/IronPython_Main/Runtime/Tests/TestAst/TestScope.cs

/* ****************************************************************************

 *

 * Copyright (c) Microsoft Corporation. 

 *

 * This source code is subject to terms and conditions of the Apache License, Version 2.0. A 

 * copy of the license can be found in the License.html file at the root of this distribution. If 

 * you cannot locate the  Apache License, Version 2.0, please send an email to 

 * ironpy@microsoft.com. By using this source code in any fashion, you are agreeing to be bound 

 * by the terms of the Apache License, Version 2.0.

 *

 * You must not remove this notice, or any other, from this software.

 *

 *

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#if !CLR2

using System.Linq.Expressions;

#endif



using System;

using System.Collections.Generic;

using System.Dynamic;

using Microsoft.Scripting.Ast;

using Microsoft.Scripting.Runtime;



namespace TestAst {

    public class TestScope {

        private TestScope _parent;

        private LambdaBuilder _block;

        private Dictionary<string, ParameterExpression> _variables = new Dictionary<string, ParameterExpression>();



        //////////////////////////////////////////////////////////

        public static TestScope Current = null;

        public static void PushNewScope(string name) {

            Current = new TestScope(name, Current);

        }

        public static void PopScope() {

            Current = Current.Parent;

        }

        //////////////////////////////////////////////////////////



        public TestScope(string name, TestScope parent) {

            _block = Utils.Lambda(typeof(object), name);

            _parent = parent;

            Current = this;

        }



        public TestScope Parent {

            get {

                return _parent;

            }

        }



        public TestScope TopScope {

            get {

                if (_parent == null) {

                    return this;

                } else {

                    return _parent.TopScope;

                }

            }

        }



        public LambdaBuilder Block {

            get {

                return _block;

            }

        }



        public ParameterExpression GetOrMakeLocal(string name) {

            return GetOrMakeLocal(name, typeof(object));

        }



        public ParameterExpression GetOrMakeLocal(string name, Type type) {

            ParameterExpression ret;

            if (_variables.TryGetValue(name, out ret)) {

                return ret;

            }

            ret = (ParameterExpression)_block.Variable(type, name);

            _variables[name] = ret;

            return ret;

        }



        public ParameterExpression LookupName(string name) {

            ParameterExpression var;

            if (_variables.TryGetValue(name, out var)) {

                return var;

            }



            if (_parent != null) {

                return _parent.LookupName(name);

            } else {

                return null;

            }

        }



        public ParameterExpression HiddenVariable(Type type, string name) {

            return _block.HiddenVariable(type, name);

        }



        public LambdaExpression FinishScope(Expression body) {

            _block.Body = body;

            _block.AddParameters(Expression.Parameter(typeof(Scope), "#scope"), Expression.Parameter(typeof(LanguageContext), "#context"));

            

            return _block.MakeLambda();

        }

    }

}