// The Nova Project by Ken Beckett.
// Copyright (C) 2007-2012 Inevitable Software, all rights reserved.
// Released under the Common Development and Distribution License, CDDL-1.0: http://opensource.org/licenses/cddl1.php
using System;
using Nova.Parsing;
namespace Nova.CodeDOM
{
/// <summary>
/// Adds one <see cref="Expression"/> to another.
/// </summary>
public class Add : BinaryArithmeticOperator
{
#region /* CONSTANTS */
/// <summary>
/// The internal name of the operator.
/// </summary>
public const string InternalName = NamePrefix + "Addition";
#endregion
#region /* CONSTRUCTORS */
/// <summary>
/// Create an <see cref="Add"/> operator.
/// </summary>
public Add(Expression left, Expression right)
: base(left, right)
{ }
#endregion
#region /* PROPERTIES */
/// <summary>
/// The symbol associated with the operator.
/// </summary>
public override string Symbol
{
get { return ParseToken; }
}
#endregion
#region /* METHODS */
/// <summary>
/// The internal name of the <see cref="BinaryOperator"/>.
/// </summary>
public override string GetInternalName()
{
return InternalName;
}
#endregion
#region /* PARSING */
/// <summary>
/// The token used to parse the code object.
/// </summary>
public const string ParseToken = "+";
/// <summary>
/// The precedence of the operator.
/// </summary>
public const int Precedence = 310;
/// <summary>
/// True if the operator is left-associative, or false if it's right-associative.
/// </summary>
public const bool LeftAssociative = true;
internal static new void AddParsePoints()
{
Parser.AddOperatorParsePoint(ParseToken, Precedence, LeftAssociative, false, Parse);
}
/// <summary>
/// Parse an <see cref="Add"/> operator.
/// </summary>
public static Add Parse(Parser parser, CodeObject parent, ParseFlags flags)
{
// Verify that we have a left expression before proceeding, otherwise abort
// (this is to give the Positive operator a chance at parsing it)
if (parser.HasUnusedExpression)
return new Add(parser, parent);
return null;
}
protected Add(Parser parser, CodeObject parent)
: base(parser, parent)
{ }
/// <summary>
/// Get the precedence of the operator.
/// </summary>
public override int GetPrecedence()
{
return Precedence;
}
#endregion
#region /* RESOLVING */
/// <summary>
/// Evaluate the type of the <see cref="Expression"/>.
/// </summary>
/// <returns>The resulting <see cref="TypeRef"/> or <see cref="UnresolvedRef"/>.</returns>
public override TypeRefBase EvaluateType(bool withoutConstants)
{
// If we have a reference to an overloaded operator declaration, use its return type
if (_operatorRef is OperatorRef)
return ((OperatorRef)_operatorRef).GetReturnType();
// Determine the types of both sides
TypeRefBase leftTypeRefBase = (_left != null ? _left.EvaluateType(withoutConstants) : null);
TypeRefBase rightTypeRefBase = (_right != null ? _right.EvaluateType(withoutConstants) : null);
if (leftTypeRefBase is TypeRef && rightTypeRefBase is TypeRef)
{
TypeRef leftTypeRef = (TypeRef)leftTypeRefBase;
TypeRef rightTypeRef = (TypeRef)rightTypeRefBase;
// Handle constants
if (!withoutConstants && leftTypeRef.IsConst && rightTypeRef.IsConst)
{
object result = EvaluateConstants(leftTypeRef.GetConstantValue(), rightTypeRef.GetConstantValue());
return (result != null ? new TypeRef(result) : TypeRef.ObjectRef);
}
// Evaluate as a string if either side is a string OR the left side is implicitly convertible to a string (string concatenation)
if (leftTypeRef.IsSameRef(TypeRef.StringRef) || rightTypeRef.IsSameRef(TypeRef.StringRef)
|| leftTypeRef.UserDefinedImplicitConversionExists(TypeRef.StringRef))
return TypeRef.StringRef;
// Boolean operands aren't supported
if (leftTypeRef.IsSameRef(TypeRef.BoolRef) || rightTypeRef.IsSameRef(TypeRef.BoolRef))
return null;
// Enumeration addition: If one side is an enum and the other is of the underlying type
// of the enum (or is implicitly convertible to it), then the result is the enum type.
// E +(E, U):
if (leftTypeRef.IsEnum)
return (rightTypeRef.IsImplicitlyConvertibleTo(leftTypeRef.GetUnderlyingTypeOfEnum()) ? leftTypeRef : TypeRef.ObjectRef);
// E +(U, E):
if (rightTypeRef.IsEnum)
return (leftTypeRef.IsImplicitlyConvertibleTo(rightTypeRef.GetUnderlyingTypeOfEnum()) ? rightTypeRef : TypeRef.ObjectRef);
}
else if (leftTypeRefBase != null && rightTypeRefBase != null)
{
// Evaluate as a string if one side is unresolved and the other is a string (reduce error propagation)
if (leftTypeRefBase.IsSameRef(TypeRef.StringRef) || rightTypeRefBase.IsSameRef(TypeRef.StringRef))
return TypeRef.StringRef;
}
// By default, determine a common type (using implicit conversions) that can handle the
// result of the operation.
return TypeRef.GetCommonType(leftTypeRefBase, rightTypeRefBase);
}
/// <summary>
/// Add two constant objects.
/// Supported types are: string, bool, enum, decimal, double, float, ulong, long, uint, int, ushort, short, char, byte, sbyte.
/// </summary>
/// <returns>
/// The sum of the two constants, using the appropriate result type, including promoting smaller
/// types to int. Returns null if the operation is invalid.
/// </returns>
protected override object EvaluateConstants(object leftConstant, object rightConstant)
{
// Do string concatenation if either side is a string (even if the other side is null)
if (leftConstant is string)
return ((string)leftConstant + rightConstant);
if (rightConstant is string)
return (leftConstant + (string)rightConstant);
// Check for null constants
if (leftConstant == null || rightConstant == null)
return null; // The operation is invalid
// Boolean operands aren't supported
if (leftConstant is bool || rightConstant is bool)
return null; // The operation is invalid
// Handle enum constants
// Enumeration addition: If one side is an enum and the other is of the underlying type
// of the enum (or is implicitly convertible to it), then the result is the enum type.
if (leftConstant is EnumConstant)
{
if (!(rightConstant is EnumConstant))
{
EnumConstant leftEnumConstant = (EnumConstant)leftConstant;
TypeRefBase underlyingTypeRefBase = leftEnumConstant.EnumTypeRef.GetUnderlyingTypeOfEnum();
TypeRef rightTypeRef = new TypeRef(rightConstant.GetType());
if (rightTypeRef.IsImplicitlyConvertibleTo(underlyingTypeRefBase))
{
// E +(E, U):
object enumValue = EvaluateConstants(leftEnumConstant.ConstantValue, rightConstant);
if (enumValue != null)
return new EnumConstant(leftEnumConstant.EnumTypeRef, TypeRef.ChangeTypeOfConstant(enumValue, underlyingTypeRefBase));
}
}
return null; // The operation is invalid
}
if (rightConstant is EnumConstant)
{
EnumConstant rightEnumConstant = (EnumConstant)rightConstant;
TypeRefBase underlyingTypeRefBase = rightEnumConstant.EnumTypeRef.GetUnderlyingTypeOfEnum();
TypeRef leftTypeRef = new TypeRef(leftConstant.GetType());
if (leftTypeRef.IsImplicitlyConvertibleTo(underlyingTypeRefBase))
{
// E +(U, E):
object enumValue = EvaluateConstants(leftConstant, rightEnumConstant.ConstantValue);
if (enumValue != null)
return new EnumConstant(rightEnumConstant.EnumTypeRef, TypeRef.ChangeTypeOfConstant(enumValue, underlyingTypeRefBase));
}
return null; // The operation is invalid
}
// Do binary numeric promotions
if (leftConstant is decimal)
{
if (rightConstant is float || rightConstant is double)
return null; // The operation is invalid
return (decimal)leftConstant + Convert.ToDecimal(rightConstant);
}
if (rightConstant is decimal)
{
if (leftConstant is float || leftConstant is double)
return null; // The operation is invalid
return Convert.ToDecimal(leftConstant) + (decimal)rightConstant;
}
if (leftConstant is double)
return (double)leftConstant + Convert.ToDouble(rightConstant);
if (rightConstant is double)
return Convert.ToDouble(leftConstant) + (double)rightConstant;
if (leftConstant is float)
return (float)leftConstant + Convert.ToSingle(rightConstant);
if (rightConstant is float)
return Convert.ToSingle(leftConstant) + (float)rightConstant;
if (leftConstant is ulong)
{
if ((rightConstant is sbyte && (sbyte)rightConstant < 0) || (rightConstant is short && (short)rightConstant < 0)
|| (rightConstant is int && (int)rightConstant < 0) || (rightConstant is long && (long)rightConstant < 0))
return null; // The operation is invalid
return (ulong)leftConstant + Convert.ToUInt64(rightConstant);
}
if (rightConstant is ulong)
{
if ((leftConstant is sbyte && (sbyte)leftConstant < 0) || (leftConstant is short && (short)leftConstant < 0)
|| (leftConstant is int && (int)leftConstant < 0) || (leftConstant is long && (long)leftConstant < 0))
return null; // The operation is invalid
return Convert.ToUInt64(leftConstant) + (ulong)rightConstant;
}
if (leftConstant is long)
return (long)leftConstant + Convert.ToInt64(rightConstant);
if (rightConstant is long)
return Convert.ToInt64(leftConstant) + (long)rightConstant;
if (leftConstant is uint)
{
if ((rightConstant is sbyte && (sbyte)rightConstant < 0) || (rightConstant is short && (short)rightConstant < 0)
|| (rightConstant is int && (int)rightConstant < 0))
return Convert.ToInt64(leftConstant) + Convert.ToInt64(rightConstant);
return (uint)leftConstant + Convert.ToUInt32(rightConstant);
}
if (rightConstant is uint)
{
if ((leftConstant is sbyte && (sbyte)leftConstant < 0) || (leftConstant is short && (short)leftConstant < 0)
|| (leftConstant is int && (int)leftConstant < 0))
return Convert.ToInt64(leftConstant) + Convert.ToInt64(rightConstant);
return Convert.ToUInt32(leftConstant) + (uint)rightConstant;
}
// All other cases (with smaller integral types) get promoted to ints
return Convert.ToInt32(leftConstant) + Convert.ToInt32(rightConstant);
}
#endregion
}
}
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