It would be simpler if Go fmt would let people write if statements on a
single line :
if file,err := os.Open(fname) ; err!=nil { return err }
Here, no need for new syntax and still readable while reducing the
conditional noise. And everybody could be happy.
Le vendredi 6 janvier 2017 01:35:14 UTC+1, xjru a écrit :
>
> Here are some examples for valid error returns according to my proposal:
>
>
> file, err := os.Open(fname) ||| return err
>
> file, err := os.Open(fname) ||| panic(err)
>
> file, err := os.Open(fname) ||| return errors.Wrap(err, "too bad")
>
>
> The third example uses the Wrap function from github.com/pkg/errors. The
> ||| operator is not important. It could be any operator, but the idea
> behind the tripple bar is to signal a special kind of or. I can imagine
> using the keyword "orr" instead.
>
> The semantics is pretty simple. If there is an (possibly multiple)
> assignment whose last component conforms to the error interface, then it
> may be followed by ||| and a single statement that must either return or
> panic.
>
> You might argue that this isn't much longer:
>
> if file, err := os.Open(fname); err != nil {
> return err
> }
>
> However, this has the unfortunate side effect of putting file into the
> scope of the if block. That's why we often have to use
>
> file, err := os.Open(fname)
> if err != nil {
> return err
> }
>
> I think my proposal has a couple of benefits.
>
> - It is perhaps not too magical (just a little bit because the
> condition is implied by the ||| operator).
> - I doesn't obscure the clear view on the assignment statement itself
> (unlike Rust's try! macro).
> - The keywords return or panic make it very clear what happens to
> control flow (unlike Rust's try! macro).
>
> It does have the drawback that it is a unique special case for errors not
> based on a more general language facility. It makes the language a little
> bit more complex. But I think errors are frequent enough to deserve a
> little bit of syntactic sugar.
>
> Apologies if this has been discussed to death.
>
>
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