Code gen when using dashes in filename

[ratmice]

I'm uncertain whether or not this is a new issue/regression caused by the changes to the codegen to use the quote library.

The grammar given in #473 if you try to run through the CTParserBuilder, you need to rename or provide a different module name, I'm pretty sure that it is trying to generate mod postgres-16-naked_y
and thus is complaining that the dashes don't form a valid ident.

My current workaround was just to rename the file. One option might be to replace dashes with underscores, or is this working as intended?

  thread 'main' (4058495) panicked at ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/quote-1.0.43/src/runtime.rs:458:9:
  "postgresql-16-naked_y" is not a valid Ident
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[ltratt]

I think a blacklist policy for characters is an endless slog with Unicode. I think we have two fundamental choices with whitelisting characters (basically [a-z0-9_]):

1. Replace every non-matching character with (say) _ to somewhat preserve uniqueness. That would still mean that a-b and a*b would both map to a_b but it's better than nothing.
2. Replace every non-matching character with its hex Unicode equivalent. This doesn't quite guarantee uniqueness, but it's somewhat closer to doing so -- but it leads to some definite ugliness.

FWIW, I'd probably do (1): it'll be good enough for 99.99% of users.

[ratmice]

I believe from https://rust-lang.github.io/rfcs/2457-non-ascii-idents.html uses https://unicode.org/reports/tr31/

If so, that would make a whitelist pretty easy, it gives a well specified set of characters for identifiers, and it seems that there should also be regex patterns \p{XID_Start} and \p{XID_Continue} for the initial character in an ident (XID_Start) and rest (XID_Continue) of the identifier.

So I think that could make a blacklist/whitelist approach viable, giving it a nice error for things that don't match, or do match a negated regex?

[ltratt]

That sounds good to me!