FWIW: I’ve blogged about this.
http://www.2ality.com/2011/10/enums.html
On Oct 3, 2011, at 19:03 , Allen Wirfs-Brock wrote:
> Channeling for MarkM, if you use regular objects for the enumeration element
> values you probably will want to freeze them all so they can't be used as a
> communications channel.
>
> You may also want to define them with a null [[Prototype]]. I intended to do
> that for e in my original formulation for it got lost along the way from my
> mind to my finders. For debugging output you might want to capture the
> string of each numeration element value and provide a toString method.
>
> Allen
>
>
> On Oct 3, 2011, at 2:28 AM, Axel Rauschmayer wrote:
>
>> Nice one!
>>
>> It doesn’t even have to be Name.create() – new Object() works just fine. And
>> you can use switch with this pattern (I ES5-ified the code):
>>
>> function Enum() {
>> let e = {};
>> Array.prototype.forEach.call(arguments,
>> function(name) {
>> e[name] = new Object();
>> });
>> return Object.freeze(e);
>> }
>>
>> var color = Enum("red", "green", "blue");
>> var c = color.green;
>> switch(c) {
>> case color.red:
>> alert("red");
>> break;
>> case color.green:
>> alert("green");
>> break;
>> }
>>
>>
>> On Oct 3, 2011, at 1:44 , Allen Wirfs-Brock wrote:
>>
>>>
>>> On Sep 30, 2011, at 7:33 PM, Dean Landolt wrote:
>>>
>>>>
>>>>
>>>> On Fri, Sep 30, 2011 at 10:13 PM, Axel Rauschmayer <[email protected]>
>>>> wrote:
>>>> One language feature from JavaScript that I miss are enums. Would it make
>>>> sense to have something similar for ECMAScript, e.g. via
>>>> Lisp-style/Smalltalk-style symbols plus type inference? If yes, has this
>>>> been discussed already? I feel strange when I simulate symbols with
>>>> strings.
>>>>
>>>>
>>>> ISTM private name objects make a pretty nice stand-in for symbols.
>>>
>>> function Enum(...names) {
>>> let e = Object.create();
>>> names.forEach(function(n) {e[n] = Name.create()});
>>> return Object.freeze(e);
>>> }
>>>
>>> ...
>>>
>>> const colors = Enum('red,'blue','green',yellow',orange','purple');
>>> backgournd = colors.red;
>>> foreground = colors.blue;
>>> ...
>>>
>>>
>>> Allen
>>
>> --
>> Dr. Axel Rauschmayer
>> [email protected]
>> twitter.com/rauschma
>>
>> Home: rauschma.de
>> Blog: 2ality.com
>>
>
--
Dr. Axel Rauschmayer
[email protected]
home: rauschma.de
twitter: twitter.com/rauschma
blog: 2ality.com
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