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diff --git a/Userland/Libraries/LibJS/Interpreter.h b/Userland/Libraries/LibJS/Interpreter.h
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+++ b/Userland/Libraries/LibJS/Interpreter.h
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+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/FlyString.h>
+#include <AK/HashMap.h>
+#include <AK/String.h>
+#include <AK/Vector.h>
+#include <AK/Weakable.h>
+#include <LibJS/AST.h>
+#include <LibJS/Forward.h>
+#include <LibJS/Heap/DeferGC.h>
+#include <LibJS/Heap/Heap.h>
+#include <LibJS/Runtime/ErrorTypes.h>
+#include <LibJS/Runtime/Exception.h>
+#include <LibJS/Runtime/LexicalEnvironment.h>
+#include <LibJS/Runtime/MarkedValueList.h>
+#include <LibJS/Runtime/VM.h>
+#include <LibJS/Runtime/Value.h>
+
+namespace JS {
+
+class Interpreter : public Weakable<Interpreter> {
+public:
+    template<typename GlobalObjectType, typename... Args>
+    static NonnullOwnPtr<Interpreter> create(VM& vm, Args&&... args)
+    {
+        DeferGC defer_gc(vm.heap());
+        auto interpreter = adopt_own(*new Interpreter(vm));
+        VM::InterpreterExecutionScope scope(*interpreter);
+        interpreter->m_global_object = make_handle(static_cast<Object*>(interpreter->heap().allocate_without_global_object<GlobalObjectType>(forward<Args>(args)...)));
+        static_cast<GlobalObjectType*>(interpreter->m_global_object.cell())->initialize();
+        return interpreter;
+    }
+
+    static NonnullOwnPtr<Interpreter> create_with_existing_global_object(GlobalObject&);
+
+    ~Interpreter();
+
+    Value run(GlobalObject&, const Program&);
+
+    GlobalObject& global_object();
+    const GlobalObject& global_object() const;
+
+    VM& vm() { return *m_vm; }
+    const VM& vm() const { return *m_vm; }
+    Heap& heap() { return vm().heap(); }
+    Exception* exception() { return vm().exception(); }
+
+    ScopeObject* current_scope() { return vm().current_scope(); }
+    LexicalEnvironment* current_environment();
+
+    void enter_scope(const ScopeNode&, ScopeType, GlobalObject&);
+    void exit_scope(const ScopeNode&);
+
+    void enter_node(const ASTNode&);
+    void exit_node(const ASTNode&);
+
+    Value execute_statement(GlobalObject&, const Statement&, ScopeType = ScopeType::Block);
+
+private:
+    explicit Interpreter(VM&);
+
+    void push_scope(ScopeFrame frame);
+
+    Vector<ScopeFrame> m_scope_stack;
+
+    NonnullRefPtr<VM> m_vm;
+
+    Handle<Object> m_global_object;
+};
+
+}