class/System.Core/System.Linq.Expressions/ExpressionVisitor.cs

   1 //
   2 // ExpressionVisitor.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@novell.com)
   6 //
   7 // (C) 2008 Novell, Inc. (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.Collections.ObjectModel;
  31
  32 namespace System.Linq.Expressions {
  33
  34         abstract class ExpressionVisitor {
  35
  36                 protected virtual void Visit (Expression expression)
  37                 {
  38                         if (expression == null)
  39                                 return;
  40
  41                         switch (expression.NodeType) {
  42                         case ExpressionType.Negate:
  43                         case ExpressionType.NegateChecked:
  44                         case ExpressionType.Not:
  45                         case ExpressionType.Convert:
  46                         case ExpressionType.ConvertChecked:
  47                         case ExpressionType.ArrayLength:
  48                         case ExpressionType.Quote:
  49                         case ExpressionType.TypeAs:
  50                         case ExpressionType.UnaryPlus:
  51                                 VisitUnary ((UnaryExpression) expression);
  52                                 break;
  53                         case ExpressionType.Add:
  54                         case ExpressionType.AddChecked:
  55                         case ExpressionType.Subtract:
  56                         case ExpressionType.SubtractChecked:
  57                         case ExpressionType.Multiply:
  58                         case ExpressionType.MultiplyChecked:
  59                         case ExpressionType.Divide:
  60                         case ExpressionType.Modulo:
  61                         case ExpressionType.Power:
  62                         case ExpressionType.And:
  63                         case ExpressionType.AndAlso:
  64                         case ExpressionType.Or:
  65                         case ExpressionType.OrElse:
  66                         case ExpressionType.LessThan:
  67                         case ExpressionType.LessThanOrEqual:
  68                         case ExpressionType.GreaterThan:
  69                         case ExpressionType.GreaterThanOrEqual:
  70                         case ExpressionType.Equal:
  71                         case ExpressionType.NotEqual:
  72                         case ExpressionType.Coalesce:
  73                         case ExpressionType.ArrayIndex:
  74                         case ExpressionType.RightShift:
  75                         case ExpressionType.LeftShift:
  76                         case ExpressionType.ExclusiveOr:
  77                                 VisitBinary ((BinaryExpression) expression);
  78                                 break;
  79                         case ExpressionType.TypeIs:
  80                                 VisitTypeIs ((TypeBinaryExpression) expression);
  81                                 break;
  82                         case ExpressionType.Conditional:
  83                                 VisitConditional ((ConditionalExpression) expression);
  84                                 break;
  85                         case ExpressionType.Constant:
  86                                 VisitConstant ((ConstantExpression) expression);
  87                                 break;
  88                         case ExpressionType.Parameter:
  89                                 VisitParameter ((ParameterExpression) expression);
  90                                 break;
  91                         case ExpressionType.MemberAccess:
  92                                 VisitMemberAccess ((MemberExpression) expression);
  93                                 break;
  94                         case ExpressionType.Call:
  95                                 VisitMethodCall ((MethodCallExpression) expression);
  96                                 break;
  97                         case ExpressionType.Lambda:
  98                                 VisitLambda ((LambdaExpression) expression);
  99                                 break;
 100                         case ExpressionType.New:
 101                                 VisitNew ((NewExpression) expression);
 102                                 break;
 103                         case ExpressionType.NewArrayInit:
 104                         case ExpressionType.NewArrayBounds:
 105                                 VisitNewArray ((NewArrayExpression) expression);
 106                                 break;
 107                         case ExpressionType.Invoke:
 108                                 VisitInvocation ((InvocationExpression) expression);
 109                                 break;
 110                         case ExpressionType.MemberInit:
 111                                 VisitMemberInit ((MemberInitExpression) expression);
 112                                 break;
 113                         case ExpressionType.ListInit:
 114                                 VisitListInit ((ListInitExpression) expression);
 115                                 break;
 116                         default:
 117                                 throw new ArgumentException (string.Format ("Unhandled expression type: '{0}'", expression.NodeType));
 118                         }
 119                 }
 120
 121                 protected virtual void VisitBinding (MemberBinding binding)
 122                 {
 123                         switch (binding.BindingType) {
 124                         case MemberBindingType.Assignment:
 125                                 VisitMemberAssignment ((MemberAssignment) binding);
 126                                 break;
 127                         case MemberBindingType.MemberBinding:
 128                                 VisitMemberMemberBinding ((MemberMemberBinding) binding);
 129                                 break;
 130                         case MemberBindingType.ListBinding:
 131                                 VisitMemberListBinding ((MemberListBinding) binding);
 132                                 break;
 133                         default:
 134                                 throw new ArgumentException (string.Format ("Unhandled binding type '{0}'", binding.BindingType));
 135                         }
 136                 }
 137
 138                 protected virtual void VisitElementInitializer (ElementInit initializer)
 139                 {
 140                         VisitExpressionList (initializer.Arguments);
 141                 }
 142
 143                 protected virtual void VisitUnary (UnaryExpression unary)
 144                 {
 145                         Visit (unary.Operand);
 146                 }
 147
 148                 protected virtual void VisitBinary (BinaryExpression binary)
 149                 {
 150                         Visit (binary.Left);
 151                         Visit (binary.Right);
 152                         Visit (binary.Conversion);
 153                 }
 154
 155                 protected virtual void VisitTypeIs (TypeBinaryExpression type)
 156                 {
 157                         Visit (type.Expression);
 158                 }
 159
 160                 protected virtual void VisitConstant (ConstantExpression constant)
 161                 {
 162                 }
 163
 164                 protected virtual void VisitConditional (ConditionalExpression conditional)
 165                 {
 166                         Visit (conditional.Test);
 167                         Visit (conditional.IfTrue);
 168                         Visit (conditional.IfFalse);
 169                 }
 170
 171                 protected virtual void VisitParameter (ParameterExpression parameter)
 172                 {
 173                 }
 174
 175                 protected virtual void VisitMemberAccess (MemberExpression member)
 176                 {
 177                         Visit (member.Expression);
 178                 }
 179
 180                 protected virtual void VisitMethodCall (MethodCallExpression methodCall)
 181                 {
 182                         Visit (methodCall.Object);
 183                         VisitExpressionList (methodCall.Arguments);
 184                 }
 185
 186                 protected virtual void VisitList<T> (ReadOnlyCollection<T> list, Action<T> visitor)
 187                 {
 188                         foreach (T element in list) {
 189                                 visitor (element);
 190                         }
 191                 }
 192
 193                 protected virtual void VisitExpressionList (ReadOnlyCollection<Expression> list)
 194                 {
 195                         VisitList (list, Visit);
 196                 }
 197
 198                 protected virtual void VisitMemberAssignment (MemberAssignment assignment)
 199                 {
 200                         Visit (assignment.Expression);
 201                 }
 202
 203                 protected virtual void VisitMemberMemberBinding (MemberMemberBinding binding)
 204                 {
 205                         VisitBindingList (binding.Bindings);
 206                 }
 207
 208                 protected virtual void VisitMemberListBinding (MemberListBinding binding)
 209                 {
 210                         VisitElementInitializerList (binding.Initializers);
 211                 }
 212
 213                 protected virtual void VisitBindingList (ReadOnlyCollection<MemberBinding> list)
 214                 {
 215                         VisitList (list, VisitBinding);
 216                 }
 217
 218                 protected virtual void VisitElementInitializerList (ReadOnlyCollection<ElementInit> list)
 219                 {
 220                         VisitList (list, VisitElementInitializer);
 221                 }
 222
 223                 protected virtual void VisitLambda (LambdaExpression lambda)
 224                 {
 225                         Visit (lambda.Body);
 226                 }
 227
 228                 protected virtual void VisitNew (NewExpression nex)
 229                 {
 230                         VisitExpressionList (nex.Arguments);
 231                 }
 232
 233                 protected virtual void VisitMemberInit (MemberInitExpression init)
 234                 {
 235                         VisitNew (init.NewExpression);
 236                         VisitBindingList (init.Bindings);
 237                 }
 238
 239                 protected virtual void VisitListInit (ListInitExpression init)
 240                 {
 241                         VisitNew (init.NewExpression);
 242                         VisitElementInitializerList (init.Initializers);
 243                 }
 244
 245                 protected virtual void VisitNewArray (NewArrayExpression newArray)
 246                 {
 247                         VisitExpressionList (newArray.Expressions);
 248                 }
 249
 250                 protected virtual void VisitInvocation (InvocationExpression invocation)
 251                 {
 252                         VisitExpressionList (invocation.Arguments);
 253                         Visit (invocation.Expression);
 254                 }
 255         }
 256 }