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Viewing changes to contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/TypeParameterSubstitution.cs

  • Committer: Package Import Robot
  • Author(s): Jo Shields
  • Date: 2013-05-12 09:46:03 UTC
  • mto: This revision was merged to the branch mainline in revision 29.
  • Revision ID: package-import@ubuntu.com-20130512094603-mad323bzcxvmcam0
Tags: upstream-4.0.5+dfsg
ImportĀ upstreamĀ versionĀ 4.0.5+dfsg

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contrib/ICSharpCode.NRefactory/TypeSystem/Implementation/TypeParameterSubstitution.cs
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ļ»æ// Copyright (c) AlphaSierraPapa for the SharpDevelop Team
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// 
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// Permission is hereby granted, free of charge, to any person obtaining a copy of this
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// software and associated documentation files (the "Software"), to deal in the Software
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// without restriction, including without limitation the rights to use, copy, modify, merge,
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// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
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// to whom the Software is furnished to do so, subject to the following conditions:
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// 
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// The above copyright notice and this permission notice shall be included in all copies or
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// substantial portions of the Software.
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// 
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
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// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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using System;
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using System.Collections.Generic;
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using System.Text;
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namespace ICSharpCode.NRefactory.TypeSystem.Implementation
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{
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        /// <summary>
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        /// Substitues class and method type parameters.
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        /// </summary>
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        public class TypeParameterSubstitution : TypeVisitor
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        {
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                /// <summary>
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                /// The identity function.
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                /// </summary>
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                public static readonly TypeParameterSubstitution Identity = new TypeParameterSubstitution(null, null);
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                readonly IList<IType> classTypeArguments;
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                readonly IList<IType> methodTypeArguments;
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                /// <summary>
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                /// Creates a new type parameter substitution.
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                /// </summary>
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                /// <param name="classTypeArguments">
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                /// The type arguments to substitute for class type parameters.
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                /// Pass <c>null</c> to keep class type parameters unmodified.
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                /// </param>
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                /// <param name="methodTypeArguments">
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                /// The type arguments to substitute for method type parameters.
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                /// Pass <c>null</c> to keep method type parameters unmodified.
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                /// </param>
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                public TypeParameterSubstitution(IList<IType> classTypeArguments, IList<IType> methodTypeArguments)
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                {
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                        this.classTypeArguments = classTypeArguments;
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                        this.methodTypeArguments = methodTypeArguments;
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                }
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                /// <summary>
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                /// Gets the list of class type arguments.
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                /// Returns <c>null</c> if this substitution keeps class type parameters unmodified.
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                /// </summary>
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                public IList<IType> ClassTypeArguments {
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                        get { return classTypeArguments; }
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                }
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                /// <summary>
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                /// Gets the list of method type arguments.
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                /// Returns <c>null</c> if this substitution keeps method type parameters unmodified.
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                /// </summary>
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                public IList<IType> MethodTypeArguments {
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                        get { return methodTypeArguments; }
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                }
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                #region Compose
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                /// <summary>
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                /// Computes a single TypeParameterSubstitution so that for all types <c>t</c>:
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                /// <c>t.AcceptVisitor(Compose(g, f)) equals t.AcceptVisitor(f).AcceptVisitor(g)</c>
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                /// </summary>
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                /// <remarks>If you consider type parameter substitution to be a function, this is function composition.</remarks>
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                public static TypeParameterSubstitution Compose(TypeParameterSubstitution g, TypeParameterSubstitution f)
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                {
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                        if (g == null)
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                                return f;
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                        if (f == null || (f.classTypeArguments == null && f.methodTypeArguments == null))
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                                return g;
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                        // The composition is a copy of 'f', with 'g' applied on the array elements.
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                        // If 'f' has a null list (keeps type parameters unmodified), we have to treat it as
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                        // the identity function, and thus use the list from 'g'.
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                        var classTypeArguments = f.classTypeArguments != null ? GetComposedTypeArguments(f.classTypeArguments, g) : g.classTypeArguments;
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                        var methodTypeArguments = f.methodTypeArguments != null ? GetComposedTypeArguments(f.methodTypeArguments, g) : g.methodTypeArguments;
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                        return new TypeParameterSubstitution(classTypeArguments, methodTypeArguments);
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                }
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                static IList<IType> GetComposedTypeArguments(IList<IType> input, TypeParameterSubstitution substitution)
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                {
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                        IType[] result = new IType[input.Count];
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                        for (int i = 0; i < result.Length; i++) {
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                                result[i] = input[i].AcceptVisitor(substitution);
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                        }
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                        return result;
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                }
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                #endregion
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                #region Equals and GetHashCode implementation
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                public override bool Equals(object obj)
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                {
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                        TypeParameterSubstitution other = obj as TypeParameterSubstitution;
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                        if (other == null)
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                                return false;
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                        return TypeListEquals(classTypeArguments, other.classTypeArguments)
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                                && TypeListEquals(methodTypeArguments, other.methodTypeArguments);
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                }
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                public override int GetHashCode()
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                {
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                        unchecked {
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                                return 1124131 * TypeListHashCode(classTypeArguments) + 1821779 * TypeListHashCode(methodTypeArguments);
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                        }
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                }
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                static bool TypeListEquals(IList<IType> a, IList<IType> b)
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                {
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                        if (a == b)
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                                return true;
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                        if (a == null || b == null)
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                                return false;
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                        if (a.Count != b.Count)
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                                return false;
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                        for (int i = 0; i < a.Count; i++) {
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                                if (!a[i].Equals(b[i]))
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                                        return false;
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                        }
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                        return true;
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                }
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                static int TypeListHashCode(IList<IType> obj)
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                {
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                        if (obj == null)
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                                return 0;
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                        unchecked {
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                                int hashCode = 1;
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                                foreach (var element in obj) {
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                                        hashCode *= 27;
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                                        hashCode += element.GetHashCode();
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                                }
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                                return hashCode;
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                        }
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                }
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                #endregion
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                public override IType VisitTypeParameter(ITypeParameter type)
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                {
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                        int index = type.Index;
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                        if (classTypeArguments != null && type.OwnerType == EntityType.TypeDefinition) {
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                                if (index >= 0 && index < classTypeArguments.Count)
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                                        return classTypeArguments[index];
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                                else
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                                        return SpecialType.UnknownType;
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                        } else if (methodTypeArguments != null && type.OwnerType == EntityType.Method) {
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                                if (index >= 0 && index < methodTypeArguments.Count)
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                                        return methodTypeArguments[index];
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                                else
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                                        return SpecialType.UnknownType;
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                        } else {
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                                return base.VisitTypeParameter(type);
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                        }
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                }
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                public override string ToString()
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                {
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                        StringBuilder b = new StringBuilder();
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                        b.Append('[');
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                        bool first = true;
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                        if (classTypeArguments != null) {
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                                for (int i = 0; i < classTypeArguments.Count; i++) {
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                                        if (first) first = false; else b.Append(", ");
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                                        b.Append('`');
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                                        b.Append(i);
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                                        b.Append(" -> ");
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                                        b.Append(classTypeArguments[i].ReflectionName);
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                                }
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                        }
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                        if (methodTypeArguments != null) {
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                                for (int i = 0; i < methodTypeArguments.Count; i++) {
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                                        if (first) first = false; else b.Append(", ");
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                                        b.Append("``");
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                                        b.Append(i);
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                                        b.Append(" -> ");
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                                        b.Append(methodTypeArguments[i].ReflectionName);
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                                }
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                        }
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                        b.Append(']');
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                        return b.ToString();
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                }
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        }
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}