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ExpressionParser.cs
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using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq.Dynamic.Core.Exceptions;
using System.Linq.Dynamic.Core.Parser.SupportedMethods;
using System.Linq.Dynamic.Core.Parser.SupportedOperands;
using System.Linq.Dynamic.Core.Tokenizer;
using System.Linq.Dynamic.Core.TypeConverters;
using System.Linq.Dynamic.Core.Validation;
using System.Linq.Expressions;
using System.Reflection;
using AnyOfTypes;
namespace System.Linq.Dynamic.Core.Parser;
/// <summary>
/// ExpressionParser
/// </summary>
public class ExpressionParser
{
private static readonly string[] OutKeywords = { "out", "$out" };
private const string DiscardVariable = "_";
private const string MethodOrderBy = nameof(Queryable.OrderBy);
private const string MethodOrderByDescending = nameof(Queryable.OrderByDescending);
private const string MethodThenBy = nameof(Queryable.ThenBy);
private const string MethodThenByDescending = nameof(Queryable.ThenByDescending);
private readonly ParsingConfig _parsingConfig;
private readonly MethodFinder _methodFinder;
private readonly IKeywordsHelper _keywordsHelper;
private readonly TextParser _textParser;
private readonly NumberParser _numberParser;
private readonly IExpressionHelper _expressionHelper;
private readonly ConstantExpressionHelper _constantExpressionHelper;
private readonly ITypeFinder _typeFinder;
private readonly ITypeConverterFactory _typeConverterFactory;
private readonly Dictionary<string, object> _internals = new();
private readonly Dictionary<string, object?> _symbols;
private IDictionary<string, object>? _externals;
private ParameterExpression? _it;
private ParameterExpression? _parent;
private ParameterExpression? _root;
private Type? _resultType;
private bool _createParameterCtor;
/// <summary>
/// Gets name for the `it` field. By default this is set to the KeyWord value "it".
/// </summary>
public string ItName { get; private set; } = KeywordsHelper.KEYWORD_IT;
/// <summary>
/// There was a problem when an expression contained multiple lambdas where
/// the ItName was not cleared and freed for the next lambda. This variable
/// stores the ItName of the last parsed lambda.
/// Not used internally by ExpressionParser, but used to preserve compatibility of parsingConfig.RenameParameterExpression
/// which was designed to only work with mono-lambda expressions.
/// </summary>
public string LastLambdaItName { get; private set; } = KeywordsHelper.KEYWORD_IT;
/// <summary>
/// Initializes a new instance of the <see cref="ExpressionParser"/> class.
/// </summary>
/// <param name="parameters">The parameters.</param>
/// <param name="expression">The expression.</param>
/// <param name="values">The values.</param>
/// <param name="parsingConfig">The parsing configuration.</param>
public ExpressionParser(ParameterExpression[]? parameters, string expression, object?[]? values, ParsingConfig? parsingConfig)
{
Check.NotEmpty(expression, nameof(expression));
_symbols = new Dictionary<string, object?>(parsingConfig is { IsCaseSensitive: true } ? StringComparer.Ordinal : StringComparer.OrdinalIgnoreCase);
_parsingConfig = parsingConfig ?? ParsingConfig.Default;
_keywordsHelper = new KeywordsHelper(_parsingConfig);
_textParser = new TextParser(_parsingConfig, expression);
_numberParser = new NumberParser(parsingConfig);
_expressionHelper = new ExpressionHelper(_parsingConfig);
_methodFinder = new MethodFinder(_parsingConfig, _expressionHelper);
_typeFinder = new TypeFinder(_parsingConfig, _keywordsHelper);
_typeConverterFactory = new TypeConverterFactory(_parsingConfig);
_constantExpressionHelper = ConstantExpressionHelperFactory.GetInstance(_parsingConfig);
if (parameters != null)
{
ProcessParameters(parameters);
}
if (values != null)
{
ProcessValues(values);
}
}
private void ProcessParameters(ParameterExpression[] parameters)
{
foreach (ParameterExpression pe in parameters.Where(p => !string.IsNullOrEmpty(p.Name)))
{
AddSymbol(pe.Name!, pe);
}
// If there is only 1 ParameterExpression, do also allow access using 'it'
if (parameters.Length == 1)
{
_parent = _it;
_it = parameters[0];
if (_root == null)
{
_root = _it;
}
}
}
private void ProcessValues(object?[] values)
{
for (int i = 0; i < values.Length; i++)
{
object? value = values[i];
IDictionary<string, object>? externals;
if (i == values.Length - 1 && (externals = value as IDictionary<string, object>) != null)
{
_externals = externals;
}
else
{
AddSymbol("@" + i.ToString(CultureInfo.InvariantCulture), value);
}
}
}
private void AddSymbol(string name, object? value)
{
if (_symbols.ContainsKey(name))
{
throw ParseError(Res.DuplicateIdentifier, name);
}
_symbols.Add(name, value);
}
/// <summary>
/// Uses the TextParser to parse the string into the specified result type.
/// </summary>
/// <param name="resultType">Type of the result.</param>
/// <param name="createParameterCtor">if set to <c>true</c> [create parameter ctor].</param>
/// <returns>Expression</returns>
public Expression Parse(Type? resultType, bool createParameterCtor = true)
{
_resultType = resultType;
_createParameterCtor = createParameterCtor;
int exprPos = _textParser.CurrentToken.Pos;
Expression? expr = ParseConditionalOperator();
if (resultType != null)
{
if ((expr = _parsingConfig.ExpressionPromoter.Promote(expr, resultType, true, false)) == null)
{
throw ParseError(exprPos, Res.ExpressionTypeMismatch, TypeHelper.GetTypeName(resultType));
}
}
_textParser.ValidateToken(TokenId.End, Res.SyntaxError);
return expr;
}
// out keyword
private Expression ParseOutKeyword()
{
if (_textParser.CurrentToken.Id == TokenId.Identifier && OutKeywords.Contains(_textParser.CurrentToken.Text))
{
// Go to next token (which should be a '_')
_textParser.NextToken();
var variableName = _textParser.CurrentToken.Text;
if (variableName != DiscardVariable)
{
throw ParseError(_textParser.CurrentToken.Pos, Res.OutKeywordRequiresDiscard);
}
// Advance to next token
_textParser.NextToken();
// Use MakeByRefType() to indicate that it's a by-reference type because C# uses this for both 'ref' and 'out' parameters.
// The "typeof(object).MakeByRefType()" is used, this will be changed later in the flow to the real type.
return Expression.Parameter(typeof(object).MakeByRefType(), variableName);
}
return ParseConditionalOperator();
}
internal IList<DynamicOrdering> ParseOrdering(bool forceThenBy = false)
{
var orderings = new List<DynamicOrdering>();
while (true)
{
Expression expr = ParseConditionalOperator();
bool ascending = true;
if (TokenIdentifierIs("asc") || TokenIdentifierIs("ascending"))
{
_textParser.NextToken();
}
else if (TokenIdentifierIs("desc") || TokenIdentifierIs("descending"))
{
_textParser.NextToken();
ascending = false;
}
string methodName;
if (forceThenBy || orderings.Count > 0)
{
methodName = ascending ? MethodThenBy : MethodThenByDescending;
}
else
{
methodName = ascending ? MethodOrderBy : MethodOrderByDescending;
}
orderings.Add(new DynamicOrdering { Selector = expr, Ascending = ascending, MethodName = methodName });
if (_textParser.CurrentToken.Id != TokenId.Comma)
{
break;
}
_textParser.NextToken();
}
_textParser.ValidateToken(TokenId.End, Res.SyntaxError);
return orderings;
}
// ?: operator
private Expression ParseConditionalOperator()
{
int errorPos = _textParser.CurrentToken.Pos;
Expression expr = ParseNullCoalescingOperator();
if (_textParser.CurrentToken.Id == TokenId.Question)
{
_textParser.NextToken();
Expression expr1 = ParseConditionalOperator();
_textParser.ValidateToken(TokenId.Colon, Res.ColonExpected);
_textParser.NextToken();
Expression expr2 = ParseConditionalOperator();
expr = GenerateConditional(expr, expr1, expr2, false, errorPos);
}
return expr;
}
// ?? (null-coalescing) operator
private Expression ParseNullCoalescingOperator()
{
Expression expr = ParseLambdaOperator();
if (_textParser.CurrentToken.Id == TokenId.NullCoalescing)
{
_textParser.NextToken();
Expression right = ParseConditionalOperator();
expr = Expression.Coalesce(expr, right);
}
return expr;
}
// => operator - Added Support for projection operator
private Expression ParseLambdaOperator()
{
Expression expr = ParseOrOperator();
if (_textParser.CurrentToken.Id == TokenId.Lambda && _it?.Type == expr.Type)
{
_textParser.NextToken();
if (_textParser.CurrentToken.Id == TokenId.Identifier || _textParser.CurrentToken.Id == TokenId.OpenParen)
{
var right = ParseConditionalOperator();
return Expression.Lambda(right, new[] { (ParameterExpression)expr });
}
_textParser.ValidateToken(TokenId.OpenParen, Res.OpenParenExpected);
}
return expr;
}
// Or operator
// - ||
// - Or
// - OrElse
private Expression ParseOrOperator()
{
Expression left = ParseAndOperator();
while (_textParser.CurrentToken.Id == TokenId.DoubleBar)
{
Token op = _textParser.CurrentToken;
_textParser.NextToken();
Expression right = ParseAndOperator();
CheckAndPromoteOperands(typeof(ILogicalSignatures), op.Id, op.Text, ref left, ref right, op.Pos);
left = Expression.OrElse(left, right);
}
return left;
}
// And operator
// - &&
// - And
// - AndAlso
private Expression ParseAndOperator()
{
Expression left = ParseIn();
while (_textParser.CurrentToken.Id == TokenId.DoubleAmpersand)
{
Token op = _textParser.CurrentToken;
_textParser.NextToken();
Expression right = ParseIn();
CheckAndPromoteOperands(typeof(ILogicalSignatures), op.Id, op.Text, ref left, ref right, op.Pos);
left = Expression.AndAlso(left, right);
}
return left;
}
// in operator for literals - example: "x in (1,2,3,4)"
// in operator to mimic contains - example: "x in @0", compare to @0.Contains(x)
// Adapted from ticket submitted by github user mlewis9548
private Expression ParseIn()
{
Expression left = ParseLogicalAndOrOperator();
Expression accumulate = left;
while (TokenIdentifierIs("in"))
{
var op = _textParser.CurrentToken;
_textParser.NextToken();
if (_textParser.CurrentToken.Id == TokenId.OpenParen) // literals (or other inline list)
{
while (_textParser.CurrentToken.Id != TokenId.CloseParen)
{
_textParser.NextToken();
// we need to parse unary expressions because otherwise 'in' clause will fail in use cases like 'in (-1, -1)' or 'in (!true)'
Expression right = ParseUnary();
// if the identifier is an Enum, try to convert the right-side also to an Enum.
if (left.Type.GetTypeInfo().IsEnum)
{
if (right is ConstantExpression constantExprRight)
{
right = ParseEnumToConstantExpression(op.Pos, left.Type, constantExprRight);
}
else if (_expressionHelper.TryUnwrapAsConstantExpression(right, out var unwrappedConstantExprRight))
{
right = ParseEnumToConstantExpression(op.Pos, left.Type, unwrappedConstantExprRight);
}
}
// else, check for direct type match
else if (left.Type != right.Type)
{
CheckAndPromoteOperands(typeof(IEqualitySignatures), TokenId.DoubleEqual, "==", ref left, ref right, op.Pos);
}
if (accumulate.Type != typeof(bool))
{
accumulate = _expressionHelper.GenerateEqual(left, right);
}
else
{
accumulate = Expression.OrElse(accumulate, _expressionHelper.GenerateEqual(left, right));
}
if (_textParser.CurrentToken.Id == TokenId.End)
{
throw ParseError(op.Pos, Res.CloseParenOrCommaExpected);
}
}
// Since this started with an open paren, make sure to move off the close
_textParser.NextToken();
}
else if (_textParser.CurrentToken.Id == TokenId.Identifier) // a single argument
{
Expression right = ParsePrimary();
if (!typeof(IEnumerable).IsAssignableFrom(right.Type))
{
throw ParseError(_textParser.CurrentToken.Pos, Res.IdentifierImplementingInterfaceExpected, typeof(IEnumerable));
}
var typeArgs = new[] { left.Type };
var args = new[] { right, left };
accumulate = Expression.Call(typeof(Enumerable), nameof(Enumerable.Contains), typeArgs, args);
}
else
{
throw ParseError(op.Pos, Res.OpenParenOrIdentifierExpected);
}
}
return accumulate;
}
// &, | bitwise operators
private Expression ParseLogicalAndOrOperator()
{
Expression left = ParseComparisonOperator();
var leftType = left.Type;
var typesAreSame = true;
var numberOfArguments = 0;
while (_textParser.CurrentToken.Id is TokenId.Ampersand or TokenId.Bar)
{
Token op = _textParser.CurrentToken;
_textParser.NextToken();
Expression right = ParseComparisonOperator();
if (left.Type.GetTypeInfo().IsEnum)
{
left = Expression.Convert(left, Enum.GetUnderlyingType(left.Type));
}
if (right.Type.GetTypeInfo().IsEnum)
{
right = Expression.Convert(right, Enum.GetUnderlyingType(right.Type));
}
switch (op.Id)
{
case TokenId.Ampersand:
if (left.Type == typeof(string) && left.NodeType == ExpressionType.Constant && int.TryParse((string?)((ConstantExpression)left).Value, out var parseValue) && TypeHelper.IsNumericType(right.Type))
{
left = Expression.Constant(parseValue);
}
else if (right.Type == typeof(string) && right.NodeType == ExpressionType.Constant && int.TryParse((string?)((ConstantExpression)right).Value, out parseValue) && TypeHelper.IsNumericType(left.Type))
{
right = Expression.Constant(parseValue);
}
// When at least one side of the operator is a string, consider it's a VB-style concatenation operator.
// Doesn't break any other function since logical AND with a string is invalid anyway.
if (left.Type == typeof(string) || right.Type == typeof(string))
{
left = _expressionHelper.GenerateStringConcat(left, right);
}
else
{
typesAreSame &= _expressionHelper.ConvertNumericTypeToBiggestCommonTypeForBinaryOperator(ref left, ref right);
left = Expression.And(left, right);
}
break;
case TokenId.Bar:
typesAreSame &= _expressionHelper.ConvertNumericTypeToBiggestCommonTypeForBinaryOperator(ref left, ref right);
left = Expression.Or(left, right);
break;
}
numberOfArguments++;
}
// #695
if (numberOfArguments > 0 && typesAreSame && leftType.GetTypeInfo().IsEnum)
{
return Expression.Convert(left, leftType);
}
return left;
}
// =, ==, !=, <>, >, >=, <, <= operators
private Expression ParseComparisonOperator()
{
Expression left = ParseShiftOperator();
while (_textParser.CurrentToken.Id == TokenId.Equal || _textParser.CurrentToken.Id == TokenId.DoubleEqual ||
_textParser.CurrentToken.Id == TokenId.ExclamationEqual || _textParser.CurrentToken.Id == TokenId.LessGreater ||
_textParser.CurrentToken.Id == TokenId.GreaterThan || _textParser.CurrentToken.Id == TokenId.GreaterThanEqual ||
_textParser.CurrentToken.Id == TokenId.LessThan || _textParser.CurrentToken.Id == TokenId.LessThanEqual)
{
ConstantExpression? constantExpr;
TypeConverter typeConverter;
Token op = _textParser.CurrentToken;
_textParser.NextToken();
Expression right = ParseShiftOperator();
bool isEquality = op.Id == TokenId.Equal || op.Id == TokenId.DoubleEqual || op.Id == TokenId.ExclamationEqual || op.Id == TokenId.LessGreater;
if (isEquality && (!left.Type.GetTypeInfo().IsValueType && !right.Type.GetTypeInfo().IsValueType || left.Type == typeof(Guid) && right.Type == typeof(Guid)))
{
// If left or right is NullLiteral, just continue. Else check if the types differ.
if (!(Constants.IsNull(left) || Constants.IsNull(right)) && left.Type != right.Type)
{
if (left.Type.IsAssignableFrom(right.Type) || HasImplicitConversion(right.Type, left.Type))
{
right = Expression.Convert(right, left.Type);
}
else if (right.Type.IsAssignableFrom(left.Type) || HasImplicitConversion(left.Type, right.Type))
{
left = Expression.Convert(left, right.Type);
}
else
{
throw IncompatibleOperandsError(op.Text, left, right, op.Pos);
}
}
}
else if (TypeHelper.IsEnumType(left.Type) || TypeHelper.IsEnumType(right.Type))
{
if (left.Type != right.Type)
{
Expression? e;
if ((e = _parsingConfig.ExpressionPromoter.Promote(right, left.Type, true, false)) != null)
{
right = e;
}
else if ((e = _parsingConfig.ExpressionPromoter.Promote(left, right.Type, true, false)) != null)
{
left = e;
}
else if (TypeHelper.IsEnumType(left.Type))
{
if (right is ConstantExpression constantExprRight)
{
right = ParseEnumToConstantExpression(op.Pos, left.Type, constantExprRight);
}
else if (_expressionHelper.TryUnwrapAsConstantExpression(right, out var unwrappedConstantExprRight))
{
right = ParseEnumToConstantExpression(op.Pos, left.Type, unwrappedConstantExprRight);
}
}
else if (TypeHelper.IsEnumType(right.Type))
{
if (left is ConstantExpression constantExprLeft)
{
left = ParseEnumToConstantExpression(op.Pos, right.Type, constantExprLeft);
}
else if (_expressionHelper.TryUnwrapAsConstantExpression(left, out var unwrappedConstantExprLeft))
{
left = ParseEnumToConstantExpression(op.Pos, right.Type, unwrappedConstantExprLeft);
}
}
else
{
throw IncompatibleOperandsError(op.Text, left, right, op.Pos);
}
}
}
else if ((constantExpr = right as ConstantExpression) != null && constantExpr.Value is string stringValueR && (typeConverter = _typeConverterFactory.GetConverter(left.Type)) != null && typeConverter.CanConvertFrom(right.Type))
{
right = Expression.Constant(typeConverter.ConvertFromInvariantString(stringValueR), left.Type);
}
else if ((constantExpr = left as ConstantExpression) != null && constantExpr.Value is string stringValueL && (typeConverter = _typeConverterFactory.GetConverter(right.Type)) != null && typeConverter.CanConvertFrom(left.Type))
{
left = Expression.Constant(typeConverter.ConvertFromInvariantString(stringValueL), right.Type);
}
else if (_expressionHelper.TryUnwrapAsValue<string>(right, out var unwrappedStringValueR) && (typeConverter = _typeConverterFactory.GetConverter(left.Type)) != null && typeConverter.CanConvertFrom(right.Type))
{
right = Expression.Constant(typeConverter.ConvertFromInvariantString(unwrappedStringValueR), left.Type);
}
else if (_expressionHelper.TryUnwrapAsValue<string>(left, out var unwrappedStringValueL) && (typeConverter = _typeConverterFactory.GetConverter(right.Type)) != null && typeConverter.CanConvertFrom(left.Type))
{
left = Expression.Constant(typeConverter.ConvertFromInvariantString(unwrappedStringValueL), right.Type);
}
else
{
bool typesAreSameAndImplementCorrectInterface = false;
if (left.Type == right.Type)
{
var interfaces = left.Type.GetInterfaces().Where(x => x.GetTypeInfo().IsGenericType);
if (isEquality)
{
typesAreSameAndImplementCorrectInterface = interfaces.Any(x => x.GetGenericTypeDefinition() == typeof(IEquatable<>));
}
else
{
typesAreSameAndImplementCorrectInterface = interfaces.Any(x => x.GetGenericTypeDefinition() == typeof(IComparable<>));
}
}
if (!typesAreSameAndImplementCorrectInterface)
{
if ((TypeHelper.IsClass(left.Type) || TypeHelper.IsStruct(left.Type)) && right is ConstantExpression)
{
if (HasImplicitConversion(left.Type, right.Type))
{
left = Expression.Convert(left, right.Type);
}
else if (HasImplicitConversion(right.Type, left.Type))
{
right = Expression.Convert(right, left.Type);
}
}
else if ((TypeHelper.IsClass(right.Type) || TypeHelper.IsStruct(right.Type)) && left is ConstantExpression)
{
if (HasImplicitConversion(right.Type, left.Type))
{
right = Expression.Convert(right, left.Type);
}
else if (HasImplicitConversion(left.Type, right.Type))
{
left = Expression.Convert(left, right.Type);
}
}
else
{
CheckAndPromoteOperands(isEquality ? typeof(IEqualitySignatures) : typeof(IRelationalSignatures), op.Id, op.Text, ref left, ref right, op.Pos);
}
}
}
switch (op.Id)
{
case TokenId.Equal:
case TokenId.DoubleEqual:
left = _expressionHelper.GenerateEqual(left, right);
break;
case TokenId.ExclamationEqual:
case TokenId.LessGreater:
left = _expressionHelper.GenerateNotEqual(left, right);
break;
case TokenId.GreaterThan:
left = _expressionHelper.GenerateGreaterThan(left, right);
break;
case TokenId.GreaterThanEqual:
left = _expressionHelper.GenerateGreaterThanEqual(left, right);
break;
case TokenId.LessThan:
left = _expressionHelper.GenerateLessThan(left, right);
break;
case TokenId.LessThanEqual:
left = _expressionHelper.GenerateLessThanEqual(left, right);
break;
}
}
return left;
}
private static bool HasImplicitConversion(Type baseType, Type targetType)
{
var baseTypeHasConversion = baseType.GetMethods(BindingFlags.Public | BindingFlags.Static)
.Where(mi => mi.Name == "op_Implicit" && mi.ReturnType == targetType)
.Any(mi => mi.GetParameters().FirstOrDefault()?.ParameterType == baseType);
if (baseTypeHasConversion)
{
return true;
}
return targetType.GetMethods(BindingFlags.Public | BindingFlags.Static)
.Where(mi => mi.Name == "op_Implicit" && mi.ReturnType == targetType)
.Any(mi => mi.GetParameters().FirstOrDefault()?.ParameterType == baseType);
}
private static ConstantExpression ParseEnumToConstantExpression(int pos, Type leftType, ConstantExpression constantExpr)
{
return Expression.Constant(ParseConstantExpressionToEnum(pos, leftType, constantExpr), leftType);
}
private static object ParseConstantExpressionToEnum(int pos, Type leftType, ConstantExpression constantExpr)
{
try
{
if (constantExpr.Value is string stringValue)
{
return Enum.Parse(TypeHelper.GetNonNullableType(leftType), stringValue, true);
}
}
catch
{
throw ParseError(pos, Res.ExpressionTypeMismatch, leftType);
}
try
{
return Enum.ToObject(TypeHelper.GetNonNullableType(leftType), constantExpr.Value!);
}
catch
{
throw ParseError(pos, Res.ExpressionTypeMismatch, leftType);
}
}
// <<, >> operators
private Expression ParseShiftOperator()
{
Expression left = ParseAdditive();
while (_textParser.CurrentToken.Id == TokenId.DoubleLessThan || _textParser.CurrentToken.Id == TokenId.DoubleGreaterThan)
{
Token op = _textParser.CurrentToken;
_textParser.NextToken();
Expression right = ParseAdditive();
switch (op.Id)
{
case TokenId.DoubleLessThan:
CheckAndPromoteOperands(typeof(IShiftSignatures), op.Id, op.Text, ref left, ref right, op.Pos);
left = Expression.LeftShift(left, right);
break;
case TokenId.DoubleGreaterThan:
CheckAndPromoteOperands(typeof(IShiftSignatures), op.Id, op.Text, ref left, ref right, op.Pos);
left = Expression.RightShift(left, right);
break;
}
}
return left;
}
// +, - operators
private Expression ParseAdditive()
{
Expression left = ParseArithmetic();
while (_textParser.CurrentToken.Id is TokenId.Plus or TokenId.Minus)
{
Token op = _textParser.CurrentToken;
_textParser.NextToken();
Expression right = ParseArithmetic();
switch (op.Id)
{
case TokenId.Plus:
if (left.Type == typeof(string) || right.Type == typeof(string))
{
left = _expressionHelper.GenerateStringConcat(left, right);
}
else
{
CheckAndPromoteOperands(typeof(IAddSignatures), op.Id, op.Text, ref left, ref right, op.Pos);
left = _expressionHelper.GenerateAdd(left, right);
}
break;
case TokenId.Minus:
CheckAndPromoteOperands(typeof(ISubtractSignatures), op.Id, op.Text, ref left, ref right, op.Pos);
left = _expressionHelper.GenerateSubtract(left, right);
break;
}
}
return left;
}
// *, /, %, mod operators
private Expression ParseArithmetic()
{
Expression left = ParseUnary();
while (_textParser.CurrentToken.Id is TokenId.Asterisk or TokenId.Slash or TokenId.Percent || TokenIdentifierIs("mod"))
{
Token op = _textParser.CurrentToken;
_textParser.NextToken();
Expression right = ParseUnary();
CheckAndPromoteOperands(typeof(IArithmeticSignatures), op.Id, 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
private Expression ParseUnary()
{
if (_textParser.CurrentToken.Id == TokenId.Minus || _textParser.CurrentToken.Id == TokenId.Exclamation || TokenIdentifierIs("not"))
{
Token op = _textParser.CurrentToken;
_textParser.NextToken();
if (op.Id == TokenId.Minus && (_textParser.CurrentToken.Id == TokenId.IntegerLiteral || _textParser.CurrentToken.Id == TokenId.RealLiteral))
{
_textParser.CurrentToken.Text = "-" + _textParser.CurrentToken.Text;
_textParser.CurrentToken.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();
}
private Expression ParsePrimary()
{
var expr = ParsePrimaryStart();
_expressionHelper.WrapConstantExpression(ref expr);
while (true)
{
if (_textParser.CurrentToken.Id == TokenId.Dot)
{
_textParser.NextToken();
expr = ParseMemberAccess(null, expr);
}
else if (_textParser.CurrentToken.Id == TokenId.NullPropagation)
{
throw new NotSupportedException("An expression tree lambda may not contain a null propagating operator. Use the 'np()' or 'np(...)' (null-propagation) function instead.");
}
else if (_textParser.CurrentToken.Id == TokenId.OpenBracket)
{
expr = ParseElementAccess(expr);
}
else
{
break;
}
}
return expr;
}
private Expression ParsePrimaryStart()
{
switch (_textParser.CurrentToken.Id)
{
case TokenId.Identifier:
return ParseIdentifier();
case TokenId.StringLiteral:
return ParseStringLiteralAsStringExpressionOrTypeExpression();
case TokenId.IntegerLiteral:
return ParseIntegerLiteral();
case TokenId.RealLiteral:
return ParseRealLiteral();
case TokenId.OpenParen:
return ParseParenExpression();
default:
throw ParseError(Res.ExpressionExpected);
}
}
private Expression ParseStringLiteralAsStringExpressionOrTypeExpression()
{
var clonedTextParser = _textParser.Clone();
clonedTextParser.NextToken();
// Check if next token is a "(" or a "?(".
// Used for casting like $"\"System.DateTime\"(Abc)" or $"\"System.DateTime\"?(Abc)".
// In that case, the string value is NOT forced to stay a string.
bool forceParseAsString = true;
if (clonedTextParser.CurrentToken.Id == TokenId.OpenParen)
{
forceParseAsString = false;
}
else if (clonedTextParser.CurrentToken.Id == TokenId.Question)
{
clonedTextParser.NextToken();
if (clonedTextParser.CurrentToken.Id == TokenId.OpenParen)
{
forceParseAsString = false;
}
}
var expressionOrType = ParseStringLiteral(forceParseAsString);
return expressionOrType.IsFirst ? expressionOrType.First : ParseTypeAccess(expressionOrType.Second, false);
}
private AnyOf<Expression, Type> ParseStringLiteral(bool forceParseAsString)
{
_textParser.ValidateToken(TokenId.StringLiteral);
var text = _textParser.CurrentToken.Text;
var parsedStringValue = StringParser.ParseString(_textParser.CurrentToken.Text);
if (_textParser.CurrentToken.Text[0] == '\'')
{
if (parsedStringValue.Length > 1)
{
throw ParseError(Res.InvalidCharacterLiteral);
}
_textParser.NextToken();
return _constantExpressionHelper.CreateLiteral(parsedStringValue[0], parsedStringValue);
}
_textParser.NextToken();
if (_parsingConfig.SupportCastingToFullyQualifiedTypeAsString && !forceParseAsString && parsedStringValue.Length > 2 && parsedStringValue.Contains('.'))
{
// Try to resolve this string as a type
var type = _typeFinder.FindTypeByName(parsedStringValue, null, false);
if (type is { })
{
return type;
}
}
// While the next token is also a string, keep concatenating these strings and get next token
while (_textParser.CurrentToken.Id == TokenId.StringLiteral)
{
text += _textParser.CurrentToken.Text;
_textParser.NextToken();
}
parsedStringValue = StringParser.ParseStringAndReplaceDoubleQuotes(text, _textParser.CurrentToken.Pos);
return _constantExpressionHelper.CreateLiteral(parsedStringValue, parsedStringValue);
}
private Expression ParseIntegerLiteral()
{
_textParser.ValidateToken(TokenId.IntegerLiteral);
string text = _textParser.CurrentToken.Text;
var tokenPosition = _textParser.CurrentToken.Pos;
var constantExpression = _numberParser.ParseIntegerLiteral(tokenPosition, text);
_textParser.NextToken();
return constantExpression;
}
private Expression ParseRealLiteral()
{
_textParser.ValidateToken(TokenId.RealLiteral);
string text = _textParser.CurrentToken.Text;
_textParser.NextToken();
return _numberParser.ParseRealLiteral(text, text[text.Length - 1], true);
}
private Expression ParseParenExpression()
{
_textParser.ValidateToken(TokenId.OpenParen, Res.OpenParenExpected);
_textParser.NextToken();
Expression e = ParseConditionalOperator();
_textParser.ValidateToken(TokenId.CloseParen, Res.CloseParenOrOperatorExpected);
_textParser.NextToken();
return e;
}
private Expression ParseIdentifier()
{
_textParser.ValidateToken(TokenId.Identifier);
var isValidKeyWord = _keywordsHelper.TryGetValue(_textParser.CurrentToken.Text, out var value);
bool shouldPrioritizeType = true;
if (_parsingConfig.PrioritizePropertyOrFieldOverTheType && value is Type)
{
bool isPropertyOrField = _it != null && FindPropertyOrField(_it.Type, _textParser.CurrentToken.Text, false) != null;
bool hasSymbol = _symbols.ContainsKey(_textParser.CurrentToken.Text);
if (isPropertyOrField || hasSymbol)
{
shouldPrioritizeType = false;
}
}
if (isValidKeyWord && shouldPrioritizeType)
{
if (value is Type typeValue)
{
return ParseTypeAccess(typeValue, true);
}
switch (value)
{
case KeywordsHelper.KEYWORD_IT:
case KeywordsHelper.SYMBOL_IT:
return ParseIt();
case KeywordsHelper.KEYWORD_PARENT:
case KeywordsHelper.SYMBOL_PARENT:
return ParseParent();
case KeywordsHelper.KEYWORD_ROOT:
case KeywordsHelper.SYMBOL_ROOT:
return ParseRoot();
case KeywordsHelper.FUNCTION_IIF:
return ParseFunctionIif();
case KeywordsHelper.FUNCTION_ISNULL: