Is there a way to obtain a list, at compile-time, of all the exception types that a function might throw (directly or through a call to another function)?

Thanks.

On Wednesday, 24 February 2021 at 19:38:53 UTC, Mark wrote:
> Is there a way to obtain a list, at compile-time, of all the exception types that a function might throw (directly or through a call to another function)?
>
> Thanks.

I don't believe that there's any built-in way, as that'd mean that functions would have to define what they throw as part of their signature (like in Java).

But you can semi-emulate it with metaprogramming, it's just that you'll have to manually keep all the information up to date.

Here's an example: https://run.dlang.io/is/UUHumO

Which supports saying what a function directly throws (`@Throws`), and also saying what functions it calls that may also throw well-defined exceptions (`@ThrowsInclude`), and results in `(Exception, MyExcept)`

On Wednesday, 24 February 2021 at 19:38:53 UTC, Mark wrote:
> Is there a way to obtain a list, at compile-time, of all the exception types that a function might throw (directly or through a call to another function)?

No, since this is not known at compile-time.

See: https://forum.dlang.org/post/qnarroejixxtqxjiwvhy@forum.dlang.org

On Wednesday, 24 February 2021 at 19:58:41 UTC, SealabJaster wrote:
> ...

Just realised that can include duplicates, but there's std.meta.NoDuplicates to solve that.

On 2/24/21 2:38 PM, Mark wrote:
> Is there a way to obtain a list, at compile-time, of all the exception types that a function might throw (directly or through a call to another function)?
> 
> Thanks.

Crazy idea:

Could a program import its own source file as a string (`string source = import('thisfile.d')`) and `-J<path>` , then use a lexer/parser to generate AST of the source code and extract exceptions potentially thrown by given functions -- all at compile  time?

You'd hit a very big wall with separate compilation unless you can inspect all the code, and know where to find it.

But you'd have a problem, for instance, if you are writing a plugin (.so / DLL) for a product for which you only have .di files.

Or even worse the other way round: if you want to allow people to write plugins for your product, you can't know what they'll throw, even if they have your code, unless you enforce a `nothrow` interface.

But I guess that if you're not doing any of this, it should be possible... although I'd still do it as a separate pre-compilation step, so it could be cached.

On 26/2/21 3:21, James Blachly wrote:
> On 2/24/21 2:38 PM, Mark wrote:
>> Is there a way to obtain a list, at compile-time, of all the exception types that a function might throw (directly or through a call to another function)?
>>
>> Thanks.
> 
> Crazy idea:
> 
> Could a program import its own source file as a string (`string source = import('thisfile.d')`) and `-J<path>` , then use a lexer/parser to generate AST of the source code and extract exceptions potentially thrown by given functions -- all at compile  time?