Merge #16

16: Proof-of-concept SyntaxKind as enum r=matklad a=CAD97

This was the one bit about the original RFC I was most confused about. Why isn't `SyntaxKind` a normal `enum`?

If it's to signify that it's non-exhaustive [`#[non_exhaustive]`](https://github.com/rust-lang/rust/issues/44109) should be used. (Or `#[doc(hidden)] __Nonexhaustive` on stable.)

If it's so that more variants can be added externally, why? There's no need for that, that I can foresee.

If it's to expose the `SyntaxKind` type but not any of its instances, why? This is the only actual benefit I can see of this pseudo-enum style.

This diff is meant to be as non-invasive as possible, and as such reexports all symbols as they existed prior to this. It's diffed on top of the assumed-good-to-merge #15 to avoid the conflict between them.

Diff without #15: <https://github.com/matklad/libsyntax2/pull/16/commits/4244948c6b1a62bd0e1ef276d1f0cc22c36f6f66>
Just `src/syntax_kinds.rs`: <https://github.com/matklad/libsyntax2/pull/16/commits/4244948c6b1a62bd0e1ef276d1f0cc22c36f6f66#diff-8f0d69eb4fe0148851505f787b6fd3bb>

1 files changed, 1 insertions, 20 deletions

diff --git a/src/tree/mod.rs b/src/tree/mod.rs
index aaf048c73..43bda480d 100644
--- a/src/tree/mod.rs
+++ b/src/tree/mod.rs
@@ -1,5 +1,4 @@
 use text::{TextRange, TextUnit};
-use syntax_kinds::syntax_info;
 
 use std::fmt;
 use std::cmp;
@@ -7,25 +6,7 @@ use std::cmp;
 mod file_builder;
 pub use self::file_builder::{FileBuilder, Sink};
 
-/// The kind of syntax node, e.g. `IDENT`, `USE_KW`, or `STRUCT_DEF`.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct SyntaxKind(pub(crate) u32);
-
-pub(crate) const EOF: SyntaxKind = SyntaxKind(!0);
-pub(crate) const EOF_INFO: SyntaxInfo = SyntaxInfo { name: "EOF" };
-
-pub(crate) const TOMBSTONE: SyntaxKind = SyntaxKind(!0 - 1);
-pub(crate) const TOMBSTONE_INFO: SyntaxInfo = SyntaxInfo { name: "TOMBSTONE" };
-
-impl SyntaxKind {
-    fn info(self) -> &'static SyntaxInfo {
-        match self {
-            EOF => &EOF_INFO,
-            TOMBSTONE => &TOMBSTONE_INFO,
-            _ => syntax_info(self),
-        }
-    }
-}
+pub use syntax_kinds::SyntaxKind;
 
 impl fmt::Debug for SyntaxKind {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {