An Introduction to JS-Ctypes

[Brendan Eich]

On Sep 18, 2011, at 12:09 PM, Andrea Giammarchi wrote:

> I know it's the same, for this reason I said it was "shimmable"
> 
> New syntax would be fine as long as minifiers won't break everything so ... as long as minifiers are compatible, but this is an extra story I guess, also it's not fundamental it's just nicer addiction since many libs are using single object as function argument to obtain similar behavior
> 
> fn({a: 1, b: 2})
> 
> and back to the "too many objects created due lack of defaults/named arguments" trap ...

For this style of parameter-object passing, ES6 destructuring helps. The fn function would be declared:

function fn({a, b}) {...}

This is already supported in SpiderMonkey in Firefox, but ES6 adds a feature wanted for defaulting missing properties:

function fn({a = 1, b = 2}) {...}

(long-hand is function fn({a: a = 1, b: b = 2}) {...}).

That way you can call fn({a: 3}) or fn({b: 4}) and have the missing property filled in with its default value.

Optimizing implementations can avoid creating the object passed as an actual parameter by specializing when inlining or caching.

This parameter-object style is already popular. With destructuring + parameter default values, it tends to take away the motivation for keyword parameters of the kind you sought.


> Never mind, this is not for this thread.

It's ok, we can change the subject if necessary to fork a sub-thread.

/be


> 
> Best Regards,
>     Andrea Giammarchi
> 
> 
> On Sun, Sep 18, 2011 at 3:14 PM, Brendan Eich <brendan at mozilla.com> wrote:
> On Sep 18, 2011, at 5:07 AM, Andrea Giammarchi wrote:
> 
>> On Sun, Sep 18, 2011 at 7:17 AM, Brendan Eich <brendan at mozilla.com> wrote:
>> 
>> The point is that you don't *have* to pass a fresh object literal to each constructor call.
>> 
>> /be
>> 
>> 
>> I know Brendan, my point is that I can predict devs will do every time .... we'll see
>> 
>> Thanks for other reply, I thought named arguments where proposed tho ... any chance we can discuss this somehow ? ( not here )
> 
> Can't use =, that is just the assignment operator, so
> 
>   foo(a = 1, b = 2)
> 
> is the same as
> 
>   (a = 1, b = 2, foo(a, b))
> 
> We'd need some new operator or punctuator, e.g.
> 
>   foo(a: 1, b: 2)
> 
> or
> 
>   foo(a => 1, b => 2) // clashes with arrow function syntax
> 
> Anyway, this only helps for the "top ply" of the object/array tree containing values to store as binary data. You'd still have object and array literals starting one ply down.
> 
> /be
> 
> 
> 
> 

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