diff options
Diffstat (limited to 'crates/span/src')
| -rw-r--r-- | crates/span/src/hygiene.rs | 129 | ||||
| -rw-r--r-- | crates/span/src/lib.rs | 44 |
2 files changed, 136 insertions, 37 deletions
diff --git a/crates/span/src/hygiene.rs b/crates/span/src/hygiene.rs new file mode 100644 index 00000000000..18da689922b --- /dev/null +++ b/crates/span/src/hygiene.rs @@ -0,0 +1,129 @@ +//! Machinery for hygienic macros. +//! +//! Inspired by Matthew Flatt et al., “Macros That Work Together: Compile-Time Bindings, Partial +//! Expansion, and Definition Contexts,” *Journal of Functional Programming* 22, no. 2 +//! (March 1, 2012): 181–216, <https://doi.org/10.1017/S0956796812000093>. +//! +//! Also see https://rustc-dev-guide.rust-lang.org/macro-expansion.html#hygiene-and-hierarchies +//! +//! # The Expansion Order Hierarchy +//! +//! `ExpnData` in rustc, rust-analyzer's version is [`MacroCallLoc`]. Traversing the hierarchy +//! upwards can be achieved by walking up [`MacroCallLoc::kind`]'s contained file id, as +//! [`MacroFile`]s are interned [`MacroCallLoc`]s. +//! +//! # The Macro Definition Hierarchy +//! +//! `SyntaxContextData` in rustc and rust-analyzer. Basically the same in both. +//! +//! # The Call-site Hierarchy +//! +//! `ExpnData::call_site` in rustc, [`MacroCallLoc::call_site`] in rust-analyzer. +use std::fmt; + +use salsa::{InternId, InternValue}; + +use crate::MacroCallId; + +/// Interned [`SyntaxContextData`]. +#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)] +pub struct SyntaxContextId(InternId); + +impl salsa::InternKey for SyntaxContextId { + fn from_intern_id(v: salsa::InternId) -> Self { + SyntaxContextId(v) + } + fn as_intern_id(&self) -> salsa::InternId { + self.0 + } +} + +impl fmt::Display for SyntaxContextId { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "{}", self.0.as_u32()) + } +} + +impl SyntaxContextId { + /// The root context, which is the parent of all other contexts. All [`FileId`]s have this context. + pub const ROOT: Self = SyntaxContextId(unsafe { InternId::new_unchecked(0) }); + + pub fn is_root(self) -> bool { + self == Self::ROOT + } + + /// Deconstruct a `SyntaxContextId` into a raw `u32`. + /// This should only be used for deserialization purposes for the proc-macro server. + pub fn into_u32(self) -> u32 { + self.0.as_u32() + } + + /// Constructs a `SyntaxContextId` from a raw `u32`. + /// This should only be used for serialization purposes for the proc-macro server. + pub fn from_u32(u32: u32) -> Self { + Self(InternId::from(u32)) + } +} + +/// A syntax context describes a hierarchy tracking order of macro definitions. +#[derive(Copy, Clone, Hash, PartialEq, Eq)] +pub struct SyntaxContextData { + pub outer_expn: Option<MacroCallId>, + pub outer_transparency: Transparency, + pub parent: SyntaxContextId, + /// This context, but with all transparent and semi-transparent expansions filtered away. + pub opaque: SyntaxContextId, + /// This context, but with all transparent expansions filtered away. + pub opaque_and_semitransparent: SyntaxContextId, +} + +impl InternValue for SyntaxContextData { + type Key = (SyntaxContextId, Option<MacroCallId>, Transparency); + + fn into_key(&self) -> Self::Key { + (self.parent, self.outer_expn, self.outer_transparency) + } +} + +impl std::fmt::Debug for SyntaxContextData { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.debug_struct("SyntaxContextData") + .field("outer_expn", &self.outer_expn) + .field("outer_transparency", &self.outer_transparency) + .field("parent", &self.parent) + .field("opaque", &self.opaque) + .field("opaque_and_semitransparent", &self.opaque_and_semitransparent) + .finish() + } +} + +impl SyntaxContextData { + pub fn root() -> Self { + SyntaxContextData { + outer_expn: None, + outer_transparency: Transparency::Opaque, + parent: SyntaxContextId::ROOT, + opaque: SyntaxContextId::ROOT, + opaque_and_semitransparent: SyntaxContextId::ROOT, + } + } +} + +/// A property of a macro expansion that determines how identifiers +/// produced by that expansion are resolved. +#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Hash, Debug)] +pub enum Transparency { + /// Identifier produced by a transparent expansion is always resolved at call-site. + /// Call-site spans in procedural macros, hygiene opt-out in `macro` should use this. + Transparent, + /// Identifier produced by a semi-transparent expansion may be resolved + /// either at call-site or at definition-site. + /// If it's a local variable, label or `$crate` then it's resolved at def-site. + /// Otherwise it's resolved at call-site. + /// `macro_rules` macros behave like this, built-in macros currently behave like this too, + /// but that's an implementation detail. + SemiTransparent, + /// Identifier produced by an opaque expansion is always resolved at definition-site. + /// Def-site spans in procedural macros, identifiers from `macro` by default use this. + Opaque, +} diff --git a/crates/span/src/lib.rs b/crates/span/src/lib.rs index 7763d75cc92..00f82646077 100644 --- a/crates/span/src/lib.rs +++ b/crates/span/src/lib.rs @@ -3,9 +3,14 @@ use std::fmt::{self, Write}; use salsa::InternId; +mod hygiene; mod map; -pub use crate::map::{RealSpanMap, SpanMap}; +pub use self::{ + hygiene::{SyntaxContextData, SyntaxContextId, Transparency}, + map::{RealSpanMap, SpanMap}, +}; + pub use syntax::{TextRange, TextSize}; pub use vfs::FileId; @@ -23,7 +28,7 @@ pub struct FileRange { pub type ErasedFileAstId = la_arena::Idx<syntax::SyntaxNodePtr>; -// The first inde is always the root node's AstId +// The first index is always the root node's AstId pub const ROOT_ERASED_FILE_AST_ID: ErasedFileAstId = la_arena::Idx::from_raw(la_arena::RawIdx::from_u32(0)); @@ -68,41 +73,6 @@ impl fmt::Display for Span { } } -#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)] -pub struct SyntaxContextId(InternId); - -impl salsa::InternKey for SyntaxContextId { - fn from_intern_id(v: salsa::InternId) -> Self { - SyntaxContextId(v) - } - fn as_intern_id(&self) -> salsa::InternId { - self.0 - } -} - -impl fmt::Display for SyntaxContextId { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - write!(f, "{}", self.0.as_u32()) - } -} - -// inherent trait impls please tyvm -impl SyntaxContextId { - pub const ROOT: Self = SyntaxContextId(unsafe { InternId::new_unchecked(0) }); - - pub fn is_root(self) -> bool { - self == Self::ROOT - } - - pub fn into_u32(self) -> u32 { - self.0.as_u32() - } - - pub fn from_u32(u32: u32) -> Self { - Self(InternId::from(u32)) - } -} - #[derive(Copy, Clone, PartialEq, Eq, Hash)] pub struct SpanAnchor { pub file_id: FileId, |