Support miette::IntoDiagnostic for pest::error::Error<R>

[cgranade]

It would be nice to be able to more easily use miette to format diagnostics generated by pest errors. Currently, since pest::error::Error::message is private, this cannot easily be done by third-party libraries that depend on both pest and miette without re-implementing much of the message formatting logic in pest. It would be helpful if either message was made public, or if there was a feature-gated impl<R> IntoDiagnostic for pest::error::Error<R> to make it easier to include pest errors in miette diagnostics.

Thank you! ♥

[tomtau]

@bobbbay would you like to tackle this? You mentioned miette integration in #606 (comment)

[bobbbay]

Yes, I already experimented with this locally. A feature-gated implementation is (in my opinion) the best way to go. The issue is moreso refactoring the internal Error representation so that we can implement miette's SpanContents on pest's built-in span type.

I would love to work on this, but I'm currently on vacation and can't always be next to my laptop. If anybody would like to work on this before I get back (end of August), please do.

[gavrilikhin-d]

So what’s the status on this?

[bobbbay]

The PR is closed and I don't plan on working on this anytime soon. From an implementation standpoint, it's doable.