mcs/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 ExpressionVisitor ()
  37                 {
  38                 }
  39
  40                 protected virtual void Visit (Expression expression)
  41                 {
  42                         if (expression == null)
  43                                 return;
  44
  45                         switch (expression.NodeType) {
  46                         case ExpressionType.Negate:
  47                         case ExpressionType.NegateChecked:
  48                         case ExpressionType.Not:
  49                         case ExpressionType.Convert:
  50                         case ExpressionType.ConvertChecked:
  51                         case ExpressionType.ArrayLength:
  52                         case ExpressionType.Quote:
  53                         case ExpressionType.TypeAs:
  54                         case ExpressionType.UnaryPlus:
  55                                 VisitUnary ((UnaryExpression) expression);
  56                                 break;
  57                         case ExpressionType.Add:
  58                         case ExpressionType.AddChecked:
  59                         case ExpressionType.Subtract:
  60                         case ExpressionType.SubtractChecked:
  61                         case ExpressionType.Multiply:
  62                         case ExpressionType.MultiplyChecked:
  63                         case ExpressionType.Divide:
  64                         case ExpressionType.Modulo:
  65                         case ExpressionType.And:
  66                         case ExpressionType.AndAlso:
  67                         case ExpressionType.Or:
  68                         case ExpressionType.OrElse:
  69                         case ExpressionType.LessThan:
  70                         case ExpressionType.LessThanOrEqual:
  71                         case ExpressionType.GreaterThan:
  72                         case ExpressionType.GreaterThanOrEqual:
  73                         case ExpressionType.Equal:
  74                         case ExpressionType.NotEqual:
  75                         case ExpressionType.Coalesce:
  76                         case ExpressionType.ArrayIndex:
  77                         case ExpressionType.RightShift:
  78                         case ExpressionType.LeftShift:
  79                         case ExpressionType.ExclusiveOr:
  80                                 VisitBinary ((BinaryExpression) expression);
  81                                 break;
  82                         case ExpressionType.TypeIs:
  83                                 VisitTypeIs ((TypeBinaryExpression) expression);
  84                                 break;
  85                         case ExpressionType.Conditional:
  86                                 VisitConditional ((ConditionalExpression) expression);
  87                                 break;
  88                         case ExpressionType.Constant:
  89                                 VisitConstant ((ConstantExpression) expression);
  90                                 break;
  91                         case ExpressionType.Parameter:
  92                                 VisitParameter ((ParameterExpression) expression);
  93                                 break;
  94                         case ExpressionType.MemberAccess:
  95                                 VisitMemberAccess ((MemberExpression) expression);
  96                                 break;
  97                         case ExpressionType.Call:
  98                                 VisitMethodCall ((MethodCallExpression) expression);
  99                                 break;
 100                         case ExpressionType.Lambda:
 101                                 VisitLambda ((LambdaExpression) expression);
 102                                 break;
 103                         case ExpressionType.New:
 104                                 VisitNew ((NewExpression) expression);
 105                                 break;
 106                         case ExpressionType.NewArrayInit:
 107                         case ExpressionType.NewArrayBounds:
 108                                 VisitNewArray ((NewArrayExpression) expression);
 109                                 break;
 110                         case ExpressionType.Invoke:
 111                                 VisitInvocation ((InvocationExpression) expression);
 112                                 break;
 113                         case ExpressionType.MemberInit:
 114                                 VisitMemberInit ((MemberInitExpression) expression);
 115                                 break;
 116                         case ExpressionType.ListInit:
 117                                 VisitListInit ((ListInitExpression) expression);
 118                                 break;
 119                         default:
 120                                 throw new ArgumentException (string.Format ("Unhandled expression type: '{0}'", expression.NodeType));
 121                         }
 122                 }
 123
 124                 protected virtual void VisitBinding (MemberBinding binding)
 125                 {
 126                         switch (binding.BindingType) {
 127                         case MemberBindingType.Assignment:
 128                                 VisitMemberAssignment ((MemberAssignment) binding);
 129                                 break;
 130                         case MemberBindingType.MemberBinding:
 131                                 VisitMemberMemberBinding ((MemberMemberBinding) binding);
 132                                 break;
 133                         case MemberBindingType.ListBinding:
 134                                 VisitMemberListBinding ((MemberListBinding) binding);
 135                                 break;
 136                         default:
 137                                 throw new ArgumentException (string.Format ("Unhandled binding type '{0}'", binding.BindingType));
 138                         }
 139                 }
 140
 141                 protected virtual void VisitElementInitializer (ElementInit initializer)
 142                 {
 143                         VisitExpressionList (initializer.Arguments);
 144                 }
 145
 146                 protected virtual void VisitUnary (UnaryExpression unary)
 147                 {
 148                         Visit (unary.Operand);
 149                 }
 150
 151                 protected virtual void VisitBinary (BinaryExpression binary)
 152                 {
 153                         Visit (binary.Left);
 154                         Visit (binary.Right);
 155                         Visit (binary.Conversion);
 156                 }
 157
 158                 protected virtual void VisitTypeIs (TypeBinaryExpression type)
 159                 {
 160                         Visit (type.Expression);
 161                 }
 162
 163                 protected virtual void VisitConstant (ConstantExpression constant)
 164                 {
 165                 }
 166
 167                 protected virtual void VisitConditional (ConditionalExpression conditional)
 168                 {
 169                         Visit (conditional.Test);
 170                         Visit (conditional.IfTrue);
 171                         Visit (conditional.IfFalse);
 172                 }
 173
 174                 protected virtual void VisitParameter (ParameterExpression parameter)
 175                 {
 176                 }
 177
 178                 protected virtual void VisitMemberAccess (MemberExpression member)
 179                 {
 180                         Visit (member.Expression);
 181                 }
 182
 183                 protected virtual void VisitMethodCall (MethodCallExpression methodCall)
 184                 {
 185                         Visit (methodCall.Object);
 186                         VisitExpressionList (methodCall.Arguments);
 187                 }
 188
 189                 protected virtual void VisitList<T> (ReadOnlyCollection<T> list, Action<T> visitor)
 190                 {
 191                         foreach (T element in list) {
 192                                 visitor (element);
 193                         }
 194                 }
 195
 196                 protected virtual void VisitExpressionList (ReadOnlyCollection<Expression> list)
 197                 {
 198                         VisitList (list, Visit);
 199                 }
 200
 201                 protected virtual void VisitMemberAssignment (MemberAssignment assignment)
 202                 {
 203                         Visit (assignment.Expression);
 204                 }
 205
 206                 protected virtual void VisitMemberMemberBinding (MemberMemberBinding binding)
 207                 {
 208                         VisitBindingList (binding.Bindings);
 209                 }
 210
 211                 protected virtual void VisitMemberListBinding (MemberListBinding binding)
 212                 {
 213                         VisitElementInitializerList (binding.Initializers);
 214                 }
 215
 216                 protected virtual void VisitBindingList (ReadOnlyCollection<MemberBinding> list)
 217                 {
 218                         VisitList (list, VisitBinding);
 219                 }
 220
 221                 protected virtual void VisitElementInitializerList (ReadOnlyCollection<ElementInit> list)
 222                 {
 223                         VisitList (list, VisitElementInitializer);
 224                 }
 225
 226                 protected virtual void VisitLambda (LambdaExpression lambda)
 227                 {
 228                         Visit (lambda.Body);
 229                 }
 230
 231                 protected virtual void VisitNew (NewExpression nex)
 232                 {
 233                         VisitExpressionList (nex.Arguments);
 234                 }
 235
 236                 protected virtual void VisitMemberInit (MemberInitExpression init)
 237                 {
 238                         VisitNew (init.NewExpression);
 239                         VisitBindingList (init.Bindings);
 240                 }
 241
 242                 protected virtual void VisitListInit (ListInitExpression init)
 243                 {
 244                         VisitNew (init.NewExpression);
 245                         VisitElementInitializerList (init.Initializers);
 246                 }
 247
 248                 protected virtual void VisitNewArray (NewArrayExpression newArray)
 249                 {
 250                         VisitExpressionList (newArray.Expressions);
 251                 }
 252
 253                 protected virtual void VisitInvocation (InvocationExpression invocation)
 254                 {
 255                         VisitExpressionList (invocation.Arguments);
 256                         Visit (invocation.Expression);
 257                 }
 258         }
 259 }