31, 2013 12:25 PM
>>
>> On Aug 31, 2013, at 12:15 PM, Yuichi Nishiwaki<yuichi.nishiwaki at gmail.com>
>> wrote:
>>
>>> Hi all, I just found a post that the current generator syntax
>>> (function *) seems have decided in:
>>>
>>> https://mail.mozilla.org/pipermail/es-discuss/2011-July/015799.html
>>>
>>> According to the post, the biggest reason the star syntax is adopted
>>> for now is that you cannot write empty generators with star-less
>>> functions in a consistent simple way. But the situation has changed,
>>> and in the current spec (rev 17) yield* is now capable of taking any
>>> kind of iterator, so you can make empty generators just like
>>>
>>> ```js
>>> function * () {
>>>     yield * [];
>>> }
>>> ```
>>>
>>> This looks enough good and simple at least to me. And I wonder if even
>>> now generators still need to be declared with 'star's. What are the
>>> advantages of 'star'ed generators rather than 'star'-lesses? If not
>>> exist, shouldn't it be removed (for the simplicity)?
>>>
>>
>> The reason for the * is substantially (IIRC) to make it possible for an
>> engine
>> to help prevent developers from unintentionally creating a generator
>> function,
>> and to make it possible for someone attempting to use a function to
>> identify immediately
>> whether it is a generator or a regular function.
>>
>> --Oliver
>>
>>> Thank you.
>>>
>>> --
>>> Yuichi Nishiwaki
>>> _______________________________________________
>>> es-discuss mailing list
>>> es-discuss at mozilla.org
>>> https://mail.mozilla.org/listinfo/es-discuss
>>
>>
>> _______________________________________________
>> es-discuss mailing list
>> es-discuss at mozilla.org
>> https://mail.mozilla.org/listinfo/es-discuss
>>
>> Yuichi Nishiwaki <mailto:yuichi.nishiwaki at gmail.com>
>> August 31, 2013 12:15 PM
>>
>> Hi all, I just found a post that the current generator syntax
>> (function *) seems have decided in:
>>
>> https://mail.mozilla.org/pipermail/es-discuss/2011-July/015799.html
>>
>> According to the post, the biggest reason the star syntax is adopted
>> for now is that you cannot write empty generators with star-less
>> functions in a consistent simple way. But the situation has changed,
>> and in the current spec (rev 17) yield* is now capable of taking any
>> kind of iterator, so you can make empty generators just like
>>
>> ```js
>> function * () {
>> yield * [];
>> }
>> ```
>>
>> This looks enough good and simple at least to me. And I wonder if even
>> now generators still need to be declared with 'star's. What are the
>> advantages of 'star'ed generators rather than 'star'-lesses? If not
>> exist, shouldn't it be removed (for the simplicity)?
>>
>> Thank you.
>>
>> --
>> Yuichi Nishiwaki
>> _______________________________________________
>> es-discuss mailing list
>> es-discuss at mozilla.org
>> https://mail.mozilla.org/listinfo/es-discuss
>>
>


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