Ranges

Isiah Meadows isiahmeadows at gmail.com
Thu Nov 3 17:24:48 UTC 2016


If string ranges are based on character codes, it will (for the Latin
alphabet, at least, not necessarily for other languages).

I would prefer a function over syntax, though, since it would be more
easily adopted (polyfill > syntax), and it would fit more idiomatically
with the rest of the language (which also uses functions for most
utilities).

Maybe a `Number.range` would work?

```js
Number.range = function *range(start, end=undefined, step=1) {
  if (end === undefined) [start, end] = [0, start];
  if (end === undefined) end = Infinity;
  for (let i = 0; i < end; i += step) {
    yield i;
  }
};
```

On Thu, Nov 3, 2016, 12:56 kdex <kdex at kdex.de> wrote:

> Agreed. There's no reason why `Array.range` or `[1..10]` couldn't just
> return a generator
> or at least something that extends a generator, though. I wonder if it's
> viable to implement
> something akin to `.length` on ranges, which could be natural numbers or
> `Infinity`.
>
> As for numbers, I don't see any issues. One issue that came up in the
> original thread was
> that string ranges may need a better definition, as ["A".."C"] might not
> necessarily transpile
> to be a generator that yields "A", "B" and "C".
>
> On Thursday, November 3, 2016 4:46:03 PM CET Isiah Meadows wrote:
> > I'll note, just for clarity, that Scala's `1 to 10` is technically just a
> > normal method call equivalent to `(1).to(10)`, with optional parentheses
> > removed.
> >
> > Also, I'd prefer this to be a generator instead, so infinite ranges are
> > also possible, and so it doesn't have to be eager.
> >
> > On Thu, Nov 3, 2016, 11:52 Hikaru Nakashima <oao.hikaru.oao at gmail.com>
> > wrote:
> >
> > > How about this
> > >
> > > ```
> > > for ( i of Array.range(1, 10) ) { ... }
> > > // OR
> > > for ( i of [1..10] )  { ... }
> > > ```
> > >
> > >
> > > _______________________________________________
> > > es-discuss mailing list
> > > es-discuss at mozilla.org
> > > https://mail.mozilla.org/listinfo/es-discuss
> > >
> >
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