Everywhere: Start implementation of step2

src/eval.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2023 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include "ast.h"
+#include "environment.h"
+
+namespace blaze {
+
+class Eval {
+public:
+	Eval(ASTNode* ast, Environment* env);
+	virtual ~Eval() = default;
+
+	void eval();
+
+	ASTNode* ast() const { return m_ast; }
+
+private:
+	ASTNode* evalImpl(ASTNode* ast, Environment* env);
+	ASTNode* evalAst(ASTNode* ast, Environment* env);
+	ASTNode* apply(List* evaluated_list);
+
+	ASTNode* m_ast { nullptr };
+	Environment* m_env { nullptr };
+};
+
+} // namespace blaze