Function attributes

[pkolaczk]

I noticed the parser parses function attributes:

#[load(iterations = 1)]
pub async fn load(db, i) {
}

19 │ #[load(iterations = 1)]
   │ ^^^^^^^^^^^^^^^^^^^^^^^ unrecognized function attribute

Is there a way to define them to make them recognized? I'd like to be able to provide some metadata in the embedded rune script that would be read by the host app.

[udoprog]

Is there a way to define them to make them recognized?

Not at the moment. There's currently no hook to perform custom processing but all of it has to happen by the compiler.

[tgolsson]

I think there's two workflows to this: proc-macro like attributes, and information for the host. I'm wondering whether having a builtin #[meta(tag, key=value, ...)] could be enough for most things in the second group?

And then being some way of both querying for all things with a meta key, and some way of getting a specific function's meta... I guess it'd be a bit awkward in the above example, would need #[meta(load, iterations = 1)]; ... Unless we let LHS and RHS be anything that can be made a (const) value.

[jasal82]

+1

[jbrd]

I'd also find this feature really useful, for the second workflow stated above (information for the host), because it would provide a mechanism by which Rune script could advertise certain functions as being available to the host (provided the host also has a means of iterating them)