/WCFWebApi/src/Microsoft.ApplicationServer.Http/Microsoft/ApplicationServer/Query/DynamicQueryable.cs

// <copyright>

//   Copyright (c) Microsoft Corporation.  All rights reserved.

// </copyright>



namespace Microsoft.ApplicationServer.Query

{

    using System;

    using System.Collections.Generic;

    using System.Globalization;

    using System.Linq;

    using System.Linq.Expressions;

    using System.Reflection;

    using Microsoft.ApplicationServer.Http;



    internal static class DynamicQueryable

    {

        public static IQueryable Where(this IQueryable source, string predicate, QueryResolver queryResolver)

        {

            if (source == null)

                throw new ArgumentNullException("source");

            if (predicate == null)

                throw new ArgumentNullException("predicate");

            LambdaExpression lambda = DynamicExpression.ParseLambda(source.ElementType, typeof(bool), predicate, queryResolver);

            return source.Provider.CreateQuery(

                Expression.Call(

                    typeof(Queryable), "Where",

                    new Type[] { source.ElementType },

                    source.Expression, Expression.Quote(lambda)));

        }



        public static IQueryable OrderBy(this IQueryable source, string ordering, QueryResolver queryResolver)

        {

            if (source == null)

                throw new ArgumentNullException("source");

            if (ordering == null)

                throw new ArgumentNullException("ordering");

            ParameterExpression[] parameters = new ParameterExpression[] {

                Expression.Parameter(source.ElementType, "") };

            ExpressionParser parser = new ExpressionParser(parameters, ordering, queryResolver);

            IEnumerable<DynamicOrdering> orderings = parser.ParseOrdering();

            Expression queryExpr = source.Expression;

            string methodAsc = "OrderBy";

            string methodDesc = "OrderByDescending";

            foreach (DynamicOrdering o in orderings)

            {

                queryExpr = Expression.Call(

                    typeof(Queryable), o.Ascending ? methodAsc : methodDesc,

                    new Type[] { source.ElementType, o.Selector.Type },

                    queryExpr, Expression.Quote(DynamicExpression.Lambda(o.Selector, parameters)));

                methodAsc = "ThenBy";

                methodDesc = "ThenByDescending";

            }

            return source.Provider.CreateQuery(queryExpr);

        }



        public static IQueryable Take(this IQueryable source, int count)

        {

            if (source == null)

                throw new ArgumentNullException("source");

            return source.Provider.CreateQuery(

                Expression.Call(

                    typeof(Queryable), "Take",

                    new Type[] { source.ElementType },

                    source.Expression, Expression.Constant(count)));

        }



        public static IQueryable Skip(this IQueryable source, int count)

        {

            if (source == null)

                throw new ArgumentNullException("source");

            return source.Provider.CreateQuery(

                Expression.Call(

                    typeof(Queryable), "Skip",

                    new Type[] { source.ElementType },

                    source.Expression, Expression.Constant(count)));

        }

    }



    internal static class DynamicExpression

    {

        static readonly Type[] funcTypes = new Type[] {

            typeof(Func<>),

            typeof(Func<,>),

            typeof(Func<,,>),

            typeof(Func<,,,>),

            typeof(Func<,,,,>)

        };



        public static LambdaExpression ParseLambda(Type itType, Type resultType, string expression, QueryResolver queryResolver)

        {

            return ParseLambda(new ParameterExpression[] { Expression.Parameter(itType, "") }, resultType, expression, queryResolver);

        }



        public static LambdaExpression ParseLambda(ParameterExpression[] parameters, Type resultType, string expression, QueryResolver queryResolver)

        {

            ExpressionParser parser = new ExpressionParser(parameters, expression, queryResolver);

            return Lambda(parser.Parse(resultType), parameters);

        }



        public static LambdaExpression Lambda(Expression body, params ParameterExpression[] parameters)

        {

            int paramCount = parameters == null ? 0 : parameters.Length;

            Type[] typeArgs = new Type[paramCount + 1];

            for (int i = 0; i < paramCount; i++)

                typeArgs[i] = parameters[i].Type;

            typeArgs[paramCount] = body.Type;

            return Expression.Lambda(GetFuncType(typeArgs), body, parameters);

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2208:InstantiateArgumentExceptionsCorrectly", Justification = "Arguments are provided internally by the parser's ParserLambda methods.")]

        public static Type GetFuncType(params Type[] typeArgs)

        {

            if (typeArgs == null || typeArgs.Length < 1 || typeArgs.Length > 5)

                throw new ArgumentException();

            return funcTypes[typeArgs.Length - 1].MakeGenericType(typeArgs);

        }

    }



    internal class DynamicOrdering

    {

        public Expression Selector;

        public bool Ascending;

    }



    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1032:ImplementStandardExceptionConstructors", Justification = "Exception is intended to only be used by the dynamic parser.")]

    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1064:ExceptionsShouldBePublic", Justification = "Exception is intended to only be used by the dynamic parser.")]

    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2237:MarkISerializableTypesWithSerializable", Justification = "Exception is intended to only be used by the dynamic parser.")]

    internal class ParseException : Exception

    {

        public ParseException(string message, int position)

            : base(string.Format(CultureInfo.InvariantCulture, SR.ParseExceptionFormat(message, position)))

        {

        }

    }



    internal class ExpressionParser

    {

        struct Token

        {

            public TokenId id;

            public string text;

            public int pos;

        }



        enum TokenId

        {

            Unknown,

            End,

            Identifier,

            StringLiteral,

            IntegerLiteral,

            RealLiteral,

            Exclamation,

            Percent,

            Amphersand,

            OpenParen,

            CloseParen,

            Asterisk,

            Plus,

            Comma,

            Minus,

            Dot,

            Slash,

            Colon,

            LessThan,

            Equal,

            GreaterThan,

            Question,

            OpenBracket,

            CloseBracket,

            Bar,

            ExclamationEqual,

            DoubleAmphersand,

            LessThanEqual,

            LessGreater,

            DoubleEqual,

            GreaterThanEqual,

            DoubleBar

        }



        internal class MappedMemberInfo

        {

            public MappedMemberInfo(Type mappedType, string memberName, bool isStatic, bool isMethod)

            {

                MappedType = mappedType;

                MemberName = memberName;

                IsStatic = isStatic;

                IsMethod = isMethod;

            }



            public Type MappedType { get; private set; }

            public string MemberName { get; private set; }

            public bool IsStatic { get; private set; }

            public bool IsMethod { get; private set; }

        }



        interface ILogicalSignatures

        {

            void F(bool x, bool y);

            void F(bool? x, bool? y);

        }



        interface IArithmeticSignatures

        {

            void F(int x, int y);

            void F(uint x, uint y);

            void F(long x, long y);

            void F(ulong x, ulong y);

            void F(float x, float y);

            void F(double x, double y);

            void F(decimal x, decimal y);

            void F(int? x, int? y);

            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.MSInternal", "CA908:AvoidTypesThatRequireJitCompilationInPrecompiledAssemblies", Justification = "Legacy code.")]

            void F(uint? x, uint? y);

            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.MSInternal", "CA908:AvoidTypesThatRequireJitCompilationInPrecompiledAssemblies", Justification = "Legacy code.")]

            void F(long? x, long? y);

            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.MSInternal", "CA908:AvoidTypesThatRequireJitCompilationInPrecompiledAssemblies", Justification = "Legacy code.")]

            void F(ulong? x, ulong? y);

            void F(float? x, float? y);

            void F(double? x, double? y);

            void F(decimal? x, decimal? y);

        }



        interface IRelationalSignatures : IArithmeticSignatures

        {

            void F(string x, string y);

            void F(char x, char y);

            void F(DateTime x, DateTime y);

            void F(TimeSpan x, TimeSpan y);

            void F(char? x, char? y);

            void F(DateTime? x, DateTime? y);

            void F(TimeSpan? x, TimeSpan? y);

            void F(DateTimeOffset x, DateTimeOffset y);

            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.MSInternal", "CA908:AvoidTypesThatRequireJitCompilationInPrecompiledAssemblies", Justification = "Legacy code.")]

            void F(DateTimeOffset? x, DateTimeOffset? y);

        }



        interface IEqualitySignatures : IRelationalSignatures

        {

            void F(bool x, bool y);

            void F(bool? x, bool? y);

            void F(Guid x, Guid y);

            void F(Guid? x, Guid? y);

        }



        interface IAddSignatures : IArithmeticSignatures

        {

            void F(DateTime x, TimeSpan y);

            void F(TimeSpan x, TimeSpan y);

            void F(DateTime? x, TimeSpan? y);

            void F(TimeSpan? x, TimeSpan? y);

            void F(DateTimeOffset x, TimeSpan y);

            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.MSInternal", "CA908:AvoidTypesThatRequireJitCompilationInPrecompiledAssemblies", Justification = "Legacy code.")]

            void F(DateTimeOffset? x, TimeSpan? y);

        }



        interface ISubtractSignatures : IAddSignatures

        {

            void F(DateTime x, DateTime y);

            void F(DateTime? x, DateTime? y);

            void F(DateTimeOffset x, DateTimeOffset y);

            [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.MSInternal", "CA908:AvoidTypesThatRequireJitCompilationInPrecompiledAssemblies", Justification = "Legacy code.")]

            void F(DateTimeOffset? x, DateTimeOffset? y);

        }



        interface INegationSignatures

        {

            void F(int x);

            void F(long x);

            void F(float x);

            void F(double x);

            void F(decimal x);

            void F(int? x);

            void F(long? x);

            void F(float? x);

            void F(double? x);

            void F(decimal? x);

        }



        interface INotSignatures

        {

            void F(bool x);

            void F(bool? x);

        }



        interface IEnumerableSignatures

        {

            void Where(bool predicate);

            void Any();

            void Any(bool predicate);

            void All(bool predicate);

            void Count();

            void Count(bool predicate);

            void Min(object selector);

            void Max(object selector);

            void Sum(int selector);

            void Sum(int? selector);

            void Sum(long selector);

            void Sum(long? selector);

            void Sum(float selector);

            void Sum(float? selector);

            void Sum(double selector);

            void Sum(double? selector);

            void Sum(decimal selector);

            void Sum(decimal? selector);

            void Average(int selector);

            void Average(int? selector);

            void Average(long selector);

            void Average(long? selector);

            void Average(float selector);

            void Average(float? selector);

            void Average(double selector);

            void Average(double? selector);

            void Average(decimal selector);

            void Average(decimal? selector);

        }



        static readonly Type[] predefinedTypes = {

            typeof(Object),

            typeof(Boolean),

            typeof(Char),

            typeof(String),

            typeof(SByte),

            typeof(Byte),

            typeof(Int16),

            typeof(UInt16),

            typeof(Int32),

            typeof(UInt32),

            typeof(Int64),

            typeof(UInt64),

            typeof(Single),

            typeof(Double),

            typeof(Decimal),

            typeof(DateTime),

            typeof(DateTimeOffset),

            typeof(TimeSpan),

            typeof(Guid),

            typeof(Math),

            typeof(Convert),

            typeof(StringComparison),

            typeof(Uri)

        };



        static readonly Expression trueLiteral = Expression.Constant(true);

        static readonly Expression falseLiteral = Expression.Constant(false);

        static readonly Expression nullLiteral = Expression.Constant(null);



        const string keywordIt = "it";

        const string keywordIif = "iif";



        static Dictionary<string, object> keywords;



        Dictionary<string, object> symbols;

        Dictionary<Expression, string> literals;

        ParameterExpression it;

        string text;

        int textPos;

        int textLen;

        char ch;

        Token token;

        QueryResolver queryResolver;



        public ExpressionParser(ParameterExpression[] parameters, string expression, QueryResolver queryResolver)

        {

            if (expression == null)

                throw new ArgumentNullException("expression");

            if (keywords == null)

                keywords = CreateKeywords();

            this.queryResolver = queryResolver;

            symbols = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);

            literals = new Dictionary<Expression, string>();

            if (parameters != null)

                ProcessParameters(parameters);

            text = expression;

            textLen = text.Length;

            SetTextPos(0);

            NextToken();

        }



        void ProcessParameters(ParameterExpression[] parameters)

        {

            foreach (ParameterExpression pe in parameters)

                if (!String.IsNullOrEmpty(pe.Name))

                    AddSymbol(pe.Name, pe);

            if (parameters.Length == 1 && String.IsNullOrEmpty(parameters[0].Name))

                it = parameters[0];

        }



        void AddSymbol(string name, object value)

        {

            if (symbols.ContainsKey(name))

                throw ParseError(SR.DuplicateIdentifier(name));

            symbols.Add(name, value);

        }



        public Expression Parse(Type resultType)

        {

            int exprPos = token.pos;

            Expression expr = ParseExpression();

            if (resultType != null)

                if ((expr = PromoteExpression(expr, resultType, true)) == null)

                    throw ParseError(exprPos, SR.ExpressionTypeMismatch(GetTypeName(resultType)));

            ValidateToken(TokenId.End, SR.SyntaxError);

            return expr;

        }



#pragma warning disable 0219

        public IEnumerable<DynamicOrdering> ParseOrdering()

        {

            List<DynamicOrdering> orderings = new List<DynamicOrdering>();

            while (true)

            {

                Expression expr = ParseExpression();

                bool ascending = true;

                if (TokenIdentifierIs("asc") || TokenIdentifierIs("ascending"))

                {

                    NextToken();

                }

                else if (TokenIdentifierIs("desc") || TokenIdentifierIs("descending"))

                {

                    NextToken();

                    ascending = false;

                }

                orderings.Add(new DynamicOrdering

                {

                    Selector = expr,

                    Ascending = ascending

                });

                if (token.id != TokenId.Comma)

                    break;

                NextToken();

            }

            ValidateToken(TokenId.End, SR.SyntaxError);

            return orderings;

        }

#pragma warning restore 0219



        // ?: operator

        Expression ParseExpression()

        {

            int errorPos = token.pos;

            Expression expr = ParseLogicalOr();

            if (token.id == TokenId.Question)

            {

                NextToken();

                Expression expr1 = ParseExpression();

                ValidateToken(TokenId.Colon, SR.ColonExpected);

                NextToken();

                Expression expr2 = ParseExpression();

                expr = GenerateConditional(expr, expr1, expr2, errorPos);

            }

            return expr;

        }



        // ||, or operator

        Expression ParseLogicalOr()

        {

            Expression left = ParseLogicalAnd();

            while (token.id == TokenId.DoubleBar || TokenIdentifierIs("or"))

            {

                Token op = token;

                NextToken();

                Expression right = ParseLogicalAnd();

                CheckAndPromoteOperands(typeof(ILogicalSignatures), op.text, ref left, ref right, op.pos);

                left = Expression.OrElse(left, right);

            }

            return left;

        }



        // &&, and operator

        Expression ParseLogicalAnd()

        {

            Expression left = ParseComparison();

            while (token.id == TokenId.DoubleAmphersand || TokenIdentifierIs("and"))

            {

                Token op = token;

                NextToken();

                Expression right = ParseComparison();

                CheckAndPromoteOperands(typeof(ILogicalSignatures), op.text, ref left, ref right, op.pos);

                left = Expression.AndAlso(left, right);

            }

            return left;

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity", Justification = "Legacy code.")]

        // =, ==, !=, <>, >, >=, <, <= operators

        Expression ParseComparison()

        {

            Expression left = ParseAdditive();

            while (token.id == TokenId.Equal || token.id == TokenId.DoubleEqual ||

                token.id == TokenId.ExclamationEqual || token.id == TokenId.LessGreater ||

                token.id == TokenId.GreaterThan || token.id == TokenId.GreaterThanEqual ||

                token.id == TokenId.LessThan || token.id == TokenId.LessThanEqual)

            {

                Token op = token;

                NextToken();

                Expression right = ParseAdditive();

                bool isEquality = op.id == TokenId.Equal || op.id == TokenId.DoubleEqual ||

                    op.id == TokenId.ExclamationEqual || op.id == TokenId.LessGreater;

                if (isEquality && !left.Type.IsValueType && !right.Type.IsValueType)

                {

                    if (left.Type != right.Type)

                    {

                        if (left.Type.IsAssignableFrom(right.Type))

                        {

                            right = Expression.Convert(right, left.Type);

                        }

                        else if (right.Type.IsAssignableFrom(left.Type))

                        {

                            left = Expression.Convert(left, right.Type);

                        }

                        else

                        {

                            throw IncompatibleOperandsError(op.text, left, right, op.pos);

                        }

                    }

                }

                else if (IsEnumType(left.Type) || IsEnumType(right.Type))

                {

                    // convert enum expressions to their underlying values for comparison

                    left = ConvertEnumExpression(left, right);

                    right = ConvertEnumExpression(right, left);



                    CheckAndPromoteOperands(isEquality ? typeof(IEqualitySignatures) : typeof(IRelationalSignatures),

                        op.text, ref left, ref right, op.pos);

                }

                else

                {

                    CheckAndPromoteOperands(isEquality ? typeof(IEqualitySignatures) : typeof(IRelationalSignatures),

                        op.text, ref left, ref right, op.pos);

                }

                switch (op.id)

                {

                    case TokenId.Equal:

                    case TokenId.DoubleEqual:

                        left = GenerateEqual(left, right);

                        break;

                    case TokenId.ExclamationEqual:

                    case TokenId.LessGreater:

                        left = GenerateNotEqual(left, right);

                        break;

                    case TokenId.GreaterThan:

                        left = GenerateGreaterThan(left, right);

                        break;

                    case TokenId.GreaterThanEqual:

                        left = GenerateGreaterThanEqual(left, right);

                        break;

                    case TokenId.LessThan:

                        left = GenerateLessThan(left, right);

                        break;

                    case TokenId.LessThanEqual:

                        left = GenerateLessThanEqual(left, right);

                        break;

                }

            }

            return left;

        }



        /// <summary>

        /// We perform comparisons against enums using the underlying type

        /// because a more complete set of comparisons can be performed.

        /// </summary>

        static Expression ConvertEnumExpression(Expression expr, Expression otherExpr)

        {

            if (!IsEnumType(expr.Type))

            {

                return expr;

            }



            Type underlyingType;

            if (IsNullableType(expr.Type) ||

                (otherExpr.NodeType == ExpressionType.Constant && ((ConstantExpression)otherExpr).Value == null))

            {

                // if the enum expression itself is nullable or is being compared against null

                // we use a nullable type

                underlyingType = typeof(Nullable<>).MakeGenericType(Enum.GetUnderlyingType(GetNonNullableType(expr.Type)));

            }

            else

            {

                underlyingType = Enum.GetUnderlyingType(expr.Type);

            }



            return Expression.Convert(expr, underlyingType);

        }



        // +, -, & operators

        Expression ParseAdditive()

        {

            Expression left = ParseMultiplicative();

            while (token.id == TokenId.Plus || token.id == TokenId.Minus ||

                token.id == TokenId.Amphersand)

            {

                Token op = token;

                NextToken();

                Expression right = ParseMultiplicative();

                switch (op.id)

                {

                    case TokenId.Plus:

                        if (left.Type == typeof(string) || right.Type == typeof(string))

                            goto case TokenId.Amphersand;

                        CheckAndPromoteOperands(typeof(IAddSignatures), op.text, ref left, ref right, op.pos);

                        left = GenerateAdd(left, right);

                        break;

                    case TokenId.Minus:

                        CheckAndPromoteOperands(typeof(ISubtractSignatures), op.text, ref left, ref right, op.pos);

                        left = GenerateSubtract(left, right);

                        break;

                    case TokenId.Amphersand:

                        left = GenerateStringConcat(left, right);

                        break;

                }

            }

            return left;

        }



        // *, /, %, mod operators

        Expression ParseMultiplicative()

        {

            Expression left = ParseUnary();

            while (token.id == TokenId.Asterisk || token.id == TokenId.Slash ||

                token.id == TokenId.Percent || TokenIdentifierIs("mod"))

            {

                Token op = token;

                NextToken();

                Expression right = ParseUnary();

                CheckAndPromoteOperands(typeof(IArithmeticSignatures), op.text, ref left, ref right, op.pos);

                switch (op.id)

                {

                    case TokenId.Asterisk:

                        left = Expression.Multiply(left, right);

                        break;

                    case TokenId.Slash:

                        left = Expression.Divide(left, right);

                        break;

                    case TokenId.Percent:

                    case TokenId.Identifier:

                        left = Expression.Modulo(left, right);

                        break;

                }

            }

            return left;

        }



        // -, !, not unary operators

        Expression ParseUnary()

        {

            if (token.id == TokenId.Minus || token.id == TokenId.Exclamation ||

                TokenIdentifierIs("not"))

            {

                Token op = token;

                NextToken();

                if (op.id == TokenId.Minus && (token.id == TokenId.IntegerLiteral ||

                    token.id == TokenId.RealLiteral))

                {

                    token.text = "-" + token.text;

                    token.pos = op.pos;

                    return ParsePrimary();

                }

                Expression expr = ParseUnary();

                if (op.id == TokenId.Minus)

                {

                    CheckAndPromoteOperand(typeof(INegationSignatures), op.text, ref expr, op.pos);

                    expr = Expression.Negate(expr);

                }

                else

                {

                    CheckAndPromoteOperand(typeof(INotSignatures), op.text, ref expr, op.pos);

                    expr = Expression.Not(expr);

                }

                return expr;

            }

            return ParsePrimary();

        }



        Expression ParsePrimary()

        {

            Expression expr = ParsePrimaryStart();

            while (true)

            {

                if (token.id == TokenId.Dot)

                {

                    NextToken();

                    expr = ParseMemberAccess(null, expr);

                }

                else if (token.id == TokenId.OpenBracket)

                {

                    expr = ParseElementAccess(expr);

                }

                else

                {

                    break;

                }

            }

            return expr;

        }



        Expression ParsePrimaryStart()

        {

            switch (token.id)

            {

                case TokenId.Identifier:

                    return ParseIdentifier();

                case TokenId.StringLiteral:

                    return ParseStringLiteral();

                case TokenId.IntegerLiteral:

                    return ParseIntegerLiteral();

                case TokenId.RealLiteral:

                    return ParseRealLiteral();

                case TokenId.OpenParen:

                    return ParseParenExpression();

                default:

                    throw ParseError(SR.ExpressionExpected);

            }

        }



        Expression ParseStringLiteral()

        {

            ValidateToken(TokenId.StringLiteral);

            char quote = token.text[0];

            // Unwrap string (remove surrounding quotes) and unwrap backslashes.

            string s = token.text.Substring(1, token.text.Length - 2).Replace("\\\\", "\\");



            if (quote == '\'')

            {

                // Unwrap single quotes.

                s = s.Replace("\\\'", "\'");

            }

            else

            {

                // Unwrap double quotes.

                s = s.Replace("\\\"", "\"");



                // TODO : do we need this code anymore?

            }



            NextToken();

            return CreateLiteral(s, s);

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Maintainability", "CA1500:VariableNamesShouldNotMatchFieldNames", Justification = "Legacy code.")]

        Expression ParseIntegerLiteral()

        {

            ValidateToken(TokenId.IntegerLiteral);

            string text = token.text;

            if (text[0] != '-')

            {

                ulong value;

                if (!UInt64.TryParse(text, NumberStyles.None, CultureInfo.InvariantCulture, out value))

                    throw ParseError(SR.InvalidIntegerLiteral(text));

                NextToken();

                if (value <= (ulong)Int32.MaxValue)

                    return CreateLiteral((int)value, text);

                if (value <= (ulong)UInt32.MaxValue)

                    return CreateLiteral((uint)value, text);

                if (value <= (ulong)Int64.MaxValue)

                    return CreateLiteral((long)value, text);

                return CreateLiteral(value, text);

            }

            else

            {

                long value;

                if (!Int64.TryParse(text, NumberStyles.AllowLeadingSign, CultureInfo.InvariantCulture, out value))

                    throw ParseError(SR.InvalidIntegerLiteral(text));

                NextToken();

                if (value >= Int32.MinValue && value <= Int32.MaxValue)

                    return CreateLiteral((int)value, text);

                return CreateLiteral(value, text);

            }

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Maintainability", "CA1500:VariableNamesShouldNotMatchFieldNames", Justification = "Legacy code.")]

        Expression ParseRealLiteral()

        {

            ValidateToken(TokenId.RealLiteral);

            string text = token.text;

            object value = null;

            char last = text[text.Length - 1];

            if (last == 'F' || last == 'f')

            {

                float f;

                if (Single.TryParse(text.Substring(0, text.Length - 1), NumberStyles.Number | NumberStyles.AllowExponent, CultureInfo.InvariantCulture, out f))

                    value = f;

            }

            else if (last == 'M' || last == 'm')

            {

                decimal m;

                if (Decimal.TryParse(text.Substring(0, text.Length - 1), NumberStyles.Number | NumberStyles.AllowExponent, CultureInfo.InvariantCulture, out m))

                    value = m;

            }

            else if (last == 'D' || last == 'd')

            {

                double d;

                if (Double.TryParse(text.Substring(0, text.Length - 1), NumberStyles.Number | NumberStyles.AllowExponent, CultureInfo.InvariantCulture, out d))

                    value = d;

            }

            else

            {

                double d;

                if (Double.TryParse(text, NumberStyles.Number | NumberStyles.AllowExponent, CultureInfo.InvariantCulture, out d))

                    value = d;

            }

            if (value == null)

                throw ParseError(SR.InvalidRealLiteral(text));

            NextToken();

            return CreateLiteral(value, text);

        }



        Expression CreateLiteral(object value, string valueAsString)

        {

            ConstantExpression expr = Expression.Constant(value);

            literals.Add(expr, valueAsString);

            return expr;

        }



        Expression ParseParenExpression()

        {

            ValidateToken(TokenId.OpenParen, SR.OpenParenExpected);

            NextToken();

            Expression e = ParseExpression();

            ValidateToken(TokenId.CloseParen, SR.CloseParenOrOperatorExpected);

            NextToken();

            return e;

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily", Justification = "Legacy code.")]

        Expression ParseIdentifier()

        {

            ValidateToken(TokenId.Identifier);

            object value;

            if (keywords.TryGetValue(token.text, out value))

            {

                if (value is Type)

                    return ParseTypeAccess((Type)value);

                if (value == (object)keywordIt)

                    return ParseIt();

                if (value == (object)keywordIif)

                    return ParseIif();

                NextToken();

                return (Expression)value;

            }



            if (symbols.TryGetValue(token.text, out value))

            {

                Expression expr = value as Expression;

                if (expr == null)

                {

                    expr = Expression.Constant(value);

                }

                NextToken();

                return expr;

            }



            // See if the token is a mapped function call

            MappedMemberInfo mappedFunction = MapFunction(token.text);

            if (mappedFunction != null)

            {

                return ParseMappedFunction(mappedFunction);

            }



            if (it != null)

                return ParseMemberAccess(null, it);



            throw ParseError(SR.UnknownIdentifier(token.text));

        }



        MappedMemberInfo MapFunction(string functionName)

        {

            MappedMemberInfo mappedMember = MapStringFunction(functionName);

            if (mappedMember != null)

            {

                return mappedMember;

            }



            mappedMember = MapDateFunction(functionName);

            if (mappedMember != null)

            {

                return mappedMember;

            }



            mappedMember = MapMathFunction(functionName);

            if (mappedMember != null)

            {

                return mappedMember;

            }



            return null;

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "Legacy code.")]

        MappedMemberInfo MapStringFunction(string functionName)

        {

            if (functionName == "startswith")

            {

                return new MappedMemberInfo(typeof(string), "StartsWith", false, true);

            }

            else if (functionName == "endswith")

            {

                return new MappedMemberInfo(typeof(string), "EndsWith", false, true);

            }

            else if (functionName == "length")

            {

                return new MappedMemberInfo(typeof(string), "Length", false, false);

            }

            else if (functionName == "toupper")

            {

                return new MappedMemberInfo(typeof(string), "ToUpper", false, true);

            }

            else if (functionName == "tolower")

            {

                return new MappedMemberInfo(typeof(string), "ToLower", false, true);

            }

            else if (functionName == "substringof")

            {

                return new MappedMemberInfo(typeof(string), "Contains", false, true);

            }

            else if (functionName == "indexof")

            {

                return new MappedMemberInfo(typeof(string), "IndexOf", false, true);

            }

            else if (functionName == "replace")

            {

                return new MappedMemberInfo(typeof(string), "Replace", false, true);

            }

            else if (functionName == "substring")

            {

                return new MappedMemberInfo(typeof(string), "Substring", false, true);

            }

            else if (functionName == "trim")

            {

                return new MappedMemberInfo(typeof(string), "Trim", false, true);

            }

            else if (functionName == "concat")

            {

                return new MappedMemberInfo(typeof(string), "Concat", true, true);

            }



            return null;

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "Legacy code.")]

        MappedMemberInfo MapDateFunction(string functionName)

        {

            // date functions

            if (functionName == "day")

            {

                return new MappedMemberInfo(typeof(DateTime), "Day", false, false);

            }

            else if (functionName == "month")

            {

                return new MappedMemberInfo(typeof(DateTime), "Month", false, false);

            }

            else if (functionName == "year")

            {

                return new MappedMemberInfo(typeof(DateTime), "Year", false, false);

            }

            else if (functionName == "hour")

            {

                return new MappedMemberInfo(typeof(DateTime), "Hour", false, false);

            }

            else if (functionName == "minute")

            {

                return new MappedMemberInfo(typeof(DateTime), "Minute", false, false);

            }

            else if (functionName == "second")

            {

                return new MappedMemberInfo(typeof(DateTime), "Second", false, false);

            }



            return null;

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "Legacy code.")]

        MappedMemberInfo MapMathFunction(string functionName)

        {

            if (functionName == "round")

            {

                return new MappedMemberInfo(typeof(Math), "Round", true, true);

            }

            if (functionName == "floor")

            {

                return new MappedMemberInfo(typeof(Math), "Floor", true, true);

            }

            if (functionName == "ceiling")

            {

                return new MappedMemberInfo(typeof(Math), "Ceiling", true, true);

            }



            return null;

        }



        Expression ParseIt()

        {

            if (it == null)

                throw ParseError(SR.NoItInScope);

            NextToken();

            return it;

        }



        Expression ParseIif()

        {

            int errorPos = token.pos;

            NextToken();

            Expression[] args = ParseArgumentList();

            if (args.Length != 3)

                throw ParseError(errorPos, SR.IifRequiresThreeArgs);

            return GenerateConditional(args[0], args[1], args[2], errorPos);

        }



        Expression GenerateConditional(Expression test, Expression expr1, Expression expr2, int errorPos)

        {

            if (test.Type != typeof(bool))

                throw ParseError(errorPos, SR.FirstExprMustBeBool);

            if (expr1.Type != expr2.Type)

            {

                Expression expr1as2 = expr2 != nullLiteral ? PromoteExpression(expr1, expr2.Type, true) : null;

                Expression expr2as1 = expr1 != nullLiteral ? PromoteExpression(expr2, expr1.Type, true) : null;

                if (expr1as2 != null && expr2as1 == null)

                {

                    expr1 = expr1as2;

                }

                else if (expr2as1 != null && expr1as2 == null)

                {

                    expr2 = expr2as1;

                }

                else

                {

                    string type1 = expr1 != nullLiteral ? expr1.Type.Name : "null";

                    string type2 = expr2 != nullLiteral ? expr2.Type.Name : "null";

                    if (expr1as2 != null && expr2as1 != null)

                        throw ParseError(errorPos, SR.BothTypesConvertToOther(type1, type2));

                    throw ParseError(errorPos, SR.NeitherTypeConvertsToOther(type1, type2));

                }

            }

            return Expression.Condition(test, expr1, expr2);

        }



        Expression ParseTypeAccess(Type type)

        {

            int errorPos = token.pos;

            NextToken();

            if (token.id == TokenId.Question)

            {

                if (!type.IsValueType || IsNullableType(type))

                    throw ParseError(errorPos, SR.TypeHasNoNullableForm(GetTypeName(type)));

                type = typeof(Nullable<>).MakeGenericType(type);

                NextToken();

            }

            if (token.id == TokenId.OpenParen)

            {

                Expression[] args = ParseArgumentList();

                MethodBase method;

                switch (FindBestMethod(type.GetConstructors(), args, out method))

                {

                    case 0:

                        if (args.Length == 1)

                            return GenerateConversion(args[0], type, errorPos);

                        throw ParseError(errorPos, SR.NoMatchingConstructor(GetTypeName(type)));

                    case 1:

                        return Expression.New((ConstructorInfo)method, args);

                    default:

                        throw ParseError(errorPos, SR.AmbiguousConstructorInvocation(GetTypeName(type)));

                }

            }

            ValidateToken(TokenId.Dot, SR.DotOrOpenParenExpected);

            NextToken();

            return ParseMemberAccess(type, null);

        }



        static Expression GenerateConversion(Expression expr, Type type, int errorPos)

        {

            Type exprType = expr.Type;

            if (exprType == type)

                return expr;

            if (exprType.IsValueType && type.IsValueType)

            {

                if ((IsNullableType(exprType) || IsNullableType(type)) &&

                    GetNonNullableType(exprType) == GetNonNullableType(type))

                    return Expression.Convert(expr, type);

                if ((IsNumericType(exprType) || IsEnumType(exprType)) &&

                    (IsNumericType(type) || IsEnumType(type)))

                    return Expression.ConvertChecked(expr, type);

            }

            if (exprType.IsAssignableFrom(type) || type.IsAssignableFrom(exprType) ||

                exprType.IsInterface || type.IsInterface)

                return Expression.Convert(expr, type);

            throw ParseError(errorPos, SR.CannotConvertValue(

                GetTypeName(exprType), GetTypeName(type)));

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily", Justification = "Legacy code.")]

        Expression ParseMappedFunction(MappedMemberInfo mappedMember)

        {

            Type type = mappedMember.MappedType;

            string mappedMemberName = mappedMember.MemberName;



            int errorPos = token.pos;

            Expression[] args = null;

            Expression paramArg = null;

            Expression instance = null;



            NextToken();

            if (token.id == TokenId.OpenParen)

            {

                args = ParseArgumentList();



                // TODO : verify the first argument is the param

                // Really what we'll want to do here is allow either to be the param

                paramArg = args[0];

                instance = paramArg;



                // static methods need to include the target

                if (!mappedMember.IsStatic)

                {

                    args = args.Skip(1).ToArray();

                }

                else

                {

                    instance = null;

                }

            }



            if (mappedMember.IsMethod)

            {

                // a mapped function

                MethodBase mb;

                switch (FindMethod(type, mappedMemberName, mappedMember.IsStatic, args, out mb))

                {

                    case 0:

                        throw ParseError(errorPos, SR.NoApplicableMethod(

                            mappedMemberName, GetTypeName(type)));

                    case 1:

                        MethodInfo method = (MethodInfo)mb;

                        if (!IsPredefinedType(method.DeclaringType))

                            throw ParseError(errorPos, SR.MethodsAreInaccessible(GetTypeName(method.DeclaringType)));

                        if (method.ReturnType == typeof(void))

                            throw ParseError(errorPos, SR.MethodIsVoid(

                                mappedMemberName, GetTypeName(method.DeclaringType)));

                        return Expression.Call(instance, (MethodInfo)method, args);

                    default:

                        throw ParseError(errorPos, SR.AmbiguousMethodInvocation(

                            mappedMemberName, GetTypeName(type)));

                }

            }

            else

            {

                // a mapped Property/Field

                MemberInfo member = FindPropertyOrField(type, mappedMemberName, mappedMember.IsStatic);

                if (member == null)

                {

                    if (this.queryResolver != null)

                    {

                        MemberExpression mex = queryResolver.ResolveMember(type, mappedMemberName, instance);

                        if (mex != null)

                        {

                            return mex;

                        }

                    }

                    throw ParseError(errorPos, SR.UnknownPropertyOrField(

                        mappedMemberName, GetTypeName(type)));

                }



                return member is PropertyInfo ?

                    Expression.Property(instance, (PropertyInfo)member) :

                    Expression.Field(instance, (FieldInfo)member);

            }

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily", Justification = "Legacy code.")]

        Expression ParseMemberAccess(Type type, Expression instance)

        {

            if (instance != null)

                type = instance.Type;

            int errorPos = token.pos;

            string id = GetIdentifier();

            NextToken();

            if (token.id == TokenId.OpenParen)

            {

                if (instance != null && type != typeof(string))

                {

                    Type enumerableType = FindGenericType(typeof(IEnumerable<>), type);

                    if (enumerableType != null)

                    {

                        Type elementType = enumerableType.GetGenericArguments()[0];

                        return ParseAggregate(instance, elementType, id, errorPos);

                    }

                }

                Expression[] args = ParseArgumentList();

                MethodBase mb;

                switch (FindMethod(type, id, instance == null, args, out mb))

                {

                    case 0:

                        throw ParseError(errorPos, SR.NoApplicableMethod(

                            id, GetTypeName(type)));

                    case 1:

                        MethodInfo method = (MethodInfo)mb;

                        if (!IsPredefinedType(method.DeclaringType))

                            throw ParseError(errorPos, SR.MethodsAreInaccessible(GetTypeName(method.DeclaringType)));

                        if (method.ReturnType == typeof(void))

                            throw ParseError(errorPos, SR.MethodIsVoid(

                                id, GetTypeName(method.DeclaringType)));

                        return Expression.Call(instance, (MethodInfo)method, args);

                    default:

                        throw ParseError(errorPos, SR.AmbiguousMethodInvocation(

                            id, GetTypeName(type)));

                }

            }

            else

            {

                MemberInfo member = FindPropertyOrField(type, id, instance == null);

                if (member == null)

                {

                    if (this.queryResolver != null)

                    {

                        MemberExpression mex = queryResolver.ResolveMember(type, id, instance);

                        if (mex != null)

                        {

                            return mex;

                        }

                    }

                    throw ParseError(errorPos, SR.UnknownPropertyOrField(

                        id, GetTypeName(type)));

                }

                return member is PropertyInfo ?

                    Expression.Property(instance, (PropertyInfo)member) :

                    Expression.Field(instance, (FieldInfo)member);

            }

        }



        static Type FindGenericType(Type generic, Type type)

        {

            while (type != null && type != typeof(object))

            {

                if (type.IsGenericType && type.GetGenericTypeDefinition() == generic)

                    return type;

                if (generic.IsInterface)

                {

                    foreach (Type intfType in type.GetInterfaces())

                    {

                        Type found = FindGenericType(generic, intfType);

                        if (found != null)

                            return found;

                    }

                }

                type = type.BaseType;

            }

            return null;

        }



        Expression ParseAggregate(Expression instance, Type elementType, string methodName, int errorPos)

        {

            ParameterExpression outerIt = it;

            ParameterExpression innerIt = Expression.Parameter(elementType, "");

            it = innerIt;

            Expression[] args = ParseArgumentList();

            it = outerIt;

            MethodBase signature;

            if (FindMethod(typeof(IEnumerableSignatures), methodName, false, args, out signature) != 1)

                throw ParseError(errorPos, SR.NoApplicableAggregate(methodName));

            Type[] typeArgs;

            if (signature.Name == "Min" || signature.Name == "Max")

            {

                typeArgs = new Type[] { elementType, args[0].Type };

            }

            else

            {

                typeArgs = new Type[] { elementType };

            }

            if (args.Length == 0)

            {

                args = new Expression[] { instance };

            }

            else

            {

                args = new Expression[] { instance, DynamicExpression.Lambda(args[0], innerIt) };

            }

            return Expression.Call(typeof(Enumerable), signature.Name, typeArgs, args);

        }



        Expression[] ParseArgumentList()

        {

            ValidateToken(TokenId.OpenParen, SR.OpenParenExpected);

            NextToken();

            Expression[] args = token.id != TokenId.CloseParen ? ParseArguments() : new Expression[0];

            ValidateToken(TokenId.CloseParen, SR.CloseParenOrCommaExpected);

            NextToken();

            return args;

        }



        Expression[] ParseArguments()

        {

            List<Expression> argList = new List<Expression>();

            while (true)

            {

                argList.Add(ParseExpression());

                if (token.id != TokenId.Comma)

                    break;

                NextToken();

            }

            return argList.ToArray();

        }



        Expression ParseElementAccess(Expression expr)

        {

            int errorPos = token.pos;

            ValidateToken(TokenId.OpenBracket, SR.OpenParenExpected);

            NextToken();

            Expression[] args = ParseArguments();

            ValidateToken(TokenId.CloseBracket, SR.CloseBracketOrCommaExpected);

            NextToken();

            if (expr.Type.IsArray)

            {

                if (expr.Type.GetArrayRank() != 1 || args.Length != 1)

                    throw ParseError(errorPos, SR.CannotIndexMultiDimArray);

                Expression index = PromoteExpression(args[0], typeof(int), true);

                if (index == null)

                    throw ParseError(errorPos, SR.InvalidIndex);

                return Expression.ArrayIndex(expr, index);

            }

            else

            {

                MethodBase mb;

                switch (FindIndexer(expr.Type, args, out mb))

                {

                    case 0:

                        throw ParseError(errorPos, SR.NoApplicableIndexer(

                            GetTypeName(expr.Type)));

                    case 1:

                        return Expression.Call(expr, (MethodInfo)mb, args);

                    default:

                        throw ParseError(errorPos, SR.AmbiguousIndexerInvocation(

                            GetTypeName(expr.Type)));

                }

            }

        }



        static bool IsPredefinedType(Type type)

        {

            type = GetNonNullableType(type);

            foreach (Type t in predefinedTypes)

                if (t == type)

                    return true;

            return false;

        }



        static bool IsNullableType(Type type)

        {

            return type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>);

        }



        static Type GetNonNullableType(Type type)

        {

            return IsNullableType(type) ? type.GetGenericArguments()[0] : type;

        }



        internal static string GetTypeName(Type type)

        {

            Type baseType = GetNonNullableType(type);

            string s = baseType.Name;

            if (type != baseType)

                s += '?';

            return s;

        }



        static bool IsNumericType(Type type)

        {

            return GetNumericTypeKind(type) != 0;

        }



        static bool IsSignedIntegralType(Type type)

        {

            return GetNumericTypeKind(type) == 2;

        }



        static bool IsUnsignedIntegralType(Type type)

        {

            return GetNumericTypeKind(type) == 3;

        }



        static int GetNumericTypeKind(Type type)

        {

            type = GetNonNullableType(type);

            if (type.IsEnum)

                return 0;

            switch (Type.GetTypeCode(type))

            {

                case TypeCode.Char:

                case TypeCode.Single:

                case TypeCode.Double:

                case TypeCode.Decimal:

                    return 1;

                case TypeCode.SByte:

                case TypeCode.Int16:

                case TypeCode.Int32:

                case TypeCode.Int64:

                    return 2;

                case TypeCode.Byte:

                case TypeCode.UInt16:

                case TypeCode.UInt32:

                case TypeCode.UInt64:

                    return 3;

                default:

                    return 0;

            }

        }



        static bool IsEnumType(Type type)

        {

            return GetNonNullableType(type).IsEnum;

        }



        void CheckAndPromoteOperand(Type signatures, string opName, ref Expression expr, int errorPos)

        {

            Expression[] args = new Expression[] { expr };

            MethodBase method;

            if (FindMethod(signatures, "F", false, args, out method) != 1)

                throw ParseError(errorPos, SR.IncompatibleOperand(

                    opName, GetTypeName(args[0].Type)));

            expr = args[0];

        }



        void CheckAndPromoteOperands(Type signatures, string opName, ref Expression left, ref Expression right, int errorPos)

        {

            Expression[] args = new Expression[] { left, right };

            MethodBase method;

            if (FindMethod(signatures, "F", false, args, out method) != 1)

                throw IncompatibleOperandsError(opName, left, right, errorPos);

            left = args[0];

            right = args[1];

        }



        static Exception IncompatibleOperandsError(string opName, Expression left, Expression right, int pos)

        {

            return ParseError(pos, SR.IncompatibleOperands(

                opName, GetTypeName(left.Type), GetTypeName(right.Type)));

        }



        static MemberInfo FindPropertyOrField(Type type, string memberName, bool staticAccess)

        {

            BindingFlags flags = BindingFlags.Public | BindingFlags.DeclaredOnly |

                (staticAccess ? BindingFlags.Static : BindingFlags.Instance);

            foreach (Type t in SelfAndBaseTypes(type))

            {

                MemberInfo[] members = t.FindMembers(MemberTypes.Property | MemberTypes.Field,

                    flags, Type.FilterNameIgnoreCase, memberName);

                if (members.Length != 0)

                    return members[0];

            }

            return null;

        }



        int FindMethod(Type type, string methodName, bool staticAccess, Expression[] args, out MethodBase method)

        {

            BindingFlags flags = BindingFlags.Public | BindingFlags.DeclaredOnly |

                (staticAccess ? BindingFlags.Static : BindingFlags.Instance);

            foreach (Type t in SelfAndBaseTypes(type))

            {

                MemberInfo[] members = t.FindMembers(MemberTypes.Method,

                    flags, Type.FilterNameIgnoreCase, methodName);

                int count = FindBestMethod(members.Cast<MethodBase>(), args, out method);

                if (count != 0)

                    return count;

            }

            method = null;

            return 0;

        }



        int FindIndexer(Type type, Expression[] args, out MethodBase method)

        {

            foreach (Type t in SelfAndBaseTypes(type))

            {

                MemberInfo[] members = t.GetDefaultMembers();

                if (members.Length != 0)

                {

                    IEnumerable<MethodBase> methods = members.

                        OfType<PropertyInfo>().

                        Select(p => (MethodBase)p.GetGetMethod()).

                        Where(m => m != null);

                    int count = FindBestMethod(methods, args, out method);

                    if (count != 0)

                        return count;

                }

            }

            method = null;

            return 0;

        }



        static IEnumerable<Type> SelfAndBaseTypes(Type type)

        {

            if (type.IsInterface)

            {

                List<Type> types = new List<Type>();

                AddInterface(types, type);

                return types;

            }

            return SelfAndBaseClasses(type);

        }



        static IEnumerable<Type> SelfAndBaseClasses(Type type)

        {

            while (type != null)

            {

                yield return type;

                type = type.BaseType;

            }

        }



        static void AddInterface(List<Type> types, Type type)

        {

            if (!types.Contains(type))

            {

                types.Add(type);

                foreach (Type t in type.GetInterfaces())

                    AddInterface(types, t);

            }

        }



        class MethodData

        {

            public MethodBase MethodBase;

            public ParameterInfo[] Parameters;

            public Expression[] Args;

        }



        int FindBestMethod(IEnumerable<MethodBase> methods, Expression[] args, out MethodBase method)

        {

            MethodData[] applicable = methods.

                Select(m => new MethodData

                {

                    MethodBase = m,

                    Parameters = m.GetParameters()

                }).

                Where(m => IsApplicable(m, args)).

                ToArray();

            if (applicable.Length > 1)

            {

                applicable = applicable.

                    Where(m => applicable.All(n => m == n || IsBetterThan(args, m, n))).

                    ToArray();

            }

            if (applicable.Length == 1)

            {

                MethodData md = applicable[0];

                for (int i = 0; i < args.Length; i++)

                    args[i] = md.Args[i];

                method = md.MethodBase;

            }

            else

            {

                method = null;

            }

            return applicable.Length;

        }



        bool IsApplicable(MethodData method, Expression[] args)

        {

            if (method.Parameters.Length != args.Length)

                return false;

            Expression[] promotedArgs = new Expression[args.Length];

            for (int i = 0; i < args.Length; i++)

            {

                ParameterInfo pi = method.Parameters[i];

                if (pi.IsOut)

                    return false;

                Expression promoted = PromoteExpression(args[i], pi.ParameterType, false);

                if (promoted == null)

                    return false;

                promotedArgs[i] = promoted;

            }

            method.Args = promotedArgs;

            return true;

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Maintainability", "CA1500:VariableNamesShouldNotMatchFieldNames", Justification = "Legacy code.")]

        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily", Justification = "Legacy code.")]

        Expression PromoteExpression(Expression expr, Type type, bool exact)

        {

            if (expr.Type == type)

                return expr;

            if (expr is ConstantExpression)

            {

                ConstantExpression ce = (ConstantExpression)expr;

                if (ce == nullLiteral)

                {

                    if (!type.IsValueType || IsNullableType(type))

                        return Expression.Constant(null, type);

                }

                else

                {

                    string text;

                    if (literals.TryGetValue(ce, out text))

                    {

                        Type target = GetNonNullableType(type);

                        Object value = null;

                        switch (Type.GetTypeCode(ce.Type))

                        {

                            case TypeCode.Int32:

                            case TypeCode.UInt32:

                            case TypeCode.Int64:

                            case TypeCode.UInt64:

                                if (target.IsEnum)

                                {

                                    // promoting from a number to an enum

                                    value = Enum.Parse(target, text);

                                }

                                else if (target == typeof(char))

                                {

                                    // promote from a number to a char

                                    value = Convert.ToChar(ce.Value, CultureInfo.InvariantCulture);

                                }

                                else

                                {

                                    value = ParseNumber(text, target);

                                }

                                break;

                            case TypeCode.Double:

                                if (target == typeof(decimal))

                                    value = ParseNumber(text, target);

                                break;

                            case TypeCode.String:

                                value = ParseEnum(text, target);

                                break;

                        }

                        if (value != null)

                            return Expression.Constant(value, type);

                    }

                }

            }

            if (IsCompatibleWith(expr.Type, type))

            {

                if (type.IsValueType || exact)

                    return Expression.Convert(expr, type);

                return expr;

            }

            return null;

        }



        static object ParseNumber(string text, Type type)

        {

            switch (Type.GetTypeCode(GetNonNullableType(type)))

            {

                case TypeCode.SByte:

                    sbyte sb;

                    if (sbyte.TryParse(text, NumberStyles.AllowLeadingSign, CultureInfo.InvariantCulture, out sb))

                        return sb;

                    break;

                case TypeCode.Byte:

                    byte b;

                    if (byte.TryParse(text, NumberStyles.None, CultureInfo.InvariantCulture, out b))

                        return b;

                    break;

                case TypeCode.Int16:

                    short s;

                    if (short.TryParse(text, NumberStyles.AllowLeadingSign, CultureInfo.InvariantCulture, out s))

                        return s;

                    break;

                case TypeCode.UInt16:

                    ushort us;

                    if (ushort.TryParse(text, NumberStyles.None, CultureInfo.InvariantCulture, out us))

                        return us;

                    break;

                case TypeCode.Int32:

                    int i;

                    if (int.TryParse(text, NumberStyles.AllowLeadingSign, CultureInfo.InvariantCulture, out i))

                        return i;

                    break;

                case TypeCode.UInt32:

                    uint ui;

                    if (uint.TryParse(text, NumberStyles.None, CultureInfo.InvariantCulture, out ui))

                        return ui;

                    break;

                case TypeCode.Int64:

                    long l;

                    if (long.TryParse(text, NumberStyles.AllowLeadingSign, CultureInfo.InvariantCulture, out l))

                        return l;

                    break;

                case TypeCode.UInt64:

                    ulong ul;

                    if (ulong.TryParse(text, NumberStyles.None, CultureInfo.InvariantCulture, out ul))

                        return ul;

                    break;

                case TypeCode.Single:

                    float f;

                    if (float.TryParse(text, NumberStyles.Number, CultureInfo.InvariantCulture, out f))

                        return f;

                    break;

                case TypeCode.Double:

                    double d;

                    if (double.TryParse(text, NumberStyles.Number, CultureInfo.InvariantCulture, out d))

                        return d;

                    break;

                case TypeCode.Decimal:

                    decimal e;

                    if (decimal.TryParse(text, NumberStyles.Number, CultureInfo.InvariantCulture, out e))

                        return e;

                    break;

            }

            return null;

        }



        static object ParseEnum(string name, Type type)

        {

            if (type.IsEnum)

            {

                MemberInfo[] memberInfos = type.FindMembers(MemberTypes.Field,

                    BindingFlags.Public | BindingFlags.DeclaredOnly | BindingFlags.Static,

                    Type.FilterNameIgnoreCase, name);

                if (memberInfos.Length != 0)

                    return ((FieldInfo)memberInfos[0]).GetValue(null);

            }

            return null;

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity", Justification = "Legacy code.")]

        static bool IsCompatibleWith(Type source, Type target)

        {

            if (source == target)

                return true;

            if (!target.IsValueType)

                return target.IsAssignableFrom(source);

            Type st = GetNonNullableType(source);

            Type tt = GetNonNullableType(target);

            if (st != source && tt == target)

                return false;

            TypeCode sc = st.IsEnum ? TypeCode.Object : Type.GetTypeCode(st);

            TypeCode tc = tt.IsEnum ? TypeCode.Object : Type.GetTypeCode(tt);

            switch (sc)

            {

                case TypeCode.SByte:

                    switch (tc)

                    {

                        case TypeCode.SByte:

                        case TypeCode.Int16:

                        case TypeCode.Int32:

                        case TypeCode.Int64:

                        case TypeCode.Single:

                        case TypeCode.Double:

                        case TypeCode.Decimal:

                            return true;

                    }

                    break;

                case TypeCode.Byte:

                    switch (tc)

                    {

                        case TypeCode.Byte:

                        case TypeCode.Int16:

                        case TypeCode.UInt16:

                        case TypeCode.Int32:

                        case TypeCode.UInt32:

                        case TypeCode.Int64:

                        case TypeCode.UInt64:

                        case TypeCode.Single:

                        case TypeCode.Double:

                        case TypeCode.Decimal:

                            return true;

                    }

                    break;

                case TypeCode.Int16:

                    switch (tc)

                    {

                        case TypeCode.Int16:

                        case TypeCode.Int32:

                        case TypeCode.Int64:

                        case TypeCode.Single:

                        case TypeCode.Double:

                        case TypeCode.Decimal:

                            return true;

                    }

                    break;

                case TypeCode.UInt16:

                    switch (tc)

                    {

                        case TypeCode.UInt16:

                        case TypeCode.Int32:

                        case TypeCode.UInt32:

                        case TypeCode.Int64:

                        case TypeCode.UInt64:

                        case TypeCode.Single:

                        case TypeCode.Double:

                        case TypeCode.Decimal:

                            return true;

                    }

                    break;

                case TypeCode.Int32:

                    switch (tc)

                    {

                        case TypeCode.Int32:

                        case TypeCode.Int64:

                        case TypeCode.Single:

                        case TypeCode.Double:

                        case TypeCode.Decimal:

                            return true;

                    }

                    break;

                case TypeCode.UInt32:

                    switch (tc)

                    {

                        case TypeCode.UInt32:

                        case TypeCode.Int64:

                        case TypeCode.UInt64:

                        case TypeCode.Single:

                        case TypeCode.Double:

                        case TypeCode.Decimal:

                            return true;

                    }

                    break;

                case TypeCode.Int64:

                    switch (tc)

                    {

                        case TypeCode.Int64:

                        case TypeCode.Single:

                        case TypeCode.Double:

                        case TypeCode.Decimal:

                            return true;

                    }

                    break;

                case TypeCode.UInt64:

                    switch (tc)

                    {

                        case TypeCode.UInt64:

                        case TypeCode.Single:

                        case TypeCode.Double:

                        case TypeCode.Decimal:

                            return true;

                    }

                    break;

                case TypeCode.Single:

                    switch (tc)

                    {

                        case TypeCode.Single:

                        case TypeCode.Double:

                            return true;

                    }

                    break;

                default:

                    if (st == tt)

                        return true;

                    break;

            }

            return false;

        }



        static bool IsBetterThan(Expression[] args, MethodData m1, MethodData m2)

        {

            bool better = false;

            for (int i = 0; i < args.Length; i++)

            {

                int c = CompareConversions(args[i].Type,

                    m1.Parameters[i].ParameterType,

                    m2.Parameters[i].ParameterType);

                if (c < 0)

                    return false;

                if (c > 0)

                    better = true;

            }

            return better;

        }



        // Return 1 if s -> t1 is a better conversion than s -> t2

        // Return -1 if s -> t2 is a better conversion than s -> t1

        // Return 0 if neither conversion is better

        static int CompareConversions(Type s, Type t1, Type t2)

        {

            if (t1 == t2)

                return 0;

            if (s == t1)

                return 1;

            if (s == t2)

                return -1;

            bool t1t2 = IsCompatibleWith(t1, t2);

            bool t2t1 = IsCompatibleWith(t2, t1);

            if (t1t2 && !t2t1)

                return 1;

            if (t2t1 && !t1t2)

                return -1;

            if (IsSignedIntegralType(t1) && IsUnsignedIntegralType(t2))

                return 1;

            if (IsSignedIntegralType(t2) && IsUnsignedIntegralType(t1))

                return -1;

            return 0;

        }



        static Expression GenerateEqual(Expression left, Expression right)

        {

            return Expression.Equal(left, right);

        }



        static Expression GenerateNotEqual(Expression left, Expression right)

        {

            return Expression.NotEqual(left, right);

        }



        static Expression GenerateGreaterThan(Expression left, Expression right)

        {

            if (left.Type == typeof(string))

            {

                return Expression.GreaterThan(

                    GenerateStaticMethodCall("Compare", left, right),

                    Expression.Constant(0)

                );

            }

            return Expression.GreaterThan(left, right);

        }



        static Expression GenerateGreaterThanEqual(Expression left, Expression right)

        {

            if (left.Type == typeof(string))

            {

                return Expression.GreaterThanOrEqual(

                    GenerateStaticMethodCall("Compare", left, right),

                    Expression.Constant(0)

                );

            }

            return Expression.GreaterThanOrEqual(left, right);

        }



        static Expression GenerateLessThan(Expression left, Expression right)

        {

            if (left.Type == typeof(string))

            {

                return Expression.LessThan(

                    GenerateStaticMethodCall("Compare", left, right),

                    Expression.Constant(0)

                );

            }

            return Expression.LessThan(left, right);

        }



        static Expression GenerateLessThanEqual(Expression left, Expression right)

        {

            if (left.Type == typeof(string))

            {

                return Expression.LessThanOrEqual(

                    GenerateStaticMethodCall("Compare", left, right),

                    Expression.Constant(0)

                );

            }

            return Expression.LessThanOrEqual(left, right);

        }



        static Expression GenerateAdd(Expression left, Expression right)

        {

            if (left.Type == typeof(string) && right.Type == typeof(string))

            {

                return GenerateStaticMethodCall("Concat", left, right);

            }

            return Expression.Add(left, right);

        }



        static Expression GenerateSubtract(Expression left, Expression right)

        {

            return Expression.Subtract(left, right);

        }



        static Expression GenerateStringConcat(Expression left, Expression right)

        {

            if (left.Type.IsValueType)

                left = Expression.Convert(left, typeof(object));

            if (right.Type.IsValueType)

                right = Expression.Convert(right, typeof(object));

            return Expression.Call(

                null,

                typeof(string).GetMethod("Concat", new[] { typeof(object), typeof(object) }),

                new[] { left, right });

        }



        static MethodInfo GetStaticMethod(string methodName, Expression left, Expression right)

        {

            return left.Type.GetMethod(methodName, new[] { left.Type, right.Type });

        }



        static Expression GenerateStaticMethodCall(string methodName, Expression left, Expression right)

        {

            return Expression.Call(null, GetStaticMethod(methodName, left, right), new[] { left, right });

        }



        void SetTextPos(int pos)

        {

            textPos = pos;

            ch = textPos < textLen ? text[textPos] : '\0';

        }



        void NextChar()

        {

            if (textPos < textLen)

                textPos++;

            ch = textPos < textLen ? text[textPos] : '\0';

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity", Justification = "Legacy code.")]

        void NextToken()

        {

            while (Char.IsWhiteSpace(ch))

                NextChar();

            TokenId t;

            int tokenPos = textPos;

            switch (ch)

            {

                case '%':

                    NextChar();

                    t = TokenId.Percent;

                    break;

                case '&':

                    NextChar();

                    if (ch == '&')

                    {

                        NextChar();

                        t = TokenId.DoubleAmphersand;

                    }

                    else

                    {

                        t = TokenId.Amphersand;

                    }

                    break;

                case '(':

                    NextChar();

                    t = TokenId.OpenParen;

                    break;

                case ')':

                    NextChar();

                    t = TokenId.CloseParen;

                    break;

                case ',':

                    NextChar();

                    t = TokenId.Comma;

                    break;

                case '/':

                    NextChar();

                    t = TokenId.Dot;

                    break;

                case ':':

                    NextChar();

                    t = TokenId.Colon;

                    break;

                case '?':

                    NextChar();

                    t = TokenId.Question;

                    break;

                case '[':

                    NextChar();

                    t = TokenId.OpenBracket;

                    break;

                case ']':

                    NextChar();

                    t = TokenId.CloseBracket;

                    break;

                case '|':

                    NextChar();

                    if (ch == '|')

                    {

                        NextChar();

                        t = TokenId.DoubleBar;

                    }

                    else

                    {

                        t = TokenId.Bar;

                    }

                    break;

                case '"':

                case '\'':

                    char quote = ch;

                    do

                    {

                        NextChar();

                        while (textPos < textLen && ch != quote)

                        {

                            if (ch == '\\')

                            {

                                NextChar();

                            }



                            NextChar();

                        }



                        if (textPos == textLen)

                            throw ParseError(textPos, SR.UnterminatedStringLiteral);

                        NextChar();

                    } while (ch == quote);

                    t = TokenId.StringLiteral;

                    break;

                default:

                    if (IsIdentifierStart(ch) || ch == '@' || ch == '_')

                    {

                        do

                        {

                            NextChar();

                        } while (IsIdentifierPart(ch) || ch == '_');

                        t = TokenId.Identifier;

                        break;

                    }

                    if (Char.IsDigit(ch))

                    {

                        t = TokenId.IntegerLiteral;

                        do

                        {

                            NextChar();

                        } while (Char.IsDigit(ch));

                        if (ch == '.')

                        {

                            t = TokenId.RealLiteral;

                            NextChar();

                            ValidateDigit();

                            do

                            {

                                NextChar();

                            } while (Char.IsDigit(ch));

                        }

                        if (ch == 'E' || ch == 'e')

                        {

                            t = TokenId.RealLiteral;

                            NextChar();

                            if (ch == '+' || ch == '-')

                                NextChar();

                            ValidateDigit();

                            do

                            {

                                NextChar();

                            } while (Char.IsDigit(ch));

                        }

                        if (ch == 'F' || ch == 'f' || ch == 'M' || ch == 'm' || ch == 'D' || ch == 'd')

                        {

                            t = TokenId.RealLiteral;

                            NextChar();

                        }

                        break;

                    }

                    if (textPos == textLen)

                    {

                        t = TokenId.End;

                        break;

                    }

                    throw ParseError(textPos, SR.InvalidCharacter(ch));

            }

            token.id = t;

            token.text = text.Substring(tokenPos, textPos - tokenPos);

            token.pos = tokenPos;



            token.id = ReclassifyToken(token);

        }



        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Maintainability", "CA1500:VariableNamesShouldNotMatchFieldNames", Justification = "Legacy code.")]

        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "Legacy code.")]

        TokenId ReclassifyToken(Token token)

        {

            if (token.id == TokenId.Identifier)

            {

                if (token.text == "add")

                {

                    return TokenId.Plus;

                }

                else if (token.text == "and")

                {

                    return TokenId.DoubleAmphersand;

                }

                else if (token.text == "div")

                {

                    return TokenId.Slash;

                }

                else if (token.text == "sub")

                {

                    return TokenId.Minus;

                }

                else if (token.text == "mul")

                {

                    return TokenId.Asterisk;

                }

                else if (token.text == "mod")

                {

                    return TokenId.Percent;

                }

                else if (token.text == "ne")

                {

                    return TokenId.ExclamationEqual;

                }

                else if (token.text == "not")

                {

                    return TokenId.Exclamation;

                }

                else if (token.text == "le")

                {

                    return TokenId.LessThanEqual;

                }

                else if (token.text == "lt")

                {

                    return TokenId.LessThan;

                }

                else if (token.text == "eq")

                {

                    return TokenId.DoubleEqual;

                }

                else if (token.text == "eq")

                {

                    return TokenId.DoubleEqual;

                }

                else if (token.text == "ge")

                {

                    return TokenId.GreaterThanEqual;

                }

                else if (token.text == "gt")

                {

                    return TokenId.GreaterThan;

                }

            }



            return token.id;

        }



        static bool IsIdentifierStart(char ch)

        {

            const int mask =

                1 << (int)UnicodeCategory.UppercaseLetter |

                1 << (int)UnicodeCategory.LowercaseLetter |

                1 << (int)UnicodeCategory.TitlecaseLetter |

                1 << (int)UnicodeCategory.ModifierLetter |

                1 << (int)UnicodeCategory.OtherLetter |

                1 << (int)UnicodeCategory.LetterNumber;

            return (1 << (int)Char.GetUnicodeCategory(ch) & mask) != 0;

        }



        static bool IsIdentifierPart(char ch)

        {

            const int mask =

                1 << (int)UnicodeCategory.UppercaseLetter |

                1 << (int)UnicodeCategory.LowercaseLetter |

                1 << (int)UnicodeCategory.TitlecaseLetter |

                1 << (int)UnicodeCategory.ModifierLetter |

                1 << (int)UnicodeCategory.OtherLetter |

                1 << (int)UnicodeCategory.LetterNumber |

                1 << (int)UnicodeCategory.DecimalDigitNumber |

                1 << (int)UnicodeCategory.ConnectorPunctuation |

                1 << (int)UnicodeCategory.NonSpacingMark |

                1 << (int)UnicodeCategory.SpacingCombiningMark |

                1 << (int)UnicodeCategory.Format;

            return (1 << (int)Char.GetUnicodeCategory(ch) & mask) != 0;

        }



        bool TokenIdentifierIs(string id)

        {

            return token.id == TokenId.Identifier && String.Equals(id, token.text, StringComparison.OrdinalIgnoreCase);

        }



        string GetIdentifier()

        {

            ValidateToken(TokenId.Identifier, SR.IdentifierExpected);

            string id = token.text;

            if (id.Length > 1 && id[0] == '@')

                id = id.Substring(1);

            return id;

        }



        void ValidateDigit()

        {

            if (!Char.IsDigit(ch))

                throw ParseError(textPos, SR.DigitExpected);

        }



        void ValidateToken(TokenId t, string errorMessage)

        {

            if (token.id != t)

                throw ParseError(errorMessage);

        }



        void ValidateToken(TokenId t)

        {

            if (token.id != t)

                throw ParseError(SR.SyntaxError);

        }



        Exception ParseError(string format, params object[] args)

        {

            return ParseError(token.pos, format, args);

        }



        static Exception ParseError(int pos, string format, params object[] args)

        {

            return new ParseException(string.Format(CultureInfo.CurrentCulture, format, args), pos);

        }



        static Dictionary<string, object> CreateKeywords()

        {

            Dictionary<string, object> d = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);

            d.Add("true", trueLiteral);

            d.Add("false", falseLiteral);

            d.Add("null", nullLiteral);

            d.Add(keywordIt, keywordIt);

            d.Add(keywordIif, keywordIif);

            foreach (Type type in predefinedTypes)

                d.Add(type.Name, type);

            return d;

        }

    }



}