Explorer: split Member into dedicated classes (#2421)

Features: * Split `Member` class into 3 dedicated classes covering named, positional, and a new "base class" element Changes: * Rename `Member` to `Element` to better reflect the variants covered * Add `NamedElement`, `PositionalElement`, and `BaseElement` child classes for `Element` * Split `GetMember` into 3 function variants based on available attributes (index, name, nothing). * Add some unit tests to provide coverage of core features Motivation: This changeset splits Member into (currently 2) classes, as we see the need for more Member variants (base class access needed for #2378, possibly unnamed mixins, ...), which in addition to the current ones, also have significantly different attributes. This will allow supporting more Member types in the future cleanly. Alternatives considered: The alternative solution, "one class for positional, named & base class access", would expose unused or unavailable attributes depending on the Member actual type (`index()` only for positional, `name()` only for named, and neither for base class access).
2026-10-05 22:02:55 +01:00 · 2022-12-09 16:09:50 -08:00
parent dd2f7d732c
commit 563768c6d3
16 changed files with 507 additions and 307 deletions
@@ -0,0 +1,96 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include "explorer/ast/element.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include <optional>
+
+#include "explorer/ast/bindings.h"
+#include "explorer/ast/declaration.h"
+#include "explorer/ast/expression.h"
+#include "explorer/common/arena.h"
+#include "explorer/interpreter/value.h"
+#include "llvm/Support/Casting.h"
+
+namespace Carbon::Testing {
+namespace {
+
+static auto FakeSourceLoc(int line_num) -> SourceLocation {
+  return SourceLocation("<test>", line_num);
+}
+
+class ElementTest : public ::testing::Test {
+ protected:
+  Arena arena;
+};
+
+TEST_F(ElementTest, NamedElementType) {
+  const auto src_loc = FakeSourceLoc(1);
+  VariableDeclaration decl{
+      src_loc,
+      arena.New<BindingPattern>(src_loc, "valuename",
+                                arena.New<AutoPattern>(src_loc),
+                                ValueCategory::Var),
+      std::nullopt, ValueCategory::Var};
+  const auto* static_type = arena.New<IntValue>(1);
+  decl.set_static_type(static_type);
+  NamedElement element_decl(&decl);
+
+  EXPECT_EQ(&element_decl.type(), static_type);
+
+  NamedElement named_val(
+      arena.New<NamedValue>(NamedValue{"valuename", static_type}));
+  EXPECT_EQ(&named_val.type(), static_type);
+}
+
+TEST_F(ElementTest, NamedElementDeclaration) {
+  const auto src_loc = FakeSourceLoc(1);
+  VariableDeclaration decl{
+      src_loc,
+      arena.New<BindingPattern>(src_loc, "valuename",
+                                arena.New<AutoPattern>(src_loc),
+                                ValueCategory::Var),
+      std::nullopt, ValueCategory::Var};
+  const auto* static_type = arena.New<IntValue>(1);
+  NamedElement element_decl(&decl);
+
+  EXPECT_TRUE(element_decl.declaration());
+
+  NamedElement named_val(
+      arena.New<NamedValue>(NamedValue{"valuename", static_type}));
+  EXPECT_FALSE(named_val.declaration());
+}
+
+TEST_F(ElementTest, NamedElementIsNamed) {
+  const auto src_loc = FakeSourceLoc(1);
+  VariableDeclaration decl{
+      src_loc,
+      arena.New<BindingPattern>(src_loc, "valuename",
+                                arena.New<AutoPattern>(src_loc),
+                                ValueCategory::Var),
+      std::nullopt, ValueCategory::Var};
+  NamedElement member_decl(&decl);
+  EXPECT_TRUE(member_decl.IsNamed("valuename"));
+  EXPECT_FALSE(member_decl.IsNamed("anything"));
+
+  NamedElement named_val(
+      arena.New<NamedValue>(NamedValue{"valuename", arena.New<IntValue>(1)}));
+  EXPECT_TRUE(named_val.IsNamed("valuename"));
+  EXPECT_FALSE(named_val.IsNamed("anything"));
+}
+
+TEST_F(ElementTest, PositionalElementIsNamed) {
+  PositionalElement element(1, arena.New<IntValue>(1));
+  EXPECT_FALSE(element.IsNamed("anything"));
+}
+
+TEST_F(ElementTest, BaseElementIsNamed) {
+  BaseElement element(arena.New<IntValue>(1));
+  EXPECT_FALSE(element.IsNamed("anything"));
+}
+}  // namespace
+}  // namespace Carbon::Testing