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1.1.3
by Sebastian Dröge
Import upstream version 0.11+svn20060818 |
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// <file>
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// <copyright see="prj:///doc/copyright.txt"/>
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// <license see="prj:///doc/license.txt"/>
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// <owner name="Mike Krüger" email="mike@icsharpcode.net"/>
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// <version>$Revision: 975 $</version>
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// </file>
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using System; |
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using System.Collections; |
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namespace ICSharpCode.NRefactory.Parser.AST |
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{
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public abstract class Expression : AbstractNode, INullable |
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{
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public static NullExpression Null { |
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get { |
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return NullExpression.Instance; |
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}
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}
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public virtual bool IsNull { |
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get { |
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return false; |
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}
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}
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public static Expression CheckNull(Expression expression) |
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{
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return expression == null ? NullExpression.Instance : expression; |
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}
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/// <summary>
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/// Returns the existing expression plus the specified integer value.
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/// WARNING: This method modifies <paramref name="expr"/> and possibly returns <paramref name="expr"/>
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/// again, but it might also create a new expression around <paramref name="expr"/>.
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/// </summary>
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public static Expression AddInteger(Expression expr, int value) |
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{
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PrimitiveExpression pe = expr as PrimitiveExpression; |
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if (pe != null && pe.Value is int) { |
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int newVal = (int)pe.Value + value; |
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return new PrimitiveExpression(newVal, newVal.ToString(System.Globalization.NumberFormatInfo.InvariantInfo)); |
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}
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BinaryOperatorExpression boe = expr as BinaryOperatorExpression; |
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if (boe != null && boe.Op == BinaryOperatorType.Add) { |
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boe.Right = AddInteger(boe.Right, value); |
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if (boe.Right is PrimitiveExpression && ((PrimitiveExpression)boe.Right).Value is int) { |
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int newVal = (int)((PrimitiveExpression)boe.Right).Value; |
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if (newVal == 0) { |
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return boe.Left; |
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} else if (newVal < 0) { |
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((PrimitiveExpression)boe.Right).Value = -newVal; |
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boe.Op = BinaryOperatorType.Subtract; |
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}
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}
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return boe; |
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}
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if (boe != null && boe.Op == BinaryOperatorType.Subtract) { |
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pe = boe.Right as PrimitiveExpression; |
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if (pe != null && pe.Value is int) { |
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int newVal = (int)pe.Value - value; |
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if (newVal == 0) |
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return boe.Left; |
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if (newVal < 0) { |
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newVal = -newVal; |
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boe.Op = BinaryOperatorType.Add; |
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}
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boe.Right = new PrimitiveExpression(newVal, newVal.ToString(System.Globalization.NumberFormatInfo.InvariantInfo)); |
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return boe; |
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}
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}
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BinaryOperatorType opType = BinaryOperatorType.Add; |
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if (value < 0) { |
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value = -value; |
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opType = BinaryOperatorType.Subtract; |
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}
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return new BinaryOperatorExpression(expr, opType, new PrimitiveExpression(value, value.ToString(System.Globalization.NumberFormatInfo.InvariantInfo))); |
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}
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}
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public class NullExpression : Expression |
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{
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static NullExpression nullExpression = new NullExpression(); |
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public override bool IsNull { |
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get { |
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return true; |
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}
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}
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public static NullExpression Instance { |
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get { |
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return nullExpression; |
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}
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}
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NullExpression() |
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{
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}
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public override object AcceptVisitor(IAstVisitor visitor, object data) |
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{
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return null; |
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}
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public override string ToString() |
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{
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return String.Format("[NullExpression]"); |
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}
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}
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}
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