Feedback Thread: DIP 1029--Add throw as Function Attribute--Final Review

[Petar]

On Tuesday, 5 May 2020 at 14:39:24 UTC, Petar Kirov [ZombineDev] 
wrote:
> On Tuesday, 5 May 2020 at 08:55:58 UTC, Walter Bright wrote:
>> On 4/17/2020 6:03 AM, Tove wrote:
>>> I like it, but would prefer:
>>> throw!bool
>>> 
>>> 1) makes meta-programming easier
>>> 2) would allow deprecating nothrow (in very long term)
>>> 3) there is precedence in C++ 'noexcept(expression)'
>>> (even if they made the wrong choice with using the negated 
>>> specifier)
>>> 
>>> Any arguments against?
>>
>> throw!bool implies it is throwing a bool. Besides, with 
>> throw/nothrow we already have the full functionality.
>
> Are you saying that the following will work:
>
>     mixin(doThrow? "throw" : "nothrow")
>     void func(bool doThrow)()
>     {
>     }
>
> ?
>
> Otherwise, I'd say that the best solution, which I think Andrei 
> agreed with [1] is `attribute(true)` and `attribute(false)` or 
> more generally: `attribute(boolExpr)`.
>
> [1]: https://forum.dlang.org/post/mknspb$1dgl$1@digitalmars.com

An alternative proposal would be to merge the built-in function 
attributes `pure`, `nothrow`, `@nogc` and 
`@safe`/`@trusted`/`@system` with compiler-recognized UDAs in the 
language, like [2], as proposed by multiple people:

- https://forum.dlang.org/post/lo2avr$2hgo$1@digitalmars.com
- https://github.com/dlang/DIPs/blob/master/DIPs/other/DIP1012.md

Honestly, I think this is the best way to go, and everything else 
is a waste of time.

[2]: 
https://github.com/dlang/druntime/blob/master/src/core/attribute.d