> Le 21 août 2018 à 21:20, Herbert Vojčík <[email protected]> a écrit :
>
> Hi!
>
> It would be nice to know if do expressions have some a chance, otherwise some
> other syntax for let-in would be really helpful, especially now that we have
> arrow functions.
>
> I would propose to use different variant of let (maybe also const):
>
> OP 1:
>
> let in a = b(), if (a) a.c();
>
> OP 2:
>
> let in a = b(), if (a) c(a);
>
> Instead of
> const big = raw => {
> let cooked = cook(raw);
> return consumer => {
> // do things with consumer and cooked
> };
> };
>
> const big = raw =>
> let in cooked = cook(raw), consume => {
> // do things with consumer and cooked
> };
>
> In short,
>
> let in binding = expr, stmt|expr
>
> It may work for `const in` as well.
>
> Herby
>
> P.S.: Alternative syntax is "let a=3, b=4, ..., in foo(a,b,c,d)" but this can
> only tell late if it is plain let-up-to-end-of-scope or local-scope-let, so
> not sure if that may be a problem; OTOH you can chain more of them and
> resembles classical let-in better.
Please, don’t take it too seriously: but have you thought about resuscitating
the (in)famous `with` statement?
```js
const big = raw =>
do with ({cooked: cook(raw)})
consumer => {
// do things with consumer and cooked
};;
```
And no the two ”;”s are not a typo: I need to end both the `with` statement and
the `const` declaration.
But more seriously... those sorts of “clever” syntaxes (`let-in` or `do-with`
or whatever), apart from complicating the language, are in danger of raising as
much issues than they’re resolving; the double-semicolon oddity is one of them.
—Claude
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