C#.NET 动态Linq DynamicQueryable

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

using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Reflection.Emit;
using System.Threading;

namespace System.Linq.Dynamic
{
public static class DynamicQueryable
{
public static IQueryable<T> Where<T>(this IQueryable<T> source, string predicate, params object[] values) {
return (IQueryable<T>)Where((IQueryable)source, predicate, values);
}

public static IQueryable Where(this IQueryable source, string predicate, params object[] values) {
if (source == null) throw new ArgumentNullException("source");
if (predicate == null) throw new ArgumentNullException("predicate");
LambdaExpression lambda
= DynamicExpression.ParseLambda(source.ElementType, typeof(bool), predicate, values);
return source.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "Where",
new Type[] { source.ElementType },
source.Expression, Expression.Quote(lambda)));
}

public static IQueryable Select(this IQueryable source, string selector, params object[] values) {
if (source == null) throw new ArgumentNullException("source");
if (selector == null) throw new ArgumentNullException("selector");
LambdaExpression lambda
= DynamicExpression.ParseLambda(source.ElementType, null, selector, values);
return source.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "Select",
new Type[] { source.ElementType, lambda.Body.Type },
source.Expression, Expression.Quote(lambda)));
}

public static IQueryable<T> OrderBy<T>(this IQueryable<T> source, string ordering, params object[] values) {
return (IQueryable<T>)OrderBy((IQueryable)source, ordering, values);
}

public static IQueryable OrderBy(this IQueryable source, string ordering, params object[] values) {
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, values);
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(Expression.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)));
}

public static IQueryable GroupBy(this IQueryable source, string keySelector, string elementSelector, params object[] values) {
if (source == null) throw new ArgumentNullException("source");
if (keySelector == null) throw new ArgumentNullException("keySelector");
if (elementSelector == null) throw new ArgumentNullException("elementSelector");
LambdaExpression keyLambda
= DynamicExpression.ParseLambda(source.ElementType, null, keySelector, values);
LambdaExpression elementLambda
= DynamicExpression.ParseLambda(source.ElementType, null, elementSelector, values);
return source.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "GroupBy",
new Type[] { source.ElementType, keyLambda.Body.Type, elementLambda.Body.Type },
source.Expression, Expression.Quote(keyLambda), Expression.Quote(elementLambda)));
}

public static bool Any(this IQueryable source) {
if (source == null) throw new ArgumentNullException("source");
return (bool)source.Provider.Execute(
Expression.Call(
typeof(Queryable), "Any",
new Type[] { source.ElementType }, source.Expression));
}

public static int Count(this IQueryable source) {
if (source == null) throw new ArgumentNullException("source");
return (int)source.Provider.Execute(
Expression.Call(
typeof(Queryable), "Count",
new Type[] { source.ElementType }, source.Expression));
}
}

public abstract class DynamicClass
{
public override string ToString() {
PropertyInfo[] props
= this.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public);
StringBuilder sb
= new StringBuilder();
sb.Append(
"{");
for (int i = 0; i < props.Length; i++) {
if (i > 0) sb.Append(", ");
sb.Append(props[i].Name);
sb.Append(
"=");
sb.Append(props[i].GetValue(
this, null));
}
sb.Append(
"}");
return sb.ToString();
}
}

public class DynamicProperty
{
string name;
Type type;

public DynamicProperty(string name, Type type) {
if (name == null) throw new ArgumentNullException("name");
if (type == null) throw new ArgumentNullException("type");
this.name = name;
this.type = type;
}

public string Name {
get { return name; }
}

public Type Type {
get { return type; }
}
}

public static class DynamicExpression
{
public static Expression Parse(Type resultType, string expression, params object[] values) {
ExpressionParser parser
= new ExpressionParser(null, expression, values);
return parser.Parse(resultType);
}

public static LambdaExpression ParseLambda(Type itType, Type resultType, string expression, params object[] values) {
return ParseLambda(new ParameterExpression[] { Expression.Parameter(itType, "") }, resultType, expression, values);
}

public static LambdaExpression ParseLambda(ParameterExpression[] parameters, Type resultType, string expression, params object[] values) {
ExpressionParser parser
= new ExpressionParser(parameters, expression, values);
return Expression.Lambda(parser.Parse(resultType), parameters);
}

public static Expression<Func<T, S>> ParseLambda<T, S>(string expression, params object[] values) {
return (Expression<Func<T, S>>)ParseLambda(typeof(T), typeof(S), expression, values);
}

public static Type CreateClass(params DynamicProperty[] properties) {
return ClassFactory.Instance.GetDynamicClass(properties);
}

public static Type CreateClass(IEnumerable<DynamicProperty> properties) {
return ClassFactory.Instance.GetDynamicClass(properties);
}
}

internal class DynamicOrdering
{
public Expression Selector;
public bool Ascending;
}

internal class Signature : IEquatable<Signature>
{
public DynamicProperty[] properties;
public int hashCode;

public Signature(IEnumerable<DynamicProperty> properties) {
this.properties = properties.ToArray();
hashCode
= 0;
foreach (DynamicProperty p in properties) {
hashCode
^= p.Name.GetHashCode() ^ p.Type.GetHashCode();
}
}

public override int GetHashCode() {
return hashCode;
}

public override bool Equals(object obj) {
return obj is Signature ? Equals((Signature)obj) : false;
}

public bool Equals(Signature other) {
if (properties.Length != other.properties.Length) return false;
for (int i = 0; i < properties.Length; i++) {
if (properties[i].Name != other.properties[i].Name ||
properties[i].Type
!= other.properties[i].Type) return false;
}
return true;
}
}

internal class ClassFactory
{
public static readonly ClassFactory Instance = new ClassFactory();

static ClassFactory() { } // Trigger lazy initialization of static fields

ModuleBuilder module;
Dictionary
<Signature, Type> classes;
int classCount;
ReaderWriterLock rwLock;

private ClassFactory() {
AssemblyName name
= new AssemblyName("DynamicClasses");
AssemblyBuilder assembly
= AppDomain.CurrentDomain.DefineDynamicAssembly(name, AssemblyBuilderAccess.Run);
#if ENABLE_LINQ_PARTIAL_TRUST
new ReflectionPermission(PermissionState.Unrestricted).Assert();
#endif
try {
module
= assembly.DefineDynamicModule("Module");
}
finally {
#if ENABLE_LINQ_PARTIAL_TRUST
PermissionSet.RevertAssert();
#endif
}
classes
= new Dictionary<Signature, Type>();
rwLock
= new ReaderWriterLock();
}

public Type GetDynamicClass(IEnumerable<DynamicProperty> properties) {
rwLock.AcquireReaderLock(Timeout.Infinite);
try {
Signature signature
= new Signature(properties);
Type type;
if (!classes.TryGetValue(signature, out type)) {
type
= CreateDynamicClass(signature.properties);
classes.Add(signature, type);
}
return type;
}
finally {
rwLock.ReleaseReaderLock();
}
}

Type CreateDynamicClass(DynamicProperty[] properties) {
LockCookie cookie
= rwLock.UpgradeToWriterLock(Timeout.Infinite);
try {
string typeName = "DynamicClass" + (classCount + 1);
#if ENABLE_LINQ_PARTIAL_TRUST
new ReflectionPermission(PermissionState.Unrestricted).Assert();
#endif
try {
TypeBuilder tb
= this.module.DefineType(typeName, TypeAttributes.Class |
TypeAttributes.Public,
typeof(DynamicClass));
FieldInfo[] fields
= GenerateProperties(tb, properties);
GenerateEquals(tb, fields);
GenerateGetHashCode(tb, fields);
Type result
= tb.CreateType();
classCount
++;
return result;
}
finally {
#if ENABLE_LINQ_PARTIAL_TRUST
PermissionSet.RevertAssert();
#endif
}
}
finally {
rwLock.DowngradeFromWriterLock(
ref cookie);
}
}

FieldInfo[] GenerateProperties(TypeBuilder tb, DynamicProperty[] properties) {
FieldInfo[] fields
= new FieldBuilder[properties.Length];
for (int i = 0; i < properties.Length; i++) {
DynamicProperty dp
= properties[i];
FieldBuilder fb
= tb.DefineField("_" + dp.Name, dp.Type, FieldAttributes.Private);
PropertyBuilder pb
= tb.DefineProperty(dp.Name, PropertyAttributes.HasDefault, dp.Type, null);
MethodBuilder mbGet
= tb.DefineMethod("get_" + dp.Name,
MethodAttributes.Public
| MethodAttributes.SpecialName | MethodAttributes.HideBySig,
dp.Type, Type.EmptyTypes);
ILGenerator genGet
= mbGet.GetILGenerator();
genGet.Emit(OpCodes.Ldarg_0);
genGet.Emit(OpCodes.Ldfld, fb);
genGet.Emit(OpCodes.Ret);
MethodBuilder mbSet
= tb.DefineMethod("set_" + dp.Name,
MethodAttributes.Public
| MethodAttributes.SpecialName | MethodAttributes.HideBySig,
null, new Type[] { dp.Type });
ILGenerator genSet
= mbSet.GetILGenerator();
genSet.Emit(OpCodes.Ldarg_0);
genSet.Emit(OpCodes.Ldarg_1);
genSet.Emit(OpCodes.Stfld, fb);
genSet.Emit(OpCodes.Ret);
pb.SetGetMethod(mbGet);
pb.SetSetMethod(mbSet);
fields[i]
= fb;
}
return fields;
}

void GenerateEquals(TypeBuilder tb, FieldInfo[] fields) {
MethodBuilder mb
= tb.DefineMethod("Equals",
MethodAttributes.Public
| MethodAttributes.ReuseSlot |
MethodAttributes.Virtual
| MethodAttributes.HideBySig,
typeof(bool), new Type[] { typeof(object) });
ILGenerator gen
= mb.GetILGenerator();
LocalBuilder other
= gen.DeclareLocal(tb);
Label next
= gen.DefineLabel();
gen.Emit(OpCodes.Ldarg_1);
gen.Emit(OpCodes.Isinst, tb);
gen.Emit(OpCodes.Stloc, other);
gen.Emit(OpCodes.Ldloc, other);
gen.Emit(OpCodes.Brtrue_S, next);
gen.Emit(OpCodes.Ldc_I4_0);
gen.Emit(OpCodes.Ret);
gen.MarkLabel(next);
foreach (FieldInfo field in fields) {
Type ft
= field.FieldType;
Type ct
= typeof(EqualityComparer<>).MakeGenericType(ft);
next
= gen.DefineLabel();
gen.EmitCall(OpCodes.Call, ct.GetMethod(
"get_Default"), null);
gen.Emit(OpCodes.Ldarg_0);
gen.Emit(OpCodes.Ldfld, field);
gen.Emit(OpCodes.Ldloc, other);
gen.Emit(OpCodes.Ldfld, field);
gen.EmitCall(OpCodes.Callvirt, ct.GetMethod(
"Equals", new Type[] { ft, ft }), null);
gen.Emit(OpCodes.Brtrue_S, next);
gen.Emit(OpCodes.Ldc_I4_0);
gen.Emit(OpCodes.Ret);
gen.MarkLabel(next);
}
gen.Emit(OpCodes.Ldc_I4_1);
gen.Emit(OpCodes.Ret);
}

void GenerateGetHashCode(TypeBuilder tb, FieldInfo[] fields) {
MethodBuilder mb
= tb.DefineMethod("GetHashCode",
MethodAttributes.Public
| MethodAttributes.ReuseSlot |
MethodAttributes.Virtual
| MethodAttributes.HideBySig,
typeof(int), Type.EmptyTypes);
ILGenerator gen
= mb.GetILGenerator();
gen.Emit(OpCodes.Ldc_I4_0);
foreach (FieldInfo field in fields) {
Type ft
= field.FieldType;
Type ct
= typeof(EqualityComparer<>).MakeGenericType(ft);
gen.EmitCall(OpCodes.Call, ct.GetMethod(
"get_Default"), null);
gen.Emit(OpCodes.Ldarg_0);
gen.Emit(OpCodes.Ldfld, field);
gen.EmitCall(OpCodes.Callvirt, ct.GetMethod(
"GetHashCode", new Type[] { ft }), null);
gen.Emit(OpCodes.Xor);
}
gen.Emit(OpCodes.Ret);
}
}

public sealed class ParseException : Exception
{
int position;

public ParseException(string message, int position)
:
base(message) {
this.position = position;
}

public int Position {
get { return position; }
}

public override string ToString() {
return string.Format(Res.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
}

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);
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);
}

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);
}

interface IEqualitySignatures : IRelationalSignatures
{
void F(bool x, bool y);
void F(bool? x, bool? 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);
}

interface ISubtractSignatures : IAddSignatures
{
void F(DateTime x, DateTime y);
void F(DateTime? x, DateTime? 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(TimeSpan),
typeof(Guid),
typeof(Math),
typeof(Convert)
};

static readonly Expression trueLiteral = Expression.Constant(true);
static readonly Expression falseLiteral = Expression.Constant(false);
static readonly Expression nullLiteral = Expression.Constant(null);

static readonly string keywordIt = "it";
static readonly string keywordIif = "iif";
static readonly string keywordNew = "new";

static Dictionary<string, object> keywords;

Dictionary
<string, object> symbols;
IDictionary
<string, object> externals;
Dictionary
<Expression, string> literals;
ParameterExpression it;
string text;
int textPos;
int textLen;
char ch;
Token token;

public ExpressionParser(ParameterExpression[] parameters, string expression, object[] values) {
if (expression == null) throw new ArgumentNullException("expression");
if (keywords == null) keywords = CreateKeywords();
symbols
= new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
literals
= new Dictionary<Expression, string>();
if (parameters != null) ProcessParameters(parameters);
if (values != null) ProcessValues(values);
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 ProcessValues(object[] values) {
for (int i = 0; i < values.Length; i++) {
object value = values[i];
if (i == values.Length - 1 && value is IDictionary<string, object>) {
externals
= (IDictionary<string, object>)value;
}
else {
AddSymbol(
"@" + i.ToString(System.Globalization.CultureInfo.InvariantCulture), value);
}
}
}

void AddSymbol(string name, object value) {
if (symbols.ContainsKey(name))
throw ParseError(Res.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, Res.ExpressionTypeMismatch, GetTypeName(resultType));
ValidateToken(TokenId.End, Res.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, Res.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, Res.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;
}

// =, ==, !=, <>, >, >=, <, <= 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)) {
if (left.Type != right.Type) {
Expression e;
if ((e = PromoteExpression(right, left.Type, true)) != null) {
right
= e;
}
else if ((e = PromoteExpression(left, right.Type, true)) != null) {
left
= e;
}
else {
throw IncompatibleOperandsError(op.text, left, 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;
}

// +, -, & 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(Res.ExpressionExpected);
}
}

Expression ParseStringLiteral() {
ValidateToken(TokenId.StringLiteral);
char quote = token.text[0];
string s = token.text.Substring(1, token.text.Length - 2);
int start = 0;
while (true) {
int i = s.IndexOf(quote, start);
if (i < 0) break;
s
= s.Remove(i, 1);
start
= i + 1;
}
if (quote == '\'') {
if (s.Length != 1)
throw ParseError(Res.InvalidCharacterLiteral);
NextToken();
return CreateLiteral(s[0], s);
}
NextToken();
return CreateLiteral(s, s);
}

Expression ParseIntegerLiteral() {
ValidateToken(TokenId.IntegerLiteral);
string text = token.text;
if (text[0] != '-') {
ulong value;
if (!UInt64.TryParse(text, out value))
throw ParseError(Res.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, out value))
throw ParseError(Res.InvalidIntegerLiteral, text);
NextToken();
if (value >= Int32.MinValue && value <= Int32.MaxValue)
return CreateLiteral((int)value, text);
return CreateLiteral(value, text);
}
}

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), out f)) value = f;
}
else {
double d;
if (Double.TryParse(text, out d)) value = d;
}
if (value == null) throw ParseError(Res.InvalidRealLiteral, text);
NextToken();
return CreateLiteral(value, text);
}

Expression CreateLiteral(
object value, string text) {
ConstantExpression expr
= Expression.Constant(value);
literals.Add(expr, text);
return expr;
}

Expression ParseParenExpression() {
ValidateToken(TokenId.OpenParen, Res.OpenParenExpected);
NextToken();
Expression e
= ParseExpression();
ValidateToken(TokenId.CloseParen, Res.CloseParenOrOperatorExpected);
NextToken();
return e;
}

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();
if (value == (object)keywordNew) return ParseNew();
NextToken();
return (Expression)value;
}
if (symbols.TryGetValue(token.text, out value) ||
externals
!= null && externals.TryGetValue(token.text, out value)) {
Expression expr
= value as Expression;
if (expr == null) {
expr
= Expression.Constant(value);
}
else {
LambdaExpression lambda
= expr as LambdaExpression;
if (lambda != null) return ParseLambdaInvocation(lambda);
}
NextToken();
return expr;
}
if (it != null) return ParseMemberAccess(null, it);
throw ParseError(Res.UnknownIdentifier, token.text);
}

Expression ParseIt() {
if (it == null)
throw ParseError(Res.NoItInScope);
NextToken();
return it;
}

Expression ParseIif() {
int errorPos = token.pos;
NextToken();
Expression[] args
= ParseArgumentList();
if (args.Length != 3)
throw ParseError(errorPos, Res.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, Res.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, Res.BothTypesConvertToOther, type1, type2);
throw ParseError(errorPos, Res.NeitherTypeConvertsToOther, type1, type2);
}
}
return Expression.Condition(test, expr1, expr2);
}

Expression ParseNew() {
NextToken();
ValidateToken(TokenId.OpenParen, Res.OpenParenExpected);
NextToken();
List
<DynamicProperty> properties = new List<DynamicProperty>();
List
<Expression> expressions = new List<Expression>();
while (true) {
int exprPos = token.pos;
Expression expr
= ParseExpression();
string propName;
if (TokenIdentifierIs("as")) {
NextToken();
propName
= GetIdentifier();
NextToken();
}
else {
MemberExpression me
= expr as MemberExpression;
if (me == null) throw ParseError(exprPos, Res.MissingAsClause);
propName
= me.Member.Name;
}
expressions.Add(expr);
properties.Add(
new DynamicProperty(propName, expr.Type));
if (token.id != TokenId.Comma) break;
NextToken();
}
ValidateToken(TokenId.CloseParen, Res.CloseParenOrCommaExpected);
NextToken();
Type type
= DynamicExpression.CreateClass(properties);
MemberBinding[] bindings
= new MemberBinding[properties.Count];
for (int i = 0; i < bindings.Length; i++)
bindings[i]
= Expression.Bind(type.GetProperty(properties[i].Name), expressions[i]);
return Expression.MemberInit(Expression.New(type), bindings);
}

Expression ParseLambdaInvocation(LambdaExpression lambda) {
int errorPos = token.pos;
NextToken();
Expression[] args
= ParseArgumentList();
MethodBase method;
if (FindMethod(lambda.Type, "Invoke", false, args, out method) != 1)
throw ParseError(errorPos, Res.ArgsIncompatibleWithLambda);
return Expression.Invoke(lambda, args);
}

Expression ParseTypeAccess(Type type) {
int errorPos = token.pos;
NextToken();
if (token.id == TokenId.Question) {
if (!type.IsValueType || IsNullableType(type))
throw ParseError(errorPos, Res.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, Res.NoMatchingConstructor, GetTypeName(type));
case 1:
return Expression.New((ConstructorInfo)method, args);
default:
throw ParseError(errorPos, Res.AmbiguousConstructorInvocation, GetTypeName(type));
}
}
ValidateToken(TokenId.Dot, Res.DotOrOpenParenExpected);
NextToken();
return ParseMemberAccess(type, null);
}

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, Res.CannotConvertValue,
GetTypeName(exprType), GetTypeName(type));
}

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, Res.NoApplicableMethod,
id, GetTypeName(type));
case 1:
MethodInfo method
= (MethodInfo)mb;
if (!IsPredefinedType(method.DeclaringType))
throw ParseError(errorPos, Res.MethodsAreInaccessible, GetTypeName(method.DeclaringType));
if (method.ReturnType == typeof(void))
throw ParseError(errorPos, Res.MethodIsVoid,
id, GetTypeName(method.DeclaringType));
return Expression.Call(instance, (MethodInfo)method, args);
default:
throw ParseError(errorPos, Res.AmbiguousMethodInvocation,
id, GetTypeName(type));
}
}
else {
MemberInfo member
= FindPropertyOrField(type, id, instance == null);
if (member == null)
throw ParseError(errorPos, Res.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, Res.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, Expression.Lambda(args[0], innerIt) };
}
return Expression.Call(typeof(Enumerable), signature.Name, typeArgs, args);
}

Expression[] ParseArgumentList() {
ValidateToken(TokenId.OpenParen, Res.OpenParenExpected);
NextToken();
Expression[] args
= token.id != TokenId.CloseParen ? ParseArguments() : new Expression[0];
ValidateToken(TokenId.CloseParen, Res.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, Res.OpenParenExpected);
NextToken();
Expression[] args
= ParseArguments();
ValidateToken(TokenId.CloseBracket, Res.CloseBracketOrCommaExpected);
NextToken();
if (expr.Type.IsArray) {
if (expr.Type.GetArrayRank() != 1 || args.Length != 1)
throw ParseError(errorPos, Res.CannotIndexMultiDimArray);
Expression index
= PromoteExpression(args[0], typeof(int), true);
if (index == null)
throw ParseError(errorPos, Res.InvalidIndex);
return Expression.ArrayIndex(expr, index);
}
else {
MethodBase mb;
switch (FindIndexer(expr.Type, args, out mb)) {
case 0:
throw ParseError(errorPos, Res.NoApplicableIndexer,
GetTypeName(expr.Type));
case 1:
return Expression.Call(expr, (MethodInfo)mb, args);
default:
throw ParseError(errorPos, Res.AmbiguousIndexerInvocation,
GetTypeName(expr.Type));
}
}
}

static bool IsPredefinedType(Type 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;
}

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, Res.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];
}

Exception IncompatibleOperandsError(
string opName, Expression left, Expression right, int pos) {
return ParseError(pos, Res.IncompatibleOperands,
opName, GetTypeName(left.Type), GetTypeName(right.Type));
}

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;
}

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:
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, out sb)) return sb;
break;
case TypeCode.Byte:
byte b;
if (byte.TryParse(text, out b)) return b;
break;
case TypeCode.Int16:
short s;
if (short.TryParse(text, out s)) return s;
break;
case TypeCode.UInt16:
ushort us;
if (ushort.TryParse(text, out us)) return us;
break;
case TypeCode.Int32:
int i;
if (int.TryParse(text, out i)) return i;
break;
case TypeCode.UInt32:
uint ui;
if (uint.TryParse(text, out ui)) return ui;
break;
case TypeCode.Int64:
long l;
if (long.TryParse(text, out l)) return l;
break;
case TypeCode.UInt64:
ulong ul;
if (ulong.TryParse(text, out ul)) return ul;
break;
case TypeCode.Single:
float f;
if (float.TryParse(text, out f)) return f;
break;
case TypeCode.Double:
double d;
if (double.TryParse(text, out d)) return d;
break;
case TypeCode.Decimal:
decimal e;
if (decimal.TryParse(text, 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;
}

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;
}

Expression GenerateEqual(Expression left, Expression right) {
return Expression.Equal(left, right);
}

Expression GenerateNotEqual(Expression left, Expression right) {
return Expression.NotEqual(left, right);
}

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);
}

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);
}

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);
}

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);
}

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);
}

Expression GenerateSubtract(Expression left, Expression right) {
return Expression.Subtract(left, right);
}

Expression GenerateStringConcat(Expression left, Expression right) {
return Expression.Call(
null,
typeof(string).GetMethod("Concat", new[] { typeof(object), typeof(object) }),
new[] { left, right });
}

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

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';
}

void NextToken() {
while (Char.IsWhiteSpace(ch)) NextChar();
TokenId t;
int tokenPos = textPos;
switch (ch) {
case '!':
NextChar();
if (ch == '=') {
NextChar();
t
= TokenId.ExclamationEqual;
}
else {
t
= TokenId.Exclamation;
}
break;
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.Asterisk;
break;
case '+':
NextChar();
t
= TokenId.Plus;
break;
case ',':
NextChar();
t
= TokenId.Comma;
break;
case '-':
NextChar();
t
= TokenId.Minus;
break;
case '.':
NextChar();
t
= TokenId.Dot;
break;
case '/':
NextChar();
t
= TokenId.Slash;
break;
case ':':
NextChar();
t
= TokenId.Colon;
break;
case '<':
NextChar();
if (ch == '=') {
NextChar();
t
= TokenId.LessThanEqual;
}
else if (ch == '>') {
NextChar();
t
= TokenId.LessGreater;
}
else {
t
= TokenId.LessThan;
}
break;
case '=':
NextChar();
if (ch == '=') {
NextChar();
t
= TokenId.DoubleEqual;
}
else {
t
= TokenId.Equal;
}
break;
case '>':
NextChar();
if (ch == '=') {
NextChar();
t
= TokenId.GreaterThanEqual;
}
else {
t
= TokenId.GreaterThan;
}
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) NextChar();
if (textPos == textLen)
throw ParseError(textPos, Res.UnterminatedStringLiteral);
NextChar();
}
while (ch == quote);
t
= TokenId.StringLiteral;
break;
default:
if (Char.IsLetter(ch) || ch == '@' || ch == '_') {
do {
NextChar();
}
while (Char.IsLetterOrDigit(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') NextChar();
break;
}
if (textPos == textLen) {
t
= TokenId.End;
break;
}
throw ParseError(textPos, Res.InvalidCharacter, ch);
}
token.id
= t;
token.text
= text.Substring(tokenPos, textPos - tokenPos);
token.pos
= tokenPos;
}

bool TokenIdentifierIs(string id) {
return token.id == TokenId.Identifier && String.Equals(id, token.text, StringComparison.OrdinalIgnoreCase);
}

string GetIdentifier() {
ValidateToken(TokenId.Identifier, Res.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, Res.DigitExpected);
}

void ValidateToken(TokenId t, string errorMessage) {
if (token.id != t) throw ParseError(errorMessage);
}

void ValidateToken(TokenId t) {
if (token.id != t) throw ParseError(Res.SyntaxError);
}

Exception ParseError(
string format, params object[] args) {
return ParseError(token.pos, format, args);
}

Exception ParseError(
int pos, string format, params object[] args) {
return new ParseException(string.Format(System.Globalization.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);
d.Add(keywordNew, keywordNew);
foreach (Type type in predefinedTypes) d.Add(type.Name, type);
return d;
}
}

static class Res
{
public const string DuplicateIdentifier = "The identifier '{0}' was defined more than once";
public const string ExpressionTypeMismatch = "Expression of type '{0}' expected";
public const string ExpressionExpected = "Expression expected";
public const string InvalidCharacterLiteral = "Character literal must contain exactly one character";
public const string InvalidIntegerLiteral = "Invalid integer literal '{0}'";
public const string InvalidRealLiteral = "Invalid real literal '{0}'";
public const string UnknownIdentifier = "Unknown identifier '{0}'";
public const string NoItInScope = "No 'it' is in scope";
public const string IifRequiresThreeArgs = "The 'iif' function requires three arguments";
public const string FirstExprMustBeBool = "The first expression must be of type 'Boolean'";
public const string BothTypesConvertToOther = "Both of the types '{0}' and '{1}' convert to the other";
public const string NeitherTypeConvertsToOther = "Neither of the types '{0}' and '{1}' converts to the other";
public const string MissingAsClause = "Expression is missing an 'as' clause";
public const string ArgsIncompatibleWithLambda = "Argument list incompatible with lambda expression";
public const string TypeHasNoNullableForm = "Type '{0}' has no nullable form";
public const string NoMatchingConstructor = "No matching constructor in type '{0}'";
public const string AmbiguousConstructorInvocation = "Ambiguous invocation of '{0}' constructor";
public const string CannotConvertValue = "A value of type '{0}' cannot be converted to type '{1}'";
public const string NoApplicableMethod = "No applicable method '{0}' exists in type '{1}'";
public const string MethodsAreInaccessible = "Methods on type '{0}' are not accessible";
public const string MethodIsVoid = "Method '{0}' in type '{1}' does not return a value";
public const string AmbiguousMethodInvocation = "Ambiguous invocation of method '{0}' in type '{1}'";
public const string UnknownPropertyOrField = "No property or field '{0}' exists in type '{1}'";
public const string NoApplicableAggregate = "No applicable aggregate method '{0}' exists";
public const string CannotIndexMultiDimArray = "Indexing of multi-dimensional arrays is not supported";
public const string InvalidIndex = "Array index must be an integer expression";
public const string NoApplicableIndexer = "No applicable indexer exists in type '{0}'";
public const string AmbiguousIndexerInvocation = "Ambiguous invocation of indexer in type '{0}'";
public const string IncompatibleOperand = "Operator '{0}' incompatible with operand type '{1}'";
public const string IncompatibleOperands = "Operator '{0}' incompatible with operand types '{1}' and '{2}'";
public const string UnterminatedStringLiteral = "Unterminated string literal";
public const string InvalidCharacter = "Syntax error '{0}'";
public const string DigitExpected = "Digit expected";
public const string SyntaxError = "Syntax error";
public const string TokenExpected = "{0} expected";
public const string ParseExceptionFormat = "{0} (at index {1})";
public const string ColonExpected = "':' expected";
public const string OpenParenExpected = "'(' expected";
public const string CloseParenOrOperatorExpected = "')' or operator expected";
public const string CloseParenOrCommaExpected = "')' or ',' expected";
public const string DotOrOpenParenExpected = "'.' or '(' expected";
public const string OpenBracketExpected = "'[' expected";
public const string CloseBracketOrCommaExpected = "']' or ',' expected";
public const string IdentifierExpected = "Identifier expected";
}

//var query = db.Customers.Where("City == @0 and Orders.Count >= @1", "London", 10).OrderBy("CompanyName").Select("New(CompanyName as Name, Phone)");
}

 

posted @ 2010-07-12 20:50  熊哥  阅读(8354)  评论(1编辑  收藏