mcs/class/System.XML/System.Xml.XPath/Expression.cs

   1 //
   2 // System.Xml.XPath.XPathExpression support classes
   3 //
   4 // Author:
   5 //   Piers Haken (piersh@friskit.com)
   6 //
   7 // (C) 2002 Piers Haken
   8 //
   9 using System;
  10 using System.IO;
  11 using System.Collections;
  12 using System.Xml;
  13 using System.Xml.XPath;
  14 using System.Xml.Xsl;
  15 using System.Globalization;
  16 using Mono.Xml.XPath;
  17
  18 namespace System.Xml.XPath
  19 {
  20 #if XPATH_DEBUG
  21         internal class CompiledExpression : Test.Xml.XPath.XPathExpression
  22 #else
  23         internal class CompiledExpression : XPathExpression
  24 #endif
  25         {
  26                 protected XmlNamespaceManager _nsm;
  27                 protected Expression _expr;
  28                 XPathSorters _sorters;
  29
  30                 public CompiledExpression (Expression expr)
  31                 {
  32                         _expr = expr;
  33                 }
  34                 private CompiledExpression (CompiledExpression other)
  35                 {
  36                         _nsm = other._nsm;
  37                         _expr = other._expr;
  38                 }
  39 #if XPATH_DEBUG
  40                 public override Test.Xml.XPath.XPathExpression Clone () { return new CompiledExpression (this); }
  41 #else
  42                 public override XPathExpression Clone () { return new CompiledExpression (this); }
  43 #endif
  44
  45                 public Expression ExpressionNode { get { return _expr; }}
  46
  47                 public override void SetContext (XmlNamespaceManager nsManager)
  48                 {
  49                         _nsm = nsManager;
  50                 }
  51                 internal XmlNamespaceManager NamespaceManager { get { return _nsm; } }
  52                 public override String Expression { get { return _expr.ToString (); }}
  53                 public override XPathResultType ReturnType { get { return _expr.ReturnType; }}
  54
  55                 public object Evaluate (BaseIterator iter)
  56                 {
  57                         if (_sorters != null)
  58                                 return EvaluateNodeSet (iter);
  59
  60                         try
  61                         {
  62                                 return _expr.Evaluate (iter);
  63                         }
  64                         catch (XPathException)
  65                         {
  66                                 throw;
  67                         }
  68                         catch (Exception e)
  69                         {
  70                                 throw new XPathException ("Error during evaluation", e);
  71                         }
  72                 }
  73                 public XPathNodeIterator EvaluateNodeSet (BaseIterator iter)
  74                 {
  75                         try
  76                         {
  77                                 BaseIterator iterResults = (BaseIterator) _expr.EvaluateNodeSet (iter);
  78                                 if (_sorters != null)
  79                                         return _sorters.Sort (iterResults);
  80                                 return iterResults;
  81                         }
  82                         catch (XPathException)
  83                         {
  84                                 throw;
  85                         }
  86                         catch (Exception e)
  87                         {
  88                                 throw new XPathException ("Error during evaluation", e);
  89                         }
  90                 }
  91                 public double EvaluateNumber (BaseIterator iter)
  92                 {
  93                         try
  94                         {
  95                                 return _expr.EvaluateNumber (iter);
  96                         }
  97                         catch (XPathException)
  98                         {
  99                                 throw;
 100                         }
 101                         catch (Exception e)
 102                         {
 103                                 throw new XPathException ("Error during evaluation", e);
 104                         }
 105                 }
 106                 public string EvaluateString (BaseIterator iter)
 107                 {
 108                         try
 109                         {
 110                                 return _expr.EvaluateString (iter);
 111                         }
 112                         catch (XPathException)
 113                         {
 114                                 throw;
 115                         }
 116                         catch (Exception e)
 117                         {
 118                                 throw new XPathException ("Error during evaluation", e);
 119                         }
 120                 }
 121                 public bool EvaluateBoolean (BaseIterator iter)
 122                 {
 123                         try
 124                         {
 125                                 return _expr.EvaluateBoolean (iter);
 126                         }
 127                         catch (XPathException)
 128                         {
 129                                 throw;
 130                         }
 131                         catch (Exception e)
 132                         {
 133                                 throw new XPathException ("Error during evaluation", e);
 134                         }
 135                 }
 136
 137                 public override void AddSort (Object obj, IComparer cmp)
 138                 {
 139                         if (_sorters == null)
 140                                 _sorters = new XPathSorters ();
 141                         _sorters.Add (obj, cmp);
 142                 }
 143                 public override void AddSort(object expr, XmlSortOrder orderSort, XmlCaseOrder orderCase, string lang, XmlDataType dataType)
 144                 {
 145                         if (_sorters == null)
 146                                 _sorters = new XPathSorters ();
 147                         _sorters.Add (expr, orderSort, orderCase, lang, dataType);
 148                 }
 149
 150                 class XPathSorters : IComparer
 151                 {
 152                         readonly ArrayList _rgSorters = new ArrayList ();
 153
 154                         public void Add (object expr, IComparer cmp)
 155                         {
 156                                 _rgSorters.Add (new XPathSorter (expr, cmp));
 157                         }
 158
 159                         public void Add (object expr, XmlSortOrder orderSort, XmlCaseOrder orderCase, string lang, XmlDataType dataType)
 160                         {
 161                                 _rgSorters.Add (new XPathSorter (expr, orderSort, orderCase, lang, dataType));
 162                         }
 163
 164                         public BaseIterator Sort (BaseIterator iter)
 165                         {
 166                                 ArrayList rgElts = new ArrayList ();
 167                                 int cSorters = _rgSorters.Count;
 168                                 while (iter.MoveNext ())
 169                                 {
 170                                         XPathSortElement elt = new XPathSortElement ();
 171                                         elt.Navigator = iter.Current.Clone ();
 172                                         elt.Values = new object [cSorters];
 173                                         for (int iSorter = 0; iSorter < _rgSorters.Count; ++iSorter)
 174                                         {
 175                                                 XPathSorter sorter = (XPathSorter) _rgSorters [iSorter];
 176                                                 elt.Values [iSorter] = sorter.Evaluate (iter);
 177                                         }
 178                                         rgElts.Add (elt);
 179                                 }
 180                                 rgElts.Sort (this);
 181                                 XPathNavigator [] rgResults = new XPathNavigator [rgElts.Count];
 182                                 for (int iResult = 0; iResult < rgElts.Count; ++iResult)
 183                                 {
 184                                         XPathSortElement elt = (XPathSortElement) rgElts [iResult];
 185                                         rgResults [iResult] = elt.Navigator;
 186                                 }
 187                                 return new ListIterator (iter, rgResults, false);
 188                         }
 189
 190                         class XPathSortElement
 191                         {
 192                                 public XPathNavigator Navigator;
 193                                 public object [] Values;
 194                         }
 195
 196                         int IComparer.Compare (object o1, object o2)
 197                         {
 198                                 XPathSortElement elt1 = (XPathSortElement) o1;
 199                                 XPathSortElement elt2 = (XPathSortElement) o2;
 200                                 for (int iSorter = 0; iSorter < _rgSorters.Count; ++iSorter)
 201                                 {
 202                                         XPathSorter sorter = (XPathSorter) _rgSorters [iSorter];
 203                                         int cmp = sorter.Compare (elt1.Values [iSorter], elt2.Values [iSorter]);
 204                                         if (cmp != 0)
 205                                                 return cmp;
 206                                 }
 207                                 switch (elt1.Navigator.ComparePosition (elt2.Navigator)) {
 208                                 case XmlNodeOrder.Same:
 209                                         return 0;
 210                                 case XmlNodeOrder.After:
 211                                         return 1;
 212                                 default:
 213                                         return -1;
 214                                 }
 215                         }
 216
 217                         class XPathSorter
 218                         {
 219                                 readonly Expression _expr;
 220                                 readonly IComparer _cmp;
 221                                 readonly XmlDataType _type;
 222
 223                                 public XPathSorter (object expr, IComparer cmp)
 224                                 {
 225                                         _expr = ExpressionFromObject (expr);
 226                                         _cmp = cmp;
 227                                         _type = XmlDataType.Text;
 228                                 }
 229
 230                                 public XPathSorter (object expr, XmlSortOrder orderSort, XmlCaseOrder orderCase, string lang, XmlDataType dataType)
 231                                 {
 232                                         _expr = ExpressionFromObject (expr);
 233                                         _type = dataType;
 234                                         if (dataType == XmlDataType.Number)
 235                                                 _cmp = new XPathNumberComparer (orderSort);
 236                                         else
 237                                                 _cmp = new XPathTextComparer (orderSort, orderCase, lang);
 238                                 }
 239
 240                                 static Expression ExpressionFromObject (object expr)
 241                                 {
 242                                         if (expr is CompiledExpression)
 243                                                 return ((CompiledExpression) expr)._expr;
 244                                         if (expr is string)
 245                                                 return new XPathParser ().Compile ((string)expr);
 246
 247                                         throw new XPathException ("Invalid query object");
 248                                 }
 249
 250                                 public object Evaluate (BaseIterator iter)
 251                                 {
 252                                         if (_type == XmlDataType.Number)
 253                                                 return _expr.EvaluateNumber (iter);
 254                                         return _expr.EvaluateString (iter);
 255                                 }
 256
 257                                 public int Compare (object o1, object o2)
 258                                 {
 259                                         return _cmp.Compare (o1, o2);
 260                                 }
 261
 262                                 class XPathNumberComparer : IComparer
 263                                 {
 264                                         int _nMulSort;
 265
 266                                         public XPathNumberComparer (XmlSortOrder orderSort)
 267                                         {
 268                                                 _nMulSort = (orderSort == XmlSortOrder.Ascending) ? 1 : -1;
 269                                         }
 270
 271                                         int IComparer.Compare (object o1, object o2)
 272                                         {
 273                                                 double num1 = (double) o1;
 274                                                 double num2 = (double) o2;
 275                                                 if (num1 < num2)
 276                                                         return -_nMulSort;
 277                                                 if (num1 > num2)
 278                                                         return _nMulSort;
 279                                                 if (num1 == num2)
 280                                                         return 0;
 281                                                 if (double.IsNaN (num1))
 282                                                         return (double.IsNaN (num2)) ? 0 : -_nMulSort;
 283                                                 return _nMulSort;
 284                                         }
 285                                 }
 286
 287                                 class XPathTextComparer : IComparer
 288                                 {
 289                                         int _nMulSort;
 290                                         int _nMulCase;
 291                                         XmlCaseOrder _orderCase;
 292                                         CultureInfo _ci;
 293
 294                                         public XPathTextComparer (XmlSortOrder orderSort, XmlCaseOrder orderCase, string strLang)
 295                                         {
 296                                                 _orderCase = orderCase;
 297                                                 _nMulCase = (orderCase == XmlCaseOrder.UpperFirst) ? -1 : 1;
 298
 299                                                 _nMulSort = (orderSort == XmlSortOrder.Ascending) ? 1 : -1;
 300
 301                                                 if (strLang == null || strLang == "")
 302                                                         _ci = CultureInfo.CurrentCulture;       // TODO: defer until evaluation?
 303                                                 else
 304                                                         _ci = new CultureInfo (strLang);
 305                                         }
 306
 307                                         int IComparer.Compare (object o1, object o2)
 308                                         {
 309                                                 string str1 = (string) o1;
 310                                                 string str2 = (string) o2;
 311                                                 int cmp = String.Compare (str1, str2, true, _ci);
 312                                                 if (cmp != 0 || _orderCase == XmlCaseOrder.None)
 313                                                         return cmp * _nMulSort;
 314                                                 return _nMulSort * _nMulCase * String.Compare (str1, str2, false, _ci);
 315                                         }
 316                                 }
 317                         }
 318                 }
 319         }
 320
 321
 322         /// <summary>
 323         /// Summary description for Expression.
 324         /// </summary>
 325         internal abstract class Expression
 326         {
 327                 public Expression ()
 328                 {
 329                 }
 330                 public abstract XPathResultType ReturnType { get; }
 331                 public virtual XPathResultType GetReturnType (BaseIterator iter) { return ReturnType; }
 332                 public abstract object Evaluate (BaseIterator iter);
 333
 334                 public virtual BaseIterator EvaluateNodeSet (BaseIterator iter)
 335                 {
 336                         XPathResultType type = GetReturnType (iter);
 337                         if (type == XPathResultType.NodeSet ||
 338                                 type == XPathResultType.Any)
 339                         {
 340                                 BaseIterator iterResult = Evaluate (iter) as BaseIterator;
 341                                 if (iterResult != null)
 342                                         return iterResult;
 343                         }
 344                         throw new XPathException ("expected nodeset: "+ToString ());
 345                 }
 346
 347                 protected static XPathResultType GetReturnType (object obj)
 348                 {
 349                         if (obj is string)
 350                                 return XPathResultType.String;
 351                         if (obj is bool)
 352                                 return XPathResultType.Boolean;
 353                         if (obj is XPathNodeIterator)
 354                                 return XPathResultType.NodeSet;
 355                         if (obj is double || obj is int)
 356                                 return XPathResultType.Number;
 357                         throw new XPathException ("invalid node type: "+obj.GetType ().ToString ());
 358                 }
 359
 360                 internal virtual XPathNodeType EvaluatedNodeType {
 361                         get { return XPathNodeType.All; }
 362                 }
 363
 364                 internal virtual bool NeedAbsoluteMatching {
 365                         get { return false; }
 366                 }
 367
 368                 internal virtual bool IsPositional {
 369                         get { return false; }
 370                 }
 371
 372                 [MonoTODO]
 373                 public virtual double EvaluateNumber (BaseIterator iter)
 374                 {
 375                         object result;
 376                         XPathResultType type = GetReturnType (iter);
 377                         if (type == XPathResultType.NodeSet)
 378                         {
 379                                 result = EvaluateString (iter);
 380                                 type = XPathResultType.String;
 381                         }
 382                         else
 383                                 result = Evaluate (iter);
 384
 385                         if (type == XPathResultType.Any)
 386                                 type = GetReturnType (result);
 387
 388                         switch (type)
 389                         {
 390                                 case XPathResultType.Number:
 391                                         return (double)result;
 392                                 case XPathResultType.Boolean:
 393                                         return ((bool) result) ? 1.0 : 0.0;
 394                                 case XPathResultType.NodeSet:
 395                                         return XPathFunctions.ToNumber (EvaluateString (iter));
 396                                 case XPathResultType.String:
 397                                         return XPathFunctions.ToNumber ((string) result);       // TODO: spec? convert string to number
 398                                 default:
 399                                         throw new XPathException ("invalid node type"); // TODO: handle other types
 400                         }
 401                 }
 402                 [MonoTODO]
 403                 public virtual string EvaluateString (BaseIterator iter)
 404                 {
 405                         object result = Evaluate (iter);
 406                         XPathResultType type = GetReturnType (iter);
 407                         if (type == XPathResultType.Any)
 408                                 type = GetReturnType (result);
 409                         switch (type)
 410                         {
 411                                 case XPathResultType.Number:
 412                                         return (string) XmlConvert.ToString ((double)result);   // TODO: spec? convert number to string
 413                                 case XPathResultType.Boolean:
 414                                         return ((bool) result) ? "true" : "false";
 415                                 case XPathResultType.String:
 416                                         return (string) result;
 417                                 case XPathResultType.NodeSet:
 418                                 {
 419                                         BaseIterator iterResult = (BaseIterator) result;
 420                                         if (iterResult == null || !iterResult.MoveNext ())
 421                                                 return "";
 422                                         return iterResult.Current.Value;
 423                                 }
 424                                 default:
 425                                         throw new XPathException ("invalid node type"); // TODO: handle other types
 426                         }
 427                 }
 428                 [MonoTODO]
 429                 public virtual bool EvaluateBoolean (BaseIterator iter)
 430                 {
 431                         object result = Evaluate (iter);
 432                         XPathResultType type = GetReturnType (iter);
 433                         if (type == XPathResultType.Any)
 434                                 type = GetReturnType (result);
 435                         switch (type)
 436                         {
 437                                 case XPathResultType.Number:
 438                                 {
 439                                         double num = Convert.ToDouble (result);
 440                                         return (num != 0.0 && num != -0.0 && !Double.IsNaN (num));
 441                                 }
 442                                 case XPathResultType.Boolean:
 443                                         return (bool) result;
 444                                 case XPathResultType.String:
 445                                         return ((string) result).Length != 0;
 446                                 case XPathResultType.NodeSet:
 447                                 {
 448                                         BaseIterator iterResult = (BaseIterator) result;
 449                                         return (iterResult != null && iterResult.MoveNext ());
 450                                 }
 451                                 default:
 452                                         throw new XPathException ("invalid node type"); // TODO: handle other types
 453                         }
 454                 }
 455                 public object EvaluateAs (BaseIterator iter, XPathResultType type)
 456                 {
 457                         switch (type)
 458                         {
 459                         case XPathResultType.Boolean:
 460                                 return EvaluateBoolean (iter);
 461                         case XPathResultType.NodeSet:
 462                                 return EvaluateNodeSet (iter);
 463                         case XPathResultType.String:
 464                                 return EvaluateString (iter);
 465                         case XPathResultType.Number:
 466                                 return EvaluateNumber (iter);
 467                         }
 468                         return Evaluate (iter);
 469                 }
 470
 471                 public virtual bool RequireSorting { get { return false; } }
 472         }
 473
 474         internal abstract class ExprBinary : Expression
 475         {
 476                 protected Expression _left, _right;
 477
 478                 public ExprBinary (Expression left, Expression right)
 479                 {
 480                         _left = left;
 481                         _right = right;
 482                 }
 483                 public override String ToString ()
 484                 {
 485                         return _left.ToString () + ' ' + Operator + ' ' + _right.ToString ();
 486                 }
 487                 protected abstract String Operator { get; }
 488
 489                 internal override XPathNodeType EvaluatedNodeType {
 490                         get {
 491                                 if (_left.EvaluatedNodeType == _right.EvaluatedNodeType)
 492                                         return _left.EvaluatedNodeType;
 493                                 else
 494                                         return XPathNodeType.All;
 495                         }
 496                 }
 497
 498                 internal override bool IsPositional {
 499                         get { return _left.IsPositional || _right.IsPositional; }
 500                 }
 501         }
 502
 503         internal abstract class ExprBoolean : ExprBinary
 504         {
 505                 public ExprBoolean (Expression left, Expression right) : base (left, right) {}
 506                 public override XPathResultType ReturnType { get { return XPathResultType.Boolean; }}
 507                 public override object Evaluate (BaseIterator iter)
 508                 {
 509                         return EvaluateBoolean (iter);
 510                 }
 511                 public override double EvaluateNumber (BaseIterator iter)
 512                 {
 513                         return EvaluateBoolean (iter) ? 1 : 0;
 514                 }
 515
 516                 public override string EvaluateString (BaseIterator iter)
 517                 {
 518                         return EvaluateBoolean (iter) ? "true" : "false";
 519                 }
 520         }
 521
 522         internal class ExprOR : ExprBoolean
 523         {
 524                 public ExprOR (Expression left, Expression right) : base (left, right) {}
 525                 protected override String Operator { get { return "or"; }}
 526                 public override bool EvaluateBoolean (BaseIterator iter)
 527                 {
 528                         if (_left.EvaluateBoolean (iter))
 529                                 return true;
 530                         return _right.EvaluateBoolean (iter);
 531                 }
 532         }
 533
 534         internal class ExprAND : ExprBoolean
 535         {
 536                 public ExprAND (Expression left, Expression right) : base (left, right) {}
 537                 protected override String Operator { get { return "and"; }}
 538                 public override bool EvaluateBoolean (BaseIterator iter)
 539                 {
 540                         if (!_left.EvaluateBoolean (iter))
 541                                 return false;
 542                         return _right.EvaluateBoolean (iter);
 543                 }
 544         }
 545
 546         internal abstract class EqualityExpr : ExprBoolean
 547         {
 548                 bool trueVal;
 549                 public EqualityExpr (Expression left, Expression right, bool trueVal) : base (left, right)
 550                 {
 551                         this.trueVal = trueVal;
 552                 }
 553                 [MonoTODO]
 554                 public override bool EvaluateBoolean (BaseIterator iter)
 555                 {
 556                         XPathResultType typeL = _left.GetReturnType (iter);
 557                         XPathResultType typeR = _right.GetReturnType (iter);
 558
 559                         // TODO: avoid double evaluations
 560                         if (typeL == XPathResultType.Any)
 561                                 typeL = GetReturnType (_left.Evaluate (iter));
 562                         if (typeR == XPathResultType.Any)
 563                                 typeR = GetReturnType (_right.Evaluate (iter));
 564
 565                         if (typeL == XPathResultType.NodeSet || typeR == XPathResultType.NodeSet)
 566                         {
 567                                 Expression left, right;
 568                                 if (typeL != XPathResultType.NodeSet)
 569                                 {
 570                                         left = _right;
 571                                         right = _left;
 572                                         XPathResultType typeTmp = typeL;
 573                                         typeL = typeR;
 574                                         typeR = typeTmp;
 575                                 }
 576                                 else
 577                                 {
 578                                         left = _left;
 579                                         right = _right;
 580                                 }
 581                                 if (typeR == XPathResultType.Boolean)
 582                                 {
 583                                         return left.EvaluateBoolean (iter) == right.EvaluateBoolean (iter) == trueVal;
 584                                 }
 585                                 else
 586                                 {
 587                                         BaseIterator iterL = left.EvaluateNodeSet (iter);
 588                                         if (typeR == XPathResultType.Number)
 589                                         {
 590                                                 double dR = right.EvaluateNumber (iter);
 591                                                 while (iterL.MoveNext ())
 592                                                         if (XPathFunctions.ToNumber (iterL.Current.Value) == dR == trueVal)
 593                                                                 return true;
 594                                         }
 595                                         else if (typeR == XPathResultType.String)
 596                                         {
 597                                                 string strR = right.EvaluateString (iter);
 598                                                 while (iterL.MoveNext ())
 599                                                         if (iterL.Current.Value == strR == trueVal)
 600                                                                 return true;
 601                                         }
 602                                         else if (typeR == XPathResultType.NodeSet)
 603                                         {
 604                                                 BaseIterator iterR = right.EvaluateNodeSet (iter);
 605                                                 ArrayList rgNodesL = new ArrayList ();
 606                                                 while (iterL.MoveNext ())
 607                                                         rgNodesL.Add (XPathFunctions.ToString (iterL.Current.Value));
 608                                                 while (iterR.MoveNext ())
 609                                                 {
 610                                                         string strR = XPathFunctions.ToString (iterR.Current.Value);
 611                                                         for (int l = 0; l < rgNodesL.Count; l++)
 612                                                                 if ((strR == (string) rgNodesL [l]) == trueVal)
 613                                                                         return true;
 614                                                 }
 615                                         }
 616                                         return false;
 617                                 }
 618                         }
 619                         else if (typeL == XPathResultType.Boolean || typeR == XPathResultType.Boolean)
 620                                 return _left.EvaluateBoolean (iter) == _right.EvaluateBoolean (iter) == trueVal;
 621                         else if (typeL == XPathResultType.Number || typeR == XPathResultType.Number)
 622                                 return _left.EvaluateNumber (iter) == _right.EvaluateNumber (iter) == trueVal;
 623                         else
 624                                 return _left.EvaluateString (iter) == _right.EvaluateString (iter) == trueVal;
 625                 }
 626         }
 627
 628         internal class ExprEQ : EqualityExpr
 629         {
 630                 public ExprEQ (Expression left, Expression right) : base (left, right, true) {}
 631                 protected override String Operator { get { return "="; }}
 632         }
 633
 634         internal class ExprNE : EqualityExpr
 635         {
 636                 public ExprNE (Expression left, Expression right) : base (left, right, false) {}
 637                 protected override String Operator { get { return "!="; }}
 638         }
 639
 640         internal abstract class RelationalExpr : ExprBoolean
 641         {
 642                 public RelationalExpr (Expression left, Expression right) : base (left, right) {}
 643                 [MonoTODO]
 644                 public override bool EvaluateBoolean (BaseIterator iter)
 645                 {
 646                         XPathResultType typeL = _left.GetReturnType (iter);
 647                         XPathResultType typeR = _right.GetReturnType (iter);
 648
 649                         // TODO: avoid double evaluations
 650                         if (typeL == XPathResultType.Any)
 651                                 typeL = GetReturnType (_left.Evaluate (iter));
 652                         if (typeR == XPathResultType.Any)
 653                                 typeR = GetReturnType (_right.Evaluate (iter));
 654
 655                         if (typeL == XPathResultType.NodeSet || typeR == XPathResultType.NodeSet)
 656                         {
 657                                 bool fReverse = false;
 658                                 Expression left, right;
 659                                 if (typeL != XPathResultType.NodeSet)
 660                                 {
 661                                         fReverse = true;
 662                                         left = _right;
 663                                         right = _left;
 664                                         XPathResultType typeTmp = typeL;
 665                                         typeL = typeR;
 666                                         typeR = typeTmp;
 667                                 }
 668                                 else
 669                                 {
 670                                         left = _left;
 671                                         right = _right;
 672                                 }
 673                                 if (typeR == XPathResultType.Boolean)
 674                                 {
 675                                         bool fL = left.EvaluateBoolean (iter);
 676                                         bool fR = right.EvaluateBoolean (iter);
 677                                         return Compare (Convert.ToDouble (fL), Convert.ToDouble (fR), fReverse);
 678                                 }
 679                                 else
 680                                 {
 681                                         BaseIterator iterL = left.EvaluateNodeSet (iter);
 682                                         if (typeR == XPathResultType.Number || typeR == XPathResultType.String)
 683                                         {
 684                                                 double dR = right.EvaluateNumber (iter);
 685                                                 while (iterL.MoveNext ())
 686                                                         if (Compare (XPathFunctions.ToNumber (iterL.Current.Value), dR, fReverse))
 687                                                                 return true;
 688                                         }
 689                                         else if (typeR == XPathResultType.NodeSet)
 690                                         {
 691                                                 BaseIterator iterR = right.EvaluateNodeSet (iter);
 692                                                 ArrayList rgNodesL = new ArrayList ();
 693                                                 while (iterL.MoveNext ())
 694                                                         rgNodesL.Add (XPathFunctions.ToNumber (iterL.Current.Value));
 695                                                 while (iterR.MoveNext ())
 696                                                 {
 697                                                         double numR = XPathFunctions.ToNumber (iterR.Current.Value);
 698                                                         for (int l = 0; l < rgNodesL.Count; l++)
 699                                                                 if (Compare (numR, (double) rgNodesL [l]))
 700                                                                         return true;
 701                                                 }
 702                                         }
 703                                         return false;
 704                                 }
 705                         }
 706                         else
 707                                 return Compare (_left.EvaluateNumber (iter), _right.EvaluateNumber (iter));
 708                 }
 709                 public abstract bool Compare (double arg1, double arg2);
 710                 public bool Compare (double arg1, double arg2, bool fReverse)
 711                 {
 712                         if (fReverse)
 713                                 return Compare (arg2, arg1);
 714                         else
 715                                 return Compare (arg1, arg2);
 716                 }
 717         }
 718
 719         internal class ExprGT : RelationalExpr
 720         {
 721                 public ExprGT (Expression left, Expression right) : base (left, right) {}
 722                 protected override String Operator { get { return ">"; }}
 723                 public override bool Compare (double arg1, double arg2)
 724                 {
 725                         return arg1 > arg2;
 726                 }
 727         }
 728
 729         internal class ExprGE : RelationalExpr
 730         {
 731                 public ExprGE (Expression left, Expression right) : base (left, right) {}
 732                 protected override String Operator { get { return ">="; }}
 733                 public override bool Compare (double arg1, double arg2)
 734                 {
 735                         return arg1 >= arg2;
 736                 }
 737         }
 738
 739         internal class ExprLT : RelationalExpr
 740         {
 741                 public ExprLT (Expression left, Expression right) : base (left, right) {}
 742                 protected override String Operator { get { return "<"; }}
 743                 public override bool Compare (double arg1, double arg2)
 744                 {
 745                         return arg1 < arg2;
 746                 }
 747         }
 748
 749         internal class ExprLE : RelationalExpr
 750         {
 751                 public ExprLE (Expression left, Expression right) : base (left, right) {}
 752                 protected override String Operator { get { return "<="; }}
 753                 public override bool Compare (double arg1, double arg2)
 754                 {
 755                         return arg1 <= arg2;
 756                 }
 757         }
 758
 759         internal abstract class ExprNumeric : ExprBinary
 760         {
 761                 public ExprNumeric (Expression left, Expression right) : base (left, right) {}
 762                 public override XPathResultType ReturnType { get { return XPathResultType.Number; }}
 763
 764                 public override object Evaluate (BaseIterator iter)
 765                 {
 766                         return EvaluateNumber (iter);
 767                 }
 768         }
 769
 770         internal class ExprPLUS : ExprNumeric
 771         {
 772                 public ExprPLUS (Expression left, Expression right) : base (left, right) {}
 773                 protected override String Operator { get { return "+"; }}
 774                 public override double EvaluateNumber (BaseIterator iter)
 775                 {
 776                         return _left.EvaluateNumber (iter) + _right.EvaluateNumber (iter);
 777                 }
 778         }
 779
 780         internal class ExprMINUS : ExprNumeric
 781         {
 782                 public ExprMINUS (Expression left, Expression right) : base (left, right) {}
 783                 protected override String Operator { get { return "-"; }}
 784                 public override double EvaluateNumber (BaseIterator iter)
 785                 {
 786                         return _left.EvaluateNumber (iter) - _right.EvaluateNumber (iter);
 787                 }
 788         }
 789
 790         internal class ExprMULT : ExprNumeric
 791         {
 792                 public ExprMULT (Expression left, Expression right) : base (left, right) {}
 793                 protected override String Operator { get { return "*"; }}
 794                 public override double EvaluateNumber (BaseIterator iter)
 795                 {
 796                         return _left.EvaluateNumber (iter) * _right.EvaluateNumber (iter);
 797                 }
 798         }
 799
 800         internal class ExprDIV : ExprNumeric
 801         {
 802                 public ExprDIV (Expression left, Expression right) : base (left, right) {}
 803                 protected override String Operator { get { return " div "; }}
 804                 public override double EvaluateNumber (BaseIterator iter)
 805                 {
 806                         return _left.EvaluateNumber (iter) / _right.EvaluateNumber (iter);
 807                 }
 808         }
 809
 810         internal class ExprMOD : ExprNumeric
 811         {
 812                 public ExprMOD (Expression left, Expression right) : base (left, right) {}
 813                 protected override String Operator { get { return "%"; }}
 814                 [MonoTODO]
 815                 public override double EvaluateNumber (BaseIterator iter)
 816                 {
 817                         return _left.EvaluateNumber (iter) % _right.EvaluateNumber (iter);      // TODO: spec?
 818                 }
 819         }
 820
 821         internal class ExprNEG : Expression
 822         {
 823                 Expression _expr;
 824                 public ExprNEG (Expression expr)
 825                 {
 826                         _expr = expr;
 827                 }
 828                 public override String ToString () { return "- " + _expr.ToString (); }
 829                 public override XPathResultType ReturnType { get { return XPathResultType.Number; }}
 830                 public override object Evaluate (BaseIterator iter)
 831                 {
 832                         return - _expr.EvaluateNumber (iter);
 833                 }
 834
 835                 public override double EvaluateNumber (BaseIterator iter)
 836                 {
 837                         return - _expr.EvaluateNumber (iter);
 838                 }
 839
 840                 internal override bool IsPositional {
 841                         get { return _expr.IsPositional; }
 842                 }
 843         }
 844
 845
 846         internal abstract class NodeSet : Expression
 847         {
 848                 public override XPathResultType ReturnType { get { return XPathResultType.NodeSet; }}
 849         }
 850
 851         internal class ExprUNION : NodeSet
 852         {
 853                 public readonly Expression left, right;
 854                 public ExprUNION (Expression left, Expression right)
 855                 {
 856                         this.left = left;
 857                         this.right = right;
 858                 }
 859                 public override String ToString () { return left.ToString ()+ " | " + right.ToString (); }
 860                 public override object Evaluate (BaseIterator iter)
 861                 {
 862                         BaseIterator iterLeft = left.EvaluateNodeSet (iter);
 863                         BaseIterator iterRight = right.EvaluateNodeSet (iter);
 864                         return new UnionIterator (iter, iterLeft, iterRight);
 865                 }
 866
 867                 internal override bool NeedAbsoluteMatching {
 868                         get { return left.NeedAbsoluteMatching || right.NeedAbsoluteMatching; }
 869                 }
 870
 871                 internal override XPathNodeType EvaluatedNodeType {
 872                         get { return left.EvaluatedNodeType == right.EvaluatedNodeType ? left.EvaluatedNodeType : XPathNodeType.All; }
 873                 }
 874
 875                 internal override bool IsPositional {
 876                         get { return left.IsPositional || right.IsPositional; }
 877                 }
 878         }
 879
 880         internal class ExprSLASH : NodeSet
 881         {
 882                 public readonly Expression left;
 883                 public readonly NodeSet right;
 884                 public ExprSLASH (Expression left, NodeSet right)
 885                 {
 886                         this.left = left;
 887                         this.right = right;
 888                 }
 889                 public override String ToString () { return left.ToString ()+ "/" + right.ToString (); }
 890                 public override object Evaluate (BaseIterator iter)
 891                 {
 892                         BaseIterator iterLeft = left.EvaluateNodeSet (iter);
 893                         return new SlashIterator (iterLeft, right);
 894                 }
 895
 896                 public override bool RequireSorting { get { return left.RequireSorting || right.RequireSorting; } }
 897
 898                 internal override bool NeedAbsoluteMatching {
 899                         get { return true; }
 900                 }
 901
 902                 internal override XPathNodeType EvaluatedNodeType {
 903                         get { return right.EvaluatedNodeType; }
 904                 }
 905
 906                 internal override bool IsPositional {
 907                         get { return left.IsPositional || right.IsPositional; }
 908                 }
 909         }
 910
 911         internal class ExprSLASH2 : NodeSet {
 912                 public readonly Expression left;
 913                 public readonly NodeSet right;
 914
 915                 static NodeTest DescendantOrSelfStar = new NodeTypeTest (Axes.DescendantOrSelf, XPathNodeType.All);
 916
 917                 public ExprSLASH2 (Expression left, NodeSet right)
 918                 {
 919                         this.left = left;
 920                         this.right = right;
 921                 }
 922                 public override String ToString () { return left.ToString ()+ "//" + right.ToString (); }
 923                 public override object Evaluate (BaseIterator iter)
 924                 {
 925                         return new SlashIterator (
 926                                 new SlashIterator (
 927                                         left.EvaluateNodeSet (iter),
 928                                         DescendantOrSelfStar
 929                                 ),
 930                                 right
 931                         );
 932                 }
 933
 934                 public override bool RequireSorting { get { return left.RequireSorting || right.RequireSorting; } }
 935
 936                 internal override bool NeedAbsoluteMatching {
 937                         get { return true; }
 938                 }
 939
 940                 internal override XPathNodeType EvaluatedNodeType {
 941                         get { return right.EvaluatedNodeType; }
 942                 }
 943
 944                 internal override bool IsPositional {
 945                         get { return left.IsPositional || right.IsPositional; }
 946                 }
 947         }
 948
 949         internal class ExprRoot : NodeSet
 950         {
 951                 public override String ToString () { return ""; }
 952                 public override object Evaluate (BaseIterator iter)
 953                 {
 954                         XPathNavigator navRoot = iter.Current.Clone ();
 955                         navRoot.MoveToRoot ();
 956                         return new SelfIterator (navRoot, iter.NamespaceManager);
 957                 }
 958
 959                 internal override bool NeedAbsoluteMatching {
 960                         get { return false; }
 961                 }
 962
 963                 internal override XPathNodeType EvaluatedNodeType {
 964                         get { return XPathNodeType.Root; }
 965                 }
 966         }
 967
 968         internal enum Axes
 969         {
 970                 Ancestor,
 971                 AncestorOrSelf,
 972                 Attribute,
 973                 Child,
 974                 Descendant,
 975                 DescendantOrSelf,
 976                 Following,
 977                 FollowingSibling,
 978                 Namespace,
 979                 Parent,
 980                 Preceding,
 981                 PrecedingSibling,
 982                 Self,
 983         }
 984
 985         internal class AxisSpecifier
 986         {
 987                 protected Axes _axis;
 988                 public AxisSpecifier (Axes axis)
 989                 {
 990                         _axis = axis;
 991                 }
 992                 public XPathNodeType NodeType
 993                 {
 994                         get
 995                         {
 996                                 switch (_axis)
 997                                 {
 998                                         case Axes.Namespace:
 999                                                 return XPathNodeType.Namespace;
1000                                         case Axes.Attribute:
1001                                                 return XPathNodeType.Attribute;
1002                                         default:
1003                                                 return XPathNodeType.Element;
1004                                 }
1005                         }
1006                 }
1007                 public override string ToString ()
1008                 {
1009                         switch (_axis)
1010                         {
1011                                 case Axes.Ancestor:
1012                                         return "ancestor";
1013                                 case Axes.AncestorOrSelf:
1014                                         return "ancestor-or-self";
1015                                 case Axes.Attribute:
1016                                         return "attribute";
1017                                 case Axes.Child:
1018                                         return "child";
1019                                 case Axes.Descendant:
1020                                         return "descendant";
1021                                 case Axes.DescendantOrSelf:
1022                                         return "descendant-or-self";
1023                                 case Axes.Following:
1024                                         return "following";
1025                                 case Axes.FollowingSibling:
1026                                         return "following-sibling";
1027                                 case Axes.Namespace:
1028                                         return "namespace";
1029                                 case Axes.Parent:
1030                                         return "parent";
1031                                 case Axes.Preceding:
1032                                         return "preceeding";
1033                                 case Axes.PrecedingSibling:
1034                                         return "preceeding-sibling";
1035                                 case Axes.Self:
1036                                         return "self";
1037                                 default:
1038                                         throw new IndexOutOfRangeException ();
1039                         }
1040                 }
1041                 public Axes Axis { get { return _axis; }}
1042                 public virtual SimpleIterator Evaluate (BaseIterator iter)
1043                 {
1044                         switch (_axis)
1045                         {
1046                                 case Axes.Ancestor:
1047                                         return new AncestorIterator (iter);
1048                                 case Axes.AncestorOrSelf:
1049                                         return new AncestorOrSelfIterator (iter);
1050                                 case Axes.Attribute:
1051                                         return new AttributeIterator (iter);
1052                                 case Axes.Child:
1053                                         return new ChildIterator (iter);
1054                                 case Axes.Descendant:
1055                                         return new DescendantIterator (iter);
1056                                 case Axes.DescendantOrSelf:
1057                                         return new DescendantOrSelfIterator (iter);
1058                                 case Axes.Following:
1059                                         return new FollowingIterator (iter);
1060                                 case Axes.FollowingSibling:
1061                                         return new FollowingSiblingIterator (iter);
1062                                 case Axes.Namespace:
1063                                         return new NamespaceIterator (iter);
1064                                 case Axes.Parent:
1065                                         return new ParentIterator (iter);
1066                                 case Axes.Preceding:
1067                                         return new PrecedingIterator (iter);
1068                                 case Axes.PrecedingSibling:
1069                                         return new PrecedingSiblingIterator (iter);
1070                                 case Axes.Self:
1071                                         return new SelfIterator (iter);
1072                                 default:
1073                                         throw new IndexOutOfRangeException ();
1074                         }
1075                 }
1076         }
1077
1078         internal abstract class NodeTest : NodeSet
1079         {
1080                 protected AxisSpecifier _axis;
1081                 public NodeTest (Axes axis)
1082                 {
1083                         _axis = new AxisSpecifier (axis);
1084                 }
1085                 public abstract bool Match (XmlNamespaceManager nsm, XPathNavigator nav);
1086                 public AxisSpecifier Axis { get { return _axis; }}
1087                 public override object Evaluate (BaseIterator iter)
1088                 {
1089                         SimpleIterator iterAxis = _axis.Evaluate (iter);
1090                         return new AxisIterator (iterAxis, this);
1091                 }
1092
1093                 public abstract void GetInfo (out string name, out string ns, out XPathNodeType nodetype, XmlNamespaceManager nsm);
1094
1095                 public override bool RequireSorting {
1096                         get {
1097                                 switch (_axis.Axis) {
1098                                 case Axes.Ancestor:
1099                                 case Axes.AncestorOrSelf:
1100                                 case Axes.Preceding:
1101                                 case Axes.PrecedingSibling:
1102                                 case Axes.Namespace:
1103                                         return true;
1104                                 default:
1105                                         return false;
1106                                 }
1107                         }
1108
1109                 }
1110
1111                 internal override XPathNodeType EvaluatedNodeType {
1112                         get { return _axis.NodeType; }
1113                 }
1114         }
1115
1116         internal class NodeTypeTest : NodeTest
1117         {
1118                 public readonly XPathNodeType type;
1119                 protected String _param;
1120                 public NodeTypeTest (Axes axis) : base (axis)
1121                 {
1122                         this.type = _axis.NodeType;
1123                 }
1124                 public NodeTypeTest (Axes axis, XPathNodeType type) : base (axis)
1125                 {
1126                         this.type = type;
1127                 }
1128                 [MonoTODO]
1129                 public NodeTypeTest (Axes axis, XPathNodeType type, String param) : base (axis)
1130                 {
1131                         this.type = type;
1132                         _param = param;
1133                         if (param != null && type != XPathNodeType.ProcessingInstruction)
1134                                 throw new XPathException ("No argument allowed for "+ToString (type)+"() test");        // TODO: better description
1135                 }
1136
1137                 public override String ToString ()
1138                 {
1139                         String strType = ToString (type);
1140                         if (type == XPathNodeType.ProcessingInstruction && _param != null)
1141                                 strType += "('" + _param + "')";
1142                         else
1143                                 strType += "()";
1144
1145                         return _axis.ToString () + "::" + strType;
1146                 }
1147
1148                 private static String ToString (XPathNodeType type)
1149                 {
1150                         switch (type)
1151                         {
1152                                 case XPathNodeType.Comment:
1153                                         return "comment";
1154                                 case XPathNodeType.Text:
1155                                         return "text";
1156                                 case XPathNodeType.ProcessingInstruction:
1157                                         return "processing-instruction";
1158                                 case XPathNodeType.All:
1159                                 case XPathNodeType.Attribute:
1160                                 case XPathNodeType.Element:
1161                                 case XPathNodeType.Namespace:
1162                                         return "node";
1163                                 default:
1164                                         return "node-type [" + type.ToString () + "]";
1165                         }
1166                 }
1167
1168                 public override bool Match (XmlNamespaceManager nsm, XPathNavigator nav)
1169                 {
1170                         XPathNodeType nodeType = nav.NodeType;
1171                         switch (type)
1172                         {
1173                                 case XPathNodeType.All:
1174                                         return true;
1175
1176                                 case XPathNodeType.ProcessingInstruction:
1177                                         if (nodeType != XPathNodeType.ProcessingInstruction)
1178                                                 return false;
1179                                         if (_param != null && nav.Name != _param)
1180                                                 return false;
1181                                         return true;
1182
1183                                 default:
1184                                         return type == nodeType;
1185                         }
1186                 }
1187
1188                 public override void GetInfo (out string name, out string ns, out XPathNodeType nodetype, XmlNamespaceManager nsm)
1189                 {
1190                         name = _param;
1191                         ns = null;
1192                         nodetype = type;
1193                 }
1194         }
1195
1196         internal class NodeNameTest : NodeTest
1197         {
1198                 protected XmlQualifiedName _name;
1199                 protected readonly bool resolvedName = false;
1200                 public NodeNameTest (Axes axis, XmlQualifiedName name, IStaticXsltContext ctx) : base (axis)
1201                 {
1202                         if (ctx != null) {
1203                                 name = ctx.LookupQName (name.ToString ());
1204                                 resolvedName = true;
1205                         }
1206                         _name = name;
1207                 }
1208
1209                 public NodeNameTest (Axes axis, XmlQualifiedName name, bool resolvedName) : base (axis)
1210                 {
1211                         _name = name;
1212                         resolvedName = resolvedName;
1213                 }
1214                 public override String ToString () { return _axis.ToString () + "::" + _name.ToString (); }
1215
1216                 public XmlQualifiedName Name { get { return _name; } }
1217                 [MonoTODO]
1218                 public override bool Match (XmlNamespaceManager nsm, XPathNavigator nav)
1219                 {
1220                         // must be the correct node type
1221                         if (nav.NodeType != _axis.NodeType)
1222                                 return false;
1223
1224                         if (_name.Name != "")
1225                         {
1226                                 // test the local part of the name first
1227                                 if (_name.Name != nav.LocalName)
1228                                         return false;
1229                         }
1230
1231                         // get the prefix for the given name
1232                         String strURI1 = "";
1233                         if (nsm != null && _name.Namespace != "")
1234                         {
1235                                 if (resolvedName)
1236                                         strURI1 = _name.Namespace;
1237                                 else
1238                                         strURI1 = nsm.LookupNamespace (_name.Namespace);        // TODO: check to see if this returns null or ""
1239                                 if (strURI1 == null)
1240                                         throw new XPathException ("Invalid namespace prefix: "+_name.Namespace);
1241                         }
1242
1243                         string strURI = nav.NamespaceURI;
1244                         if (strURI == null && strURI1 == "")    // TODO: remove when bug #26855 fixed
1245                                 return true;
1246
1247                         // test the prefixes
1248                         return strURI1 == nav.NamespaceURI;
1249                 }
1250
1251                 public override void GetInfo (out string name, out string ns, out XPathNodeType nodetype, XmlNamespaceManager nsm)
1252                 {
1253                         // must be the correct node type
1254                         nodetype = _axis.NodeType;
1255
1256                         if (_name.Name != "")
1257                                 name = _name.Name;
1258                         else
1259                                 name = null;
1260                         ns = "";
1261                         if (nsm != null && _name.Namespace != "") {
1262                                 if (resolvedName)
1263                                         ns = _name.Namespace;
1264                                 else
1265                                         ns = nsm.LookupNamespace (_name.Namespace);     // TODO: check to see if this returns null or ""
1266                                 if (ns == null)
1267                                         throw new XPathException ("Invalid namespace prefix: "+_name.Namespace);
1268                         }
1269                 }
1270         }
1271
1272         internal class ExprFilter : NodeSet
1273         {
1274                 public readonly Expression expr, pred;
1275
1276                 public ExprFilter (Expression expr, Expression pred)
1277                 {
1278                         this.expr = expr;
1279                         this.pred = pred;
1280                 }
1281
1282                 internal Expression LeftHandSide {get{return expr;}}
1283                 public override String ToString () { return "(" + expr.ToString () + ")[" + pred.ToString () + "]"; }
1284                 public override object Evaluate (BaseIterator iter)
1285                 {
1286                         BaseIterator iterExpr = expr.EvaluateNodeSet (iter);
1287                         return new PredicateIterator (iterExpr, pred);
1288                 }
1289
1290                 internal override bool NeedAbsoluteMatching {
1291                         get { return expr.NeedAbsoluteMatching; }
1292                 }
1293
1294                 internal override XPathNodeType EvaluatedNodeType {
1295                         get { return expr.EvaluatedNodeType; }
1296                 }
1297
1298                 internal override bool IsPositional {
1299                         get {
1300                                 if (pred.ReturnType == XPathResultType.Number)
1301                                         return true;
1302                                 return expr.IsPositional || pred.IsPositional;
1303                         }
1304                 }
1305         }
1306
1307         internal class ExprNumber : Expression
1308         {
1309                 protected double _value;
1310                 public ExprNumber (double value)
1311                 {
1312                         _value = value;
1313                 }
1314                 public override String ToString () { return _value.ToString (); }
1315                 public override XPathResultType ReturnType { get { return XPathResultType.Number; }}
1316                 public override object Evaluate (BaseIterator iter)
1317                 {
1318                         return _value;
1319                 }
1320
1321                 public override double EvaluateNumber (BaseIterator iter)
1322                 {
1323                         return _value;
1324                 }
1325
1326                 internal override bool IsPositional {
1327                         get { return false; }
1328                 }
1329         }
1330
1331         internal class ExprLiteral : Expression
1332         {
1333                 protected String _value;
1334                 public ExprLiteral (String value)
1335                 {
1336                         _value = value;
1337                 }
1338                 public string Value { get { return _value; } }
1339                 public override String ToString () { return "'" + _value + "'"; }
1340                 public override XPathResultType ReturnType { get { return XPathResultType.String; }}
1341                 public override object Evaluate (BaseIterator iter)
1342                 {
1343                         return _value;
1344                 }
1345
1346                 public override string EvaluateString (BaseIterator iter)
1347                 {
1348                         return _value;
1349                 }
1350         }
1351
1352         internal class ExprVariable : Expression
1353         {
1354                 protected XmlQualifiedName _name;
1355                 protected bool resolvedName = false;
1356                 public ExprVariable (XmlQualifiedName name, IStaticXsltContext ctx)
1357                 {
1358                         if (ctx != null) {
1359                                 name = ctx.LookupQName (name.ToString ());
1360                                 resolvedName = true;
1361                         }
1362
1363                         _name = name;
1364                 }
1365                 public override String ToString () { return "$" + _name.ToString (); }
1366                 public override XPathResultType ReturnType { get { return XPathResultType.Any; }}
1367                 public override XPathResultType GetReturnType (BaseIterator iter)
1368                 {
1369                         return XPathResultType.Any;
1370                 }
1371
1372                 public override object Evaluate (BaseIterator iter)
1373                 {
1374                         IXsltContextVariable var = null;
1375
1376                         XsltContext context = iter.NamespaceManager as XsltContext;
1377                         if (context != null) {
1378                                 if (resolvedName)
1379                                         var = context.ResolveVariable (_name);
1380                                 else
1381                                         var = context.ResolveVariable (_name.Namespace, _name.Name);
1382                         }
1383
1384                         if (var == null)
1385                                 throw new XPathException ("variable "+_name.ToString ()+" not found");
1386                         object objResult = var.Evaluate (context);
1387                         XPathNodeIterator iterResult = objResult as XPathNodeIterator;
1388                         if (iterResult != null)
1389                                 return iterResult.Clone ();
1390                         return objResult;
1391                 }
1392         }
1393
1394         internal class ExprParens : Expression
1395         {
1396                 protected Expression _expr;
1397                 public ExprParens (Expression expr)
1398                 {
1399                         _expr = expr;
1400                 }
1401                 public override String ToString () { return "(" + _expr.ToString () + ")"; }
1402                 public override XPathResultType ReturnType { get { return _expr.ReturnType; }}
1403                 public override object Evaluate (BaseIterator iter)
1404                 {
1405                         object o = (_expr.Evaluate (iter));
1406                         BaseIterator predBase = o as BaseIterator;
1407                         if (predBase != null)
1408                                 return new ParensIterator (predBase);
1409                         else
1410                                 return o;
1411                 }
1412
1413                 internal override bool NeedAbsoluteMatching {
1414                         get { return _expr.NeedAbsoluteMatching; }
1415                 }
1416
1417                 internal override XPathNodeType EvaluatedNodeType {
1418                         get { return _expr.EvaluatedNodeType; }
1419                 }
1420
1421                 internal override bool IsPositional {
1422                         get { return _expr.IsPositional; }
1423                 }
1424         }
1425
1426         internal class FunctionArguments
1427         {
1428                 protected Expression _arg;
1429                 protected FunctionArguments _tail;
1430                 public FunctionArguments (Expression arg, FunctionArguments tail)
1431                 {
1432                         _arg = arg;
1433                         _tail = tail;
1434                 }
1435                 public Expression Arg
1436                 {
1437                         get { return _arg; }
1438                 }
1439                 public FunctionArguments Tail
1440                 {
1441                         get { return _tail; }
1442                 }
1443
1444                 public void ToArrayList (ArrayList a)
1445                 {
1446                         FunctionArguments cur = this;
1447
1448                         do {
1449                                 a.Add (cur._arg);
1450                                 cur = cur._tail;
1451                         } while (cur != null);
1452
1453                 }
1454         }
1455
1456         internal class ExprFunctionCall : Expression
1457         {
1458                 protected readonly XmlQualifiedName _name;
1459                 protected readonly bool resolvedName = false;
1460                 protected readonly ArrayList _args = new ArrayList ();
1461                 public ExprFunctionCall (XmlQualifiedName name, FunctionArguments args, IStaticXsltContext ctx)
1462                 {
1463                         if (ctx != null) {
1464                                 name = ctx.LookupQName (name.ToString ());
1465                                 resolvedName = true;
1466                         }
1467
1468                         _name = name;
1469                         if (args != null)
1470                                 args.ToArrayList (_args);
1471                 }
1472
1473                 public static Expression Factory (XmlQualifiedName name, FunctionArguments args, IStaticXsltContext ctx)
1474                 {
1475                         if (name.Namespace != null && name.Namespace != "")
1476                                 return new ExprFunctionCall (name, args, ctx);
1477
1478                         switch (name.Name) {
1479                                 case "last": return new XPathFunctionLast (args);
1480                                 case "position": return new XPathFunctionPosition (args);
1481                                 case "count": return new XPathFunctionCount (args);
1482                                 case "id": return new XPathFunctionId (args);
1483                                 case "local-name": return new XPathFunctionLocalName (args);
1484                                 case "namespace-uri": return new XPathFunctionNamespaceUri (args);
1485                                 case "name": return new XPathFunctionName (args);
1486                                 case "string": return new XPathFunctionString (args);
1487                                 case "concat": return new XPathFunctionConcat (args);
1488                                 case "starts-with": return new XPathFunctionStartsWith (args);
1489                                 case "contains": return new XPathFunctionContains (args);
1490                                 case "substring-before": return new XPathFunctionSubstringBefore (args);
1491                                 case "substring-after": return new XPathFunctionSubstringAfter (args);
1492                                 case "substring": return new XPathFunctionSubstring (args);
1493                                 case "string-length": return new XPathFunctionStringLength (args);
1494                                 case "normalize-space": return new XPathFunctionNormalizeSpace (args);
1495                                 case "translate": return new XPathFunctionTranslate (args);
1496                                 case "boolean": return new XPathFunctionBoolean (args);
1497                                 case "not": return new XPathFunctionNot (args);
1498                                 case "true": return new XPathFunctionTrue (args);
1499                                 case "false": return new XPathFunctionFalse (args);
1500                                 case "lang": return new XPathFunctionLang (args);
1501                                 case "number": return new XPathFunctionNumber (args);
1502                                 case "sum": return new XPathFunctionSum (args);
1503                                 case "floor": return new XPathFunctionFloor (args);
1504                                 case "ceiling": return new XPathFunctionCeil (args);
1505                                 case "round": return new XPathFunctionRound (args);
1506                         }
1507                         return new ExprFunctionCall (name, args, ctx);
1508                 }
1509
1510                 public override String ToString ()
1511                 {
1512                         String strArgs = "";
1513                         for (int i = 0; i < _args.Count; i++) {
1514                                 Expression arg = (Expression) _args [i];
1515                                 if (strArgs != "")
1516                                         strArgs += ", ";
1517                                 strArgs += arg.ToString ();
1518                         }
1519                         return _name.ToString () + '(' + strArgs + ')';
1520                 }
1521                 public override XPathResultType ReturnType { get { return XPathResultType.Any; }}
1522                 public override XPathResultType GetReturnType (BaseIterator iter)
1523                 {
1524                         return XPathResultType.Any;
1525                 }
1526
1527                 private XPathResultType [] GetArgTypes (BaseIterator iter)
1528                 {
1529                         // TODO: can we cache these? what if the types depend on the nsm?
1530                         XPathResultType [] rgArgs = new XPathResultType [_args.Count];
1531                         for (int iArg = 0; iArg < _args.Count; iArg++)
1532                                 rgArgs [iArg] = ((Expression) _args [iArg]).GetReturnType (iter);
1533                         return rgArgs;
1534                 }
1535                 public override object Evaluate (BaseIterator iter)
1536                 {
1537                         XPathResultType [] rgTypes = GetArgTypes (iter);
1538                         IXsltContextFunction func = null;
1539                         XsltContext context = iter.NamespaceManager as XsltContext;
1540                         if (context != null) {
1541                                 if (resolvedName)
1542                                         func = context.ResolveFunction (_name, rgTypes);
1543                                 else
1544                                         func = context.ResolveFunction (_name.Namespace, _name.Name, rgTypes);
1545                         }
1546
1547                         if (func == null)
1548                                 throw new XPathException ("function "+_name.ToString ()+" not found");
1549
1550                         object [] rgArgs = new object [_args.Count];
1551                         if (func.Maxargs != 0)
1552                         {
1553                                 XPathResultType [] rgFuncTypes = func.ArgTypes;
1554                                 for (int iArg = 0; iArg < _args.Count; iArg ++)
1555                                 {
1556                                         XPathResultType typeArg;
1557                                         if (rgFuncTypes == null)
1558                                                 typeArg = XPathResultType.Any;
1559                                         else if (iArg < rgFuncTypes.Length)
1560                                                 typeArg = rgFuncTypes [iArg];
1561                                         else
1562                                                 typeArg = rgFuncTypes [rgFuncTypes.Length - 1];
1563
1564                                         Expression arg = (Expression) _args [iArg];
1565                                         object result = arg.EvaluateAs (iter, typeArg);
1566                                         rgArgs [iArg] = result;
1567                                 }
1568                         }
1569                         return func.Invoke (context, rgArgs, iter.Current);
1570                 }
1571         }
1572 }