Parse relations

crates/frontend/src/ast.rs

@@ -117,10 +117,14 @@ pub enum Item<'db> {
 /// Parses [Relation] from an [AstNode].
 #[salsa::tracked]
 pub fn relation<'db>(db: &'db dyn Database, ast: AstNode) -> Relation<'db> {
-    todo!()
+    let name = ast.expect_field(db, "relation").with_contents(db);
+    let is_decision = ast.get_field(db, "decision").is_some();
+    let ty = ty(db, ast.expect_field(db, "type"));
+    Relation::new(db, name, is_decision, ty)
 }
 
 /// A definition of a relation.
+// TODO: parse IO
 #[salsa::tracked]
 pub struct Relation<'db> {
     /// The name of this relation.
@@ -129,9 +133,6 @@ pub struct Relation<'db> {
     /// Whether this relation is a decision.
     pub is_decision: bool,
 
-    /// The IO of this relation.
-    pub io: ir::RelationIO,
-
     /// This relation's abstract type (pure syntax).
     pub ty: WithAst<Type>,
 }
@@ -462,6 +463,15 @@ impl ir::EnumRepr for RedundantBinaryOpKind {
     }
 }
 
+/// Parses a type.
+pub fn ty(db: &dyn Database, ast: AstNode) -> WithAst<Type> {
+    ast.with(if let Some(ast) = ast.get_field(db, "named") {
+        Type::Named(ast.contents(db).to_string())
+    } else {
+        Type::Tuple(ast.get_fields(db, "tuple").map(|ast| ty(db, ast)).collect())
+    })
+}
+
 /// An abstract type definition.
 ///
 /// This just represents the literal, syntactic type representation, without
@@ -469,7 +479,6 @@ impl ir::EnumRepr for RedundantBinaryOpKind {
 #[derive(Clone, PartialEq, Eq, Hash)]
 pub enum Type {
     Named(String),
-    Primitive(ir::Type),
     Tuple(Vec<WithAst<Type>>),
 }
 
@@ -477,7 +486,6 @@ impl Display for Type {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             Type::Named(name) => write!(f, "{name}"),
-            Type::Primitive(ty) => write!(f, "{ty:?}"),
             Type::Tuple(els) => {
                 let els = els
                     .iter()