Value Type Exceptions

[Richard (Rikki) Andrew Cattermole]

On 22/09/2024 10:25 PM, IchorDev wrote:
> On Thursday, 19 September 2024 at 18:31:02 UTC, Richard (Rikki) Andrew 
> Cattermole wrote:
>> - Did I mention the throw set is inferred? Sadly it cannot shrink down 
>> to the empty set due to virtual functions/function pointers, but we 
>> could change that with an edition if it's desirable to do so.
>>
>> ```d
>> int toCall() @throw(:FailedToDecodeUTF) {
>>     throw :FailedToDecodeUTF;
>> }
>>
>> int caller() /* @throw() */ {
>>     int result;
>>
>>     try {
>>         result = toCall();
>>     } catch(:FailedToDecodeUTF) {
>>         result = 0xDEADBEEF;
>>     }
>>
>>     return result;
>> }
>> ```
> 
> But if `caller` is manually marked nothrow then it wouldn’t be a 
> compiler error anymore just because you didn’t catch `Exception`?

``nothrow`` is equivalent to the empty set ``@throw()``, so in the 
example it is ``nothrow``.

So I'm not sure what you are asking?

> Also, could you elaborate on what `:FailedToDecodeUTF` is in this 
> situation? Like, what exactly is it a member of?

The sumtype that represents the exceptions, specifically a tag that has 
no payload.

See my sumtype proposal, this would use that under the hood.