Add an environment implementation

include/serene/environment.h

@@ -0,0 +1,61 @@
+/* -*- C++ -*-
+ * Serene programming language.
+ *
+ *  Copyright (c) 2019-2021 Sameer Rahmani <lxsameer@gnu.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef SERENE_ENVIRONMENT_H
+#define SERENE_ENVIRONMENT_H
+
+#include "mlir/Support/LogicalResult.h"
+#include "llvm/ADT/DenseMap.h"
+
+namespace serene {
+
+template <typename K, typename V> class Environment {
+  Environment<K, V> *parent;
+  llvm::DenseMap<K, V> pairs;
+
+public:
+  Environment() : parent(nullptr) {}
+  Environment(Environment *parent) : parent(parent){};
+
+  llvm::Optional<V> lookup(K key) {
+    if (auto value = pairs.lookup(key)) {
+      return value;
+    }
+
+    if (parent) {
+      return parent->lookup(key);
+    }
+
+    return llvm::None;
+  };
+
+  mlir::LogicalResult insert_symbol(K key, V value) {
+    pairs.insert(std::pair<K, V>(key, value));
+    return mlir::success();
+  };
+};
+
+} // namespace serene
+
+#endif

src/serene/CMakeLists.txt

@@ -2,6 +2,7 @@ set(HEADER_LIST
   "${INCLUDE_DIR}/serene/serene.h"
   "${INCLUDE_DIR}/serene/utils.h"
   "${INCLUDE_DIR}/serene/context.h"
+  "${INCLUDE_DIR}/serene/environment.h"
 
   "${INCLUDE_DIR}/serene/exprs/expression.h"
   "${INCLUDE_DIR}/serene/exprs/symbol.h"

src/tests/environment_tests.cpp.inc

@@ -0,0 +1,65 @@
+/* -*- C++ -*-
+ * Serene programming language.
+ *
+ *  Copyright (c) 2019-2021 Sameer Rahmani <lxsameer@gnu.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "./test_helpers.cpp.inc"
+#include "serene/environment.h"
+#include "serene/exprs/expression.h"
+#include "serene/exprs/symbol.h"
+#include "llvm/ADT/StringRef.h"
+#include <catch2/catch.hpp>
+
+namespace serene {
+
+
+TEST_CASE("Environment tests", "[environment]") {
+  std::unique_ptr<reader::LocationRange> range(dummyLocation());
+
+  exprs::node sym = exprs::make<exprs::Symbol>(*range.get(), llvm::StringRef("example"));
+
+  Environment<llvm::StringRef, exprs::node> e;
+  llvm::Optional<exprs::node> result = e.lookup("a");
+
+  REQUIRE_FALSE(result.hasValue());
+
+  auto status = e.insert_symbol("a", sym);
+
+  REQUIRE(status.succeeded());
+
+  result = e.lookup("a");
+
+  REQUIRE(result.hasValue());
+  CHECK(result.getValue() == sym);
+
+  Environment<llvm::StringRef, exprs::node> e1(&e);
+
+  result = e1.lookup("b");
+  REQUIRE_FALSE(result.hasValue());
+
+  // It should lookup the value in the parent environment
+  result = e1.lookup("a");
+  REQUIRE(result.hasValue());
+  CHECK(result.getValue() == sym);
+};
+
+} // namespace serene

src/tests/serenetests.cpp

@@ -23,6 +23,7 @@
  */
 
 #define CATCH_CONFIG_MAIN
+#include "./environment_tests.cpp.inc"
 #include "./errors/error_tests.cpp.inc"
 #include "./exprs/expression_tests.cpp.inc"
 #include "./exprs/list_tests.cpp.inc"