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

   1 //
   2 // ExpressionPrinter.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.Generic;
  31 using System.Collections.ObjectModel;
  32 using System.Text;
  33
  34 namespace System.Linq.Expressions {
  35
  36         class ExpressionPrinter : ExpressionVisitor {
  37
  38                 StringBuilder builder;
  39
  40                 const string ListSeparator = ", ";
  41
  42                 ExpressionPrinter (StringBuilder builder)
  43                 {
  44                         this.builder = builder;
  45                 }
  46
  47                 ExpressionPrinter () : this (new StringBuilder ())
  48                 {
  49                 }
  50
  51                 public static string ToString (Expression expression)
  52                 {
  53                         var printer = new ExpressionPrinter ();
  54                         printer.Visit (expression);
  55                         return printer.builder.ToString ();
  56                 }
  57
  58                 public static string ToString (ElementInit init)
  59                 {
  60                         var printer = new ExpressionPrinter ();
  61                         printer.VisitElementInitializer (init);
  62                         return printer.builder.ToString ();
  63                 }
  64
  65                 public static string ToString (MemberBinding binding)
  66                 {
  67                         var printer = new ExpressionPrinter ();
  68                         printer.VisitBinding (binding);
  69                         return printer.builder.ToString ();
  70                 }
  71
  72                 void Print (string str)
  73                 {
  74                         builder.Append (str);
  75                 }
  76
  77                 void Print (object obj)
  78                 {
  79                         builder.Append (obj);
  80                 }
  81
  82                 void Print (string str, params object [] objs)
  83                 {
  84                         builder.AppendFormat (str, objs);
  85                 }
  86
  87                 protected override void VisitElementInitializer (ElementInit initializer)
  88                 {
  89                         Print (initializer.AddMethod);
  90                         Print ("(");
  91                         VisitExpressionList (initializer.Arguments);
  92                         Print (")");
  93                 }
  94
  95                 protected override void VisitUnary (UnaryExpression unary)
  96                 {
  97                         switch (unary.NodeType) {
  98                         case ExpressionType.ArrayLength:
  99                         case ExpressionType.Convert:
 100                         case ExpressionType.ConvertChecked:
 101                         case ExpressionType.Not:
 102                                 Print ("{0}(", unary.NodeType);
 103                                 Visit (unary.Operand);
 104                                 Print (")");
 105                                 return;
 106                         case ExpressionType.Negate:
 107                                 Print ("-");
 108                                 Visit (unary.Operand);
 109                                 return;
 110                         case ExpressionType.Quote:
 111                                 Visit (unary.Operand);
 112                                 return;
 113                         case ExpressionType.TypeAs:
 114                                 Print ("(");
 115                                 Visit (unary.Operand);
 116                                 Print (" As {0})", unary.Type.Name);
 117                                 return;
 118                         case ExpressionType.UnaryPlus:
 119                                 Print ("+");
 120                                 Visit (unary.Operand);
 121                                 return;
 122                         }
 123
 124                         throw new NotImplementedException ();
 125                 }
 126
 127                 static string OperatorToString (BinaryExpression binary)
 128                 {
 129                         switch (binary.NodeType) {
 130                         case ExpressionType.Add:
 131                         case ExpressionType.AddChecked:
 132                                 return "+";
 133                         case ExpressionType.AndAlso:
 134                                 return "&&";
 135                         case ExpressionType.Coalesce:
 136                                 return "??";
 137                         case ExpressionType.Divide:
 138                                 return "/";
 139                         case ExpressionType.Equal:
 140                                 return "=";
 141                         case ExpressionType.ExclusiveOr:
 142                                 return "^";
 143                         case ExpressionType.GreaterThan:
 144                                 return ">";
 145                         case ExpressionType.GreaterThanOrEqual:
 146                                 return ">=";
 147                         case ExpressionType.LeftShift:
 148                                 return "<<";
 149                         case ExpressionType.LessThan:
 150                                 return "<";
 151                         case ExpressionType.LessThanOrEqual:
 152                                 return "<=";
 153                         case ExpressionType.Modulo:
 154                                 return "%";
 155                         case ExpressionType.Multiply:
 156                         case ExpressionType.MultiplyChecked:
 157                                 return "*";
 158                         case ExpressionType.NotEqual:
 159                                 return "!=";
 160                         case ExpressionType.OrElse:
 161                                 return "||";
 162                         case ExpressionType.Power:
 163                                 return "^";
 164                         case ExpressionType.RightShift:
 165                                 return ">>";
 166                         case ExpressionType.Subtract:
 167                         case ExpressionType.SubtractChecked:
 168                                 return "-";
 169                         case ExpressionType.And:
 170                                 return IsBoolean (binary) ? "And" : "&";
 171                         case ExpressionType.Or:
 172                                 return IsBoolean (binary) ? "Or" : "|";
 173                         default:
 174                                 return null;
 175                         }
 176                 }
 177
 178                 static bool IsBoolean (Expression expression)
 179                 {
 180                         return expression.Type == typeof (bool) || expression.Type == typeof (bool?);
 181                 }
 182
 183                 void PrintArrayIndex (BinaryExpression index)
 184                 {
 185                         Visit (index.Left);
 186                         Print ("[");
 187                         Visit (index.Right);
 188                         Print ("]");
 189                 }
 190
 191                 protected override void VisitBinary (BinaryExpression binary)
 192                 {
 193                         switch (binary.NodeType) {
 194                         case ExpressionType.ArrayIndex:
 195                                 PrintArrayIndex (binary);
 196                                 return;
 197                         default:
 198                                 Print ("(");
 199                                 Visit (binary.Left);
 200                                 Print (" {0} ", OperatorToString (binary));
 201                                 Visit (binary.Right);
 202                                 Print (")");
 203                                 return;
 204                         }
 205                 }
 206
 207                 protected override void VisitTypeIs (TypeBinaryExpression type)
 208                 {
 209                         switch (type.NodeType) {
 210                         case ExpressionType.TypeIs:
 211                                 Print ("(");
 212                                 Visit (type.Expression);
 213                                 Print (" Is {0})", type.TypeOperand.Name);
 214                                 return;
 215                         }
 216
 217                         throw new NotImplementedException ();
 218                 }
 219
 220                 protected override void VisitConstant (ConstantExpression constant)
 221                 {
 222                         var value = constant.Value;
 223
 224                         if (value == null) {
 225                                 Print ("null");
 226                         } else if (value is string) {
 227                                 Print ("\"");
 228                                 Print (value);
 229                                 Print ("\"");
 230                         } else if (!HasStringRepresentation (value)) {
 231                                 Print ("value(");
 232                                 Print (value);
 233                                 Print (")");
 234                         } else
 235                                 Print (value);
 236                 }
 237
 238                 static bool HasStringRepresentation (object obj)
 239                 {
 240                         return obj.ToString () != obj.GetType ().ToString ();
 241                 }
 242
 243                 protected override void VisitConditional (ConditionalExpression conditional)
 244                 {
 245                         Print ("IIF(");
 246                         Visit (conditional.Test);
 247                         Print (ListSeparator);
 248                         Visit (conditional.IfTrue);
 249                         Print (ListSeparator);
 250                         Visit (conditional.IfFalse);
 251                         Print (")");
 252                 }
 253
 254                 protected override void VisitParameter (ParameterExpression parameter)
 255                 {
 256                         Print (parameter.Name ?? "<param>");
 257                 }
 258
 259                 protected override void VisitMemberAccess (MemberExpression access)
 260                 {
 261                         if (access.Expression == null)
 262                                 Print (access.Member.DeclaringType.Name);
 263                         else
 264                                 Visit (access.Expression);
 265
 266                         Print (".{0}", access.Member.Name);
 267                 }
 268
 269                 protected override void VisitMethodCall (MethodCallExpression call)
 270                 {
 271                         if (call.Object != null) {
 272                                 Visit (call.Object);
 273                                 Print (".");
 274                         }
 275                         Print (call.Method.Name);
 276                         Print ("(");
 277                         VisitExpressionList (call.Arguments);
 278                         Print (")");
 279                 }
 280
 281                 protected override void VisitMemberAssignment (MemberAssignment assignment)
 282                 {
 283                         Print ("{0} = ", assignment.Member.Name);
 284                         Visit (assignment.Expression);
 285                 }
 286
 287                 protected override void VisitMemberMemberBinding (MemberMemberBinding binding)
 288                 {
 289                         Print (binding.Member.Name);
 290                         Print (" = {");
 291                         // VisitBindingList (binding.Bindings);
 292                         VisitList (binding.Bindings, VisitBinding);
 293                         Print ("}");
 294                 }
 295
 296                 protected override void VisitMemberListBinding (MemberListBinding binding)
 297                 {
 298                         Print (binding.Member.Name);
 299                         Print (" = {");
 300                         // replace when the patch to the visitor is in
 301                         // VisitElementInitializerList (binding.Initializers);
 302                         VisitList (binding.Initializers, VisitElementInitializer);
 303                         Print ("}");
 304                 }
 305
 306                 protected override void VisitList<T> (ReadOnlyCollection<T> list, Action<T> visitor)
 307                 {
 308                         for (int i = 0; i < list.Count; i++) {
 309                                 if (i > 0)
 310                                         Print (ListSeparator);
 311
 312                                 visitor (list [i]);
 313                         }
 314                 }
 315
 316                 protected override void VisitLambda (LambdaExpression lambda)
 317                 {
 318                         if (lambda.Parameters.Count != 1) {
 319                                 Print ("(");
 320                                 // replace when the patch to the visitor is in
 321                                 // VisitExpressionList (lambda.Parameters);
 322                                 VisitList (lambda.Parameters, Visit);
 323                                 Print (")");
 324                         } else
 325                                 Visit (lambda.Parameters [0]);
 326
 327                         Print (" => ");
 328                         Visit (lambda.Body);
 329                 }
 330
 331                 protected override void VisitNew (NewExpression nex)
 332                 {
 333                         Print ("new {0}(", nex.Type.Name);
 334                         if (nex.Members != null && nex.Members.Count > 0) {
 335                                 for (int i = 0; i < nex.Members.Count; i++) {
 336                                         if (i > 0)
 337                                                 Print (ListSeparator);
 338
 339                                         Print ("{0} = ", nex.Members [i].Name);
 340                                         Visit (nex.Arguments [i]);
 341                                 }
 342                         } else
 343                                 VisitExpressionList (nex.Arguments);
 344                         Print (")");
 345                 }
 346
 347                 protected override void VisitMemberInit (MemberInitExpression init)
 348                 {
 349                         Visit (init.NewExpression);
 350                         Print (" {");
 351                         // VisitBindingList (init.Bindings)
 352                         VisitList (init.Bindings, VisitBinding);
 353                         Print ("}");
 354                 }
 355
 356                 protected override void VisitListInit (ListInitExpression init)
 357                 {
 358                         Visit (init.NewExpression);
 359                         Print (" {");
 360                         // VisitElementInitializerList
 361                         VisitList (init.Initializers, VisitElementInitializer);
 362                         Print ("}");
 363                 }
 364
 365                 protected override void VisitNewArray (NewArrayExpression newArray)
 366                 {
 367                         Print ("new ");
 368                         switch (newArray.NodeType) {
 369                         case ExpressionType.NewArrayBounds:
 370                                 Print (newArray.Type);
 371                                 Print ("(");
 372                                 VisitExpressionList (newArray.Expressions);
 373                                 Print (")");
 374                                 return;
 375                         case ExpressionType.NewArrayInit:
 376                                 Print ("[] {");
 377                                 VisitExpressionList (newArray.Expressions);
 378                                 Print ("}");
 379                                 return;
 380                         }
 381
 382                         throw new NotSupportedException ();
 383                 }
 384
 385                 protected override void VisitInvocation (InvocationExpression invocation)
 386                 {
 387                         Print ("Invoke(");
 388                         Visit (invocation.Expression);
 389
 390                         if (invocation.Arguments.Count != 0) {
 391                                 Print (ListSeparator);
 392                                 VisitExpressionList (invocation.Arguments);
 393                         }
 394
 395                         Print (")");
 396                 }
 397         }
 398 }