[eeps] EEP 049: Value-Based Error Handling Mechanisms

[Loïc Hoguin]

Hello,

On 12/7/18 12:28 PM, Kenneth Lundin wrote:
>         Comments on the solution
> 
> In most of the examples where we find usage of nested case, the unwanted 
> result ({error, Reason} in this case) is not just returned, there is 
> some other actions performed as well before returning. In those cases 
> the proposed solution does not help.
> 
>   * We don't like a language construct which is hard coded to support
>     ok,{ok,Result}, {error,Reason}.
>   * the use of underscore _ <~ to mean a match with ok is not a hit, it
>     will make programs harder to read
>   * We are against the introduction of /unwrapexprs/ that cannot be used
>     everywhere where expressions are allowed.
>   * The /unwrapexpr/ changes the scoping rules and can not be used in
>     nested expressions and not outside begin ... end. 
[...]
>   * We say no to the proposed language extensions. We don't think they
>     are general enough and we also see some problems with them.
[...]

In other words a proposal that doesn't have the unwrap mechanism (and 
therefore no hard coding) would have better chances of being accepted? 
This is the only argument against it as far as I can see.

There's also "we can do it with exceptions!" but I don't think that's a 
strong argument.

Cheers,

-- 
Loïc Hoguin
https://ninenines.eu