rust/crates/ra_hir_expand/src/hygiene.rs
2020-03-25 19:50:12 +08:00

56 lines
1.8 KiB
Rust

//! This modules handles hygiene information.
//!
//! Specifically, `ast` + `Hygiene` allows you to create a `Name`. Note that, at
//! this moment, this is horribly incomplete and handles only `$crate`.
use either::Either;
use ra_db::CrateId;
use ra_syntax::ast;
use crate::{
db::AstDatabase,
name::{AsName, Name},
HirFileId, HirFileIdRepr, MacroCallId, MacroDefKind,
};
#[derive(Debug)]
pub struct Hygiene {
// This is what `$crate` expands to
def_crate: Option<CrateId>,
}
impl Hygiene {
pub fn new(db: &dyn AstDatabase, file_id: HirFileId) -> Hygiene {
let def_crate = match file_id.0 {
HirFileIdRepr::FileId(_) => None,
HirFileIdRepr::MacroFile(macro_file) => match macro_file.macro_call_id {
MacroCallId::LazyMacro(id) => {
let loc = db.lookup_intern_macro(id);
match loc.def.kind {
MacroDefKind::Declarative => loc.def.krate,
MacroDefKind::BuiltIn(_) => None,
MacroDefKind::BuiltInDerive(_) => None,
MacroDefKind::BuiltInEager(_) => None,
MacroDefKind::CustomDerive(_) => None,
}
}
MacroCallId::EagerMacro(_id) => None,
},
};
Hygiene { def_crate }
}
pub fn new_unhygienic() -> Hygiene {
Hygiene { def_crate: None }
}
// FIXME: this should just return name
pub fn name_ref_to_name(&self, name_ref: ast::NameRef) -> Either<Name, CrateId> {
if let Some(def_crate) = self.def_crate {
if name_ref.text() == "$crate" {
return Either::Right(def_crate);
}
}
Either::Left(name_ref.as_name())
}
}