feat(DeriveAttribute) Implement derive macro attribute for format

tokio-rs / valuable

MIT License

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feat(DeriveAttribute) Implement derive macro attribute for format #131

Open johnhurt opened 2 weeks ago

johnhurt commented 2 weeks ago

Build on the newly-introduced derive-attribute framework to allow fields in structs to be written to the final value as a formatted string instead of their actual value. This allows for types that don't (and can't or won't) implement Valuable to be included in the value

taiki-e commented 1 week ago

Thanks for the PR!

This appears to bypass #43 well, which is interesting.
This currently requires allocation, which is unfortunate given that there are APIs such as format_args that do not require allocation.

johnhurt commented 5 days ago

Ooooooh, I see what you mean. Let me tackle those one at a time

That doesn't seem like a good thing. I didn't think about the ability to leak things out with a format. I will change this from #[valuable(format = "{}")] to just #[valuable(debug)] to avoid
There doesn't seem to be a way around allocating to do what I'm trying to do. Even to complete #4 I think would require allocation :-/ ... Would you be open to the idea of adding an opt-in alloc feature that would gate the #[valuable(debug)] attribute?

taiki-e commented 8 hours ago

Adding Debug/Display (or Debugable/Displayable mentioned in https://github.com/tokio-rs/valuable/issues/43#issuecomment-854111197) variant to valuable::Value and then adding #[valuable(debug)]/#[valuable(display)] that pass the field as Value::Debug/Value::Display to derive seem to good idea to me.