AST visitor with bottom-up reading WIP

Cargo.toml

@@ -87,10 +87,12 @@ oxc_transformer = { version = "0.12.5", path = "crates/oxc_transformer" }
 oxc_sourcemap   = { version = "0.12.5", path = "crates/oxc_sourcemap" }
 
 # publish = false
+oxc_ast_macros   = { path = "crates/oxc_ast_macros" }
 oxc_macros       = { path = "crates/oxc_macros" }
 oxc_linter       = { path = "crates/oxc_linter" }
 oxc_prettier     = { path = "crates/oxc_prettier" }
 oxc_tasks_common = { path = "tasks/common" }
+oxc_traverse     = { path = "crates/oxc_traverse" }
 
 napi        = "2"
 napi-derive = "2"
@@ -110,6 +112,7 @@ ignore              = "0.4.22"
 itertools           = "0.12.1"
 jemallocator        = "0.5.4"
 lazy_static         = "1.4.0"
+memoffset           = "0.9.1"
 miette              = { version = "7.2.0", features = ["fancy-no-syscall"] }
 mimalloc            = "0.1.41"
 num-bigint          = "0.4.4"
@@ -132,6 +135,7 @@ tempfile            = "3.10.1"
 thiserror           = "1.0.59"
 tokio               = "1"
 tower-lsp           = "0.20.0"
+trybuild            = "1.0.93"
 unicode-id-start    = "1.1.2"
 ureq                = { version = "2.9.6", default-features = false }
 url                 = "2.5.0"

TODO.md

@@ -0,0 +1,22 @@
+# TODO
+
+* Set enum discriminants for `Ancestor` so that `is_*` can use bitwise ops + `retag_stack` can write 1 byte only.
+  * Compiler does not auto-optimize `matches!()` in `is_*` functions. Need to do it manually.
+  * See `ancestor_type2` branch.
+  * Need to handle big endian systems where bytes are in reverse order.
+    * That's easy, but how to run tests on big endian? Miri?
+* Implement `Debug` for `Ancestor` and `AncestorWithout*` types
+  * Implement intermediate `as_ref` method which creates an object of references, which debug can use.
+* Improve API for `Ancestor::is_via_*`
+* API to read siblings in a Vec.
+* API to get which index current node is in a Vec.
+* API to allow mutating other branches of AST
+  * I think all that's required is to:
+    * Pass `&mut TraverseCtx` to `enter_*` and `exit_*`
+    * Add `parent_mut`, `ancestor_mut` methods to `TraverseCtx`
+    * Add `span_mut`, `directives_mut` etc to all `*Without*` types
+  * Mutable borrow on `TraverseCtx` and `Ancestor` prevents creating more than 1 mut ref at a time
+  * Mutable borrow on `TraverseCtx` unfortunately also blocks calling `ctx.alloc()`.
+    * Can solve that with e.g. `ctx.ancestry.parent_mut()` + `ctx.ast.alloc()` - separate properties
+      can be mut borrowed at same time.
+* Move `Span` to constant position in all structs, for fast lookup?

crates/oxc_ast/Cargo.toml

@@ -18,9 +18,10 @@ workspace = true
 doctest = false
 
 [dependencies]
-oxc_allocator = { workspace = true }
-oxc_span      = { workspace = true }
-oxc_syntax    = { workspace = true }
+oxc_allocator  = { workspace = true }
+oxc_ast_macros = { workspace = true }
+oxc_span       = { workspace = true }
+oxc_syntax     = { workspace = true }
 
 bitflags   = { workspace = true }
 num-bigint = { workspace = true }