From d542bbe69697518b873afaec358339fb2c003eb3 Mon Sep 17 00:00:00 2001
From: Robert Bendun <robben@st.amu.edu.pl>
Date: Sat, 21 May 2022 23:12:50 +0200
Subject: [PATCH] Small refactoring

---
 src/environment.cc |  4 +---
 src/musique.hh     | 10 +++++++---
 src/value.cc       |  5 +++--
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/environment.cc b/src/environment.cc
index a91454e..0e74f2b 100644
--- a/src/environment.cc
+++ b/src/environment.cc
@@ -27,7 +27,6 @@ Value* Env::find(std::string const& name)
 
 usize Env::operator++() const
 {
-	std::cerr << "ENTER SCOPE" << std::endl;
 	auto const parent_id = this - pool->data();
 	auto const free = std::find_if(pool->begin(), pool->end(), [](Env const& env) { return env.parent_enviroment_id == Env::Unused; });
 	Env* next = free == pool->end()
@@ -40,8 +39,7 @@ usize Env::operator++() const
 
 usize Env::operator--()
 {
-	std::cerr << "LEAVE SCOPE" << std::endl;
-	if (this == pool->data())
+	if (this == &Env::global())
 		return 0;
 	variables.clear();
 	return std::exchange(parent_enviroment_id, Unused);
diff --git a/src/musique.hh b/src/musique.hh
index d96270f..e54a79b 100644
--- a/src/musique.hh
+++ b/src/musique.hh
@@ -159,7 +159,11 @@ struct [[nodiscard("This value may contain critical error, so it should NOT be i
 	inline auto value() &&
 	{
 		if constexpr (not std::is_void_v<T>) {
-			return Storage::value();
+			// NOTE This line in ideal world should be `return Storage::value()`
+			// but C++ does not infer that this is rvalue context.
+			// `std::add_rvalue_reference_t<Storage>::value()`
+			// also does not work, so this is probably the best way to express this:
+			return std::move(*static_cast<Storage*>(this)).value();
 		}
 	}
 
@@ -464,7 +468,7 @@ struct Value
 	Value& operator=(Value &&) = default;
 
 	template<typename Callable>
-	requires (!std::is_same_v<std::remove_cvref_t<Callable>, Value>)
+	requires (!std::is_same_v<std::decay_t<Callable>, Value>)
 		&& std::invocable<Callable, Interpreter&, std::vector<Value>>
 		&& is_one_of<std::invoke_result_t<Callable, Interpreter&, std::vector<Value>>, Value, Result<Value>>
 	inline Value(Callable &&callable)
@@ -535,7 +539,7 @@ struct Interpreter
 
 	Interpreter();
 	~Interpreter();
-	Interpreter(std::ostream& out);
+	explicit Interpreter(std::ostream& out);
 	Interpreter(Interpreter const&) = delete;
 	Interpreter(Interpreter &&) = default;
 
diff --git a/src/value.cc b/src/value.cc
index 75eea17..6503f35 100644
--- a/src/value.cc
+++ b/src/value.cc
@@ -4,7 +4,7 @@ Result<Value> Value::from(Token t)
 {
 	switch (t.type) {
 	case Token::Type::Numeric:
-		return Number::from(std::move(t)).map(Value::number);
+		return Value::number(Try(Number::from(std::move(t))));
 
 	case Token::Type::Symbol:
 		if (t.source == "true")
@@ -137,7 +137,8 @@ Result<Value> Lambda::operator()(Interpreter &i, std::vector<Value> arguments)
 		env.force_define(parameters[j], std::move(arguments[j]));
 	}
 
-	auto result = i.eval((Ast)body);
+	Ast body_copy = body;
+	auto result = i.eval(std::move(body_copy));
 
 	i.current_env = --i.env();
 	return result;