scope: introduce LookupError type

3 files changed, 20 insertions, 10 deletions

diff --git a/crates/rebel-lang/src/scope.rs b/crates/rebel-lang/src/scope.rs
index 3f2e682..bb3f2e9 100644
--- a/crates/rebel-lang/src/scope.rs
+++ b/crates/rebel-lang/src/scope.rs
@@ -15,6 +15,11 @@ pub struct Var {
 	pub value: Option<Value>,
 }
 
+#[derive(Debug)]
+pub struct LookupError;
+
+pub type Result<T> = std::result::Result<T, LookupError>;
+
 #[derive(Debug, Clone)]
 pub struct Context {
 	pub vars: Module<Var>,
@@ -60,28 +65,28 @@ impl Context {
 		Some(ident)
 	}
 
-	pub fn lookup_var(&self, path: &ast::Path) -> Option<&Var> {
+	pub fn lookup_var(&self, path: &ast::Path) -> Result<&Var> {
 		if path.root != ast::PathRoot::Relative {
-			return None;
+			return Err(LookupError);
 		}
 
 		if path.components == [ast::Ident { name: "_" }] {
-			return None;
+			return Err(LookupError);
 		}
 
-		self.vars.lookup(&path.components)
+		self.vars.lookup(&path.components).ok_or(LookupError)
 	}
 
-	pub fn lookup_type(&self, path: &ast::Path) -> Option<&Type> {
+	pub fn lookup_type(&self, path: &ast::Path) -> Result<&Type> {
 		if path.root != ast::PathRoot::Relative {
-			return None;
+			return Err(LookupError);
 		}
 
 		if path.components == [ast::Ident { name: "_" }] {
-			return Some(&Type::Free);
+			return Ok(&Type::Free);
 		}
 
-		self.types.lookup(&path.components)
+		self.types.lookup(&path.components).ok_or(LookupError)
 	}
 
 	pub fn record_type(&mut self, stmt: &ast::BlockStmt) -> typing::Result<Type> {
diff --git a/crates/rebel-lang/src/typing.rs b/crates/rebel-lang/src/typing.rs
index 3fd0ee2..a441b1c 100644
--- a/crates/rebel-lang/src/typing.rs
+++ b/crates/rebel-lang/src/typing.rs
@@ -90,7 +90,7 @@ impl Type {
 	}
 
 	fn path_type(ctx: &Context, path: &ast::Path<'_>) -> Result<Type> {
-		ctx.lookup_type(path).cloned().ok_or(TypeError)
+		ctx.lookup_type(path).cloned().or(Err(TypeError))
 	}
 
 	fn literal_type(ctx: &Context, lit: &typ::Literal<'_>) -> Result<Type> {
@@ -292,7 +292,11 @@ impl Type {
 	}
 
 	fn path_expr_type(ctx: &Context, path: &ast::Path<'_>) -> Result<Type> {
-		Ok(ctx.lookup_var(path).ok_or(TypeError)?.inferred_type.clone())
+		Ok(ctx
+			.lookup_var(path)
+			.or(Err(TypeError))?
+			.inferred_type
+			.clone())
 	}
 
 	fn check_string_piece(
diff --git a/crates/rebel-lang/src/value.rs b/crates/rebel-lang/src/value.rs
index 0780377..f7bffbb 100644
--- a/crates/rebel-lang/src/value.rs
+++ b/crates/rebel-lang/src/value.rs
@@ -246,6 +246,7 @@ impl Value {
 
 	fn eval_path(ctx: &Context, path: &ast::Path<'_>) -> Result<Value> {
 		ctx.lookup_var(path)
+			.ok()
 			.and_then(|var| var.value.clone())
 			.ok_or(EvalError)
 	}