mcs/mcs/eval.cs

   1 //
   2 // eval.cs: Evaluation and Hosting API for the C# compiler
   3 //
   4 // Authors:
   5 //   Miguel de Icaza (miguel@gnome.org)
   6 //   Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Dual licensed under the terms of the MIT X11 or GNU GPL
   9 //
  10 // Copyright 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
  11 // Copyright 2004-2011 Novell, Inc
  12 //
  13
  14 using System;
  15 using System.Threading;
  16 using System.Collections.Generic;
  17 using System.Reflection;
  18 using System.Reflection.Emit;
  19 using System.IO;
  20 using System.Text;
  21 using System.Linq;
  22
  23 namespace Mono.CSharp
  24 {
  25
  26         /// <summary>
  27         ///   Evaluator: provides an API to evaluate C# statements and
  28         ///   expressions dynamically.
  29         /// </summary>
  30         /// <remarks>
  31         ///   This class exposes static methods to evaluate expressions in the
  32         ///   current program.
  33         ///
  34         ///   To initialize the evaluator with a number of compiler
  35         ///   options call the Init(string[]args) method with a set of
  36         ///   command line options that the compiler recognizes.
  37         ///
  38         ///   To interrupt execution of a statement, you can invoke the
  39         ///   Evaluator.Interrupt method.
  40         /// </remarks>
  41         public class Evaluator {
  42
  43                 enum ParseMode {
  44                         // Parse silently, do not output any error messages
  45                         Silent,
  46
  47                         // Report errors during parse
  48                         ReportErrors,
  49
  50                         // Auto-complete, means that the tokenizer will start producing
  51                         // GETCOMPLETIONS tokens when it reaches a certain point.
  52                         GetCompletions
  53                 }
  54
  55                 static object evaluator_lock = new object ();
  56                 static volatile bool invoking;
  57
  58                 static int count;
  59                 static Thread invoke_thread;
  60
  61                 readonly Dictionary<string, Tuple<FieldSpec, FieldInfo>> fields;
  62
  63                 Type base_class;
  64                 bool inited;
  65                 int startup_files;
  66
  67                 readonly CompilerContext ctx;
  68                 readonly ModuleContainer module;
  69                 readonly ReflectionImporter importer;
  70                 readonly CompilationSourceFile source_file;
  71
  72                 public Evaluator (CompilerSettings settings, Report report)
  73                 {
  74                         ctx = new CompilerContext (settings, report);
  75
  76                         module = new ModuleContainer (ctx);
  77                         module.Evaluator = this;
  78
  79                         source_file = new CompilationSourceFile ("{interactive}", "", 1);
  80                         source_file.NamespaceContainer = new NamespaceContainer (null, module, null, source_file);
  81
  82                         startup_files = ctx.SourceFiles.Count;
  83                         ctx.SourceFiles.Add (source_file);
  84
  85                         // FIXME: Importer needs this assembly for internalsvisibleto
  86                         module.SetDeclaringAssembly (new AssemblyDefinitionDynamic (module, "evaluator"));
  87                         importer = new ReflectionImporter (module, ctx.BuiltinTypes);
  88
  89                         InteractiveBaseClass = typeof (InteractiveBase);
  90                         fields = new Dictionary<string, Tuple<FieldSpec, FieldInfo>> ();
  91                 }
  92
  93                 void Init ()
  94                 {
  95                         var loader = new DynamicLoader (importer, ctx);
  96
  97                         CompilerCallableEntryPoint.Reset ();
  98                         RootContext.ToplevelTypes = module;
  99
 100                         //var startup_files = new List<string> ();
 101                         //foreach (CompilationUnit file in Location.SourceFiles)
 102                         //    startup_files.Add (file.Path);
 103
 104                         loader.LoadReferences (module);
 105                         ctx.BuiltinTypes.CheckDefinitions (module);
 106                         module.InitializePredefinedTypes ();
 107
 108                         inited = true;
 109                 }
 110
 111                 void ParseStartupFiles ()
 112                 {
 113                         Driver d = new Driver (ctx);
 114
 115                         Location.Initialize (ctx.SourceFiles);
 116
 117                         for (int i = 0; i < startup_files; ++i) {
 118                                 var sf = ctx.Settings.SourceFiles [i];
 119                                 d.Parse (sf, module);
 120                         }
 121                 }
 122
 123                 void Reset ()
 124                 {
 125                         CompilerCallableEntryPoint.PartialReset ();
 126
 127                         Location.Reset ();
 128                         Location.Initialize (ctx.SourceFiles);
 129                 }
 130
 131                 /// <summary>
 132                 ///   If true, turns type expressions into valid expressions
 133                 ///   and calls the describe method on it
 134                 /// </summary>
 135                 public bool DescribeTypeExpressions;
 136
 137                 /// <summary>
 138                 ///   The base class for the classes that host the user generated code
 139                 /// </summary>
 140                 /// <remarks>
 141                 ///
 142                 ///   This is the base class that will host the code
 143                 ///   executed by the Evaluator.  By default
 144                 ///   this is the Mono.CSharp.InteractiveBase class
 145                 ///   which is useful for interactive use.
 146                 ///
 147                 ///   By changing this property you can control the
 148                 ///   base class and the static members that are
 149                 ///   available to your evaluated code.
 150                 /// </remarks>
 151                 public Type InteractiveBaseClass {
 152                         get {
 153                                 return base_class;
 154                         }
 155                         set {
 156                                 base_class = value;
 157
 158                                 if (value != null && typeof (InteractiveBase).IsAssignableFrom (value))
 159                                         InteractiveBase.Evaluator = this;
 160                         }
 161                 }
 162
 163                 /// <summary>
 164                 ///   Interrupts the evaluation of an expression executing in Evaluate.
 165                 /// </summary>
 166                 /// <remarks>
 167                 ///   Use this method to interrupt long-running invocations.
 168                 /// </remarks>
 169                 public void Interrupt ()
 170                 {
 171                         if (!inited || !invoking)
 172                                 return;
 173
 174                         if (invoke_thread != null)
 175                                 invoke_thread.Abort ();
 176                 }
 177
 178                 /// <summary>
 179                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 180                 /// </summary>
 181                 /// <remarks>
 182                 ///
 183                 ///   Compiles the input string as a C# expression or
 184                 ///   statement, unlike the Evaluate method, the
 185                 ///   resulting delegate can be invoked multiple times
 186                 ///   without incurring in the compilation overhead.
 187                 ///
 188                 ///   If the return value of this function is null,
 189                 ///   this indicates that the parsing was complete.
 190                 ///   If the return value is a string it indicates
 191                 ///   that the input string was partial and that the
 192                 ///   invoking code should provide more code before
 193                 ///   the code can be successfully compiled.
 194                 ///
 195                 ///   If you know that you will always get full expressions or
 196                 ///   statements and do not care about partial input, you can use
 197                 ///   the other Compile overload.
 198                 ///
 199                 ///   On success, in addition to returning null, the
 200                 ///   compiled parameter will be set to the delegate
 201                 ///   that can be invoked to execute the code.
 202                 ///
 203             /// </remarks>
 204                 public string Compile (string input, out CompiledMethod compiled)
 205                 {
 206                         if (input == null || input.Length == 0){
 207                                 compiled = null;
 208                                 return null;
 209                         }
 210
 211                         lock (evaluator_lock){
 212                                 if (!inited) {
 213                                         Init ();
 214                                         ParseStartupFiles ();
 215                                 } else {
 216                                         ctx.Report.Printer.Reset ();
 217                                 }
 218
 219                                 bool partial_input;
 220                                 CSharpParser parser = ParseString (ParseMode.Silent, input, out partial_input);
 221                                 if (parser == null){
 222                                         compiled = null;
 223                                         if (partial_input)
 224                                                 return input;
 225
 226                                         ParseString (ParseMode.ReportErrors, input, out partial_input);
 227                                         return null;
 228                                 }
 229
 230                                 Class parser_result = parser.InteractiveResult;
 231                                 compiled = CompileBlock (parser_result, parser.undo, ctx.Report);
 232                                 return null;
 233                         }
 234                 }
 235
 236                 /// <summary>
 237                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 238                 /// </summary>
 239                 /// <remarks>
 240                 ///
 241                 ///   Compiles the input string as a C# expression or
 242                 ///   statement, unlike the Evaluate method, the
 243                 ///   resulting delegate can be invoked multiple times
 244                 ///   without incurring in the compilation overhead.
 245                 ///
 246                 ///   This method can only deal with fully formed input
 247                 ///   strings and does not provide a completion mechanism.
 248                 ///   If you must deal with partial input (for example for
 249                 ///   interactive use) use the other overload.
 250                 ///
 251                 ///   On success, a delegate is returned that can be used
 252                 ///   to invoke the method.
 253                 ///
 254                 /// </remarks>
 255                 public CompiledMethod Compile (string input)
 256                 {
 257                         CompiledMethod compiled;
 258
 259                         // Ignore partial inputs
 260                         if (Compile (input, out compiled) != null){
 261                                 // Error, the input was partial.
 262                                 return null;
 263                         }
 264
 265                         // Either null (on error) or the compiled method.
 266                         return compiled;
 267                 }
 268
 269                 /// <summary>
 270                 ///   Evaluates and expression or statement and returns any result values.
 271                 /// </summary>
 272                 /// <remarks>
 273                 ///   Evaluates the input string as a C# expression or
 274                 ///   statement.  If the input string is an expression
 275                 ///   the result will be stored in the result variable
 276                 ///   and the result_set variable will be set to true.
 277                 ///
 278                 ///   It is necessary to use the result/result_set
 279                 ///   pair to identify when a result was set (for
 280                 ///   example, execution of user-provided input can be
 281                 ///   an expression, a statement or others, and
 282                 ///   result_set would only be set if the input was an
 283                 ///   expression.
 284                 ///
 285                 ///   If the return value of this function is null,
 286                 ///   this indicates that the parsing was complete.
 287                 ///   If the return value is a string, it indicates
 288                 ///   that the input is partial and that the user
 289                 ///   should provide an updated string.
 290                 /// </remarks>
 291                 public string Evaluate (string input, out object result, out bool result_set)
 292                 {
 293                         CompiledMethod compiled;
 294
 295                         result_set = false;
 296                         result = null;
 297
 298                         input = Compile (input, out compiled);
 299                         if (input != null)
 300                                 return input;
 301
 302                         if (compiled == null)
 303                                 return null;
 304
 305                         //
 306                         // The code execution does not need to keep the compiler lock
 307                         //
 308                         object retval = typeof (QuitValue);
 309
 310                         try {
 311                                 invoke_thread = System.Threading.Thread.CurrentThread;
 312                                 invoking = true;
 313                                 compiled (ref retval);
 314                         } catch (ThreadAbortException e){
 315                                 Thread.ResetAbort ();
 316                                 Console.WriteLine ("Interrupted!\n{0}", e);
 317                         } finally {
 318                                 invoking = false;
 319                         }
 320
 321                         //
 322                         // We use a reference to a compiler type, in this case
 323                         // Driver as a flag to indicate that this was a statement
 324                         //
 325                         if (!ReferenceEquals (retval, typeof (QuitValue))) {
 326                                 result_set = true;
 327                                 result = retval;
 328                         }
 329
 330                         return null;
 331                 }
 332
 333                 public string [] GetCompletions (string input, out string prefix)
 334                 {
 335                         prefix = "";
 336                         if (input == null || input.Length == 0)
 337                                 return null;
 338
 339                         lock (evaluator_lock){
 340                                 if (!inited)
 341                                         Init ();
 342
 343                                 bool partial_input;
 344                                 CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
 345                                 if (parser == null){
 346                                         if (CSharpParser.yacc_verbose_flag != 0)
 347                                                 Console.WriteLine ("DEBUG: No completions available");
 348                                         return null;
 349                                 }
 350
 351                                 Class parser_result = parser.InteractiveResult;
 352
 353 #if NET_4_0
 354                                 var access = AssemblyBuilderAccess.RunAndCollect;
 355 #else
 356                                 var access = AssemblyBuilderAccess.Run;
 357 #endif
 358                                 var a = new AssemblyDefinitionDynamic (module, "completions");
 359                                 a.Create (AppDomain.CurrentDomain, access);
 360                                 module.SetDeclaringAssembly (a);
 361
 362                                 // Need to setup MemberCache
 363                                 parser_result.CreateType ();
 364
 365                                 var method = parser_result.Methods[0] as Method;
 366                                 BlockContext bc = new BlockContext (method, method.Block, ctx.BuiltinTypes.Void);
 367
 368                                 try {
 369                                         method.Block.Resolve (null, bc, method);
 370                                 } catch (CompletionResult cr) {
 371                                         prefix = cr.BaseText;
 372                                         return cr.Result;
 373                                 }
 374                         }
 375                         return null;
 376                 }
 377
 378                 /// <summary>
 379                 ///   Executes the given expression or statement.
 380                 /// </summary>
 381                 /// <remarks>
 382                 ///    Executes the provided statement, returns true
 383                 ///    on success, false on parsing errors.  Exceptions
 384                 ///    might be thrown by the called code.
 385                 /// </remarks>
 386                 public bool Run (string statement)
 387                 {
 388                         object result;
 389                         bool result_set;
 390
 391                         return Evaluate (statement, out result, out result_set) == null;
 392                 }
 393
 394                 /// <summary>
 395                 ///   Evaluates and expression or statement and returns the result.
 396                 /// </summary>
 397                 /// <remarks>
 398                 ///   Evaluates the input string as a C# expression or
 399                 ///   statement and returns the value.
 400                 ///
 401                 ///   This method will throw an exception if there is a syntax error,
 402                 ///   of if the provided input is not an expression but a statement.
 403                 /// </remarks>
 404                 public object Evaluate (string input)
 405                 {
 406                         object result;
 407                         bool result_set;
 408
 409                         string r = Evaluate (input, out result, out result_set);
 410
 411                         if (r != null)
 412                                 throw new ArgumentException ("Syntax error on input: partial input");
 413
 414                         if (result_set == false)
 415                                 throw new ArgumentException ("The expression did not set a result");
 416
 417                         return result;
 418                 }
 419
 420                 enum InputKind {
 421                         EOF,
 422                         StatementOrExpression,
 423                         CompilationUnit,
 424                         Error
 425                 }
 426
 427                 //
 428                 // Deambiguates the input string to determine if we
 429                 // want to process a statement or if we want to
 430                 // process a compilation unit.
 431                 //
 432                 // This is done using a top-down predictive parser,
 433                 // since the yacc/jay parser can not deambiguage this
 434                 // without more than one lookahead token.   There are very
 435                 // few ambiguities.
 436                 //
 437                 InputKind ToplevelOrStatement (SeekableStreamReader seekable)
 438                 {
 439                         Tokenizer tokenizer = new Tokenizer (seekable, source_file, ctx);
 440
 441                         int t = tokenizer.token ();
 442                         switch (t){
 443                         case Token.EOF:
 444                                 return InputKind.EOF;
 445
 446                         // These are toplevels
 447                         case Token.EXTERN:
 448                         case Token.OPEN_BRACKET:
 449                         case Token.ABSTRACT:
 450                         case Token.CLASS:
 451                         case Token.ENUM:
 452                         case Token.INTERFACE:
 453                         case Token.INTERNAL:
 454                         case Token.NAMESPACE:
 455                         case Token.PRIVATE:
 456                         case Token.PROTECTED:
 457                         case Token.PUBLIC:
 458                         case Token.SEALED:
 459                         case Token.STATIC:
 460                         case Token.STRUCT:
 461                                 return InputKind.CompilationUnit;
 462
 463                         // Definitely expression
 464                         case Token.FIXED:
 465                         case Token.BOOL:
 466                         case Token.BYTE:
 467                         case Token.CHAR:
 468                         case Token.DECIMAL:
 469                         case Token.DOUBLE:
 470                         case Token.FLOAT:
 471                         case Token.INT:
 472                         case Token.LONG:
 473                         case Token.NEW:
 474                         case Token.OBJECT:
 475                         case Token.SBYTE:
 476                         case Token.SHORT:
 477                         case Token.STRING:
 478                         case Token.UINT:
 479                         case Token.ULONG:
 480                                 return InputKind.StatementOrExpression;
 481
 482                         // These need deambiguation help
 483                         case Token.USING:
 484                                 t = tokenizer.token ();
 485                                 if (t == Token.EOF)
 486                                         return InputKind.EOF;
 487
 488                                 if (t == Token.IDENTIFIER)
 489                                         return InputKind.CompilationUnit;
 490                                 return InputKind.StatementOrExpression;
 491
 492
 493                         // Distinguish between:
 494                         //    delegate opt_anonymous_method_signature block
 495                         //    delegate type
 496                         case Token.DELEGATE:
 497                                 t = tokenizer.token ();
 498                                 if (t == Token.EOF)
 499                                         return InputKind.EOF;
 500                                 if (t == Token.OPEN_PARENS || t == Token.OPEN_BRACE)
 501                                         return InputKind.StatementOrExpression;
 502                                 return InputKind.CompilationUnit;
 503
 504                         // Distinguih between:
 505                         //    unsafe block
 506                         //    unsafe as modifier of a type declaration
 507                         case Token.UNSAFE:
 508                                 t = tokenizer.token ();
 509                                 if (t == Token.EOF)
 510                                         return InputKind.EOF;
 511                                 if (t == Token.OPEN_PARENS)
 512                                         return InputKind.StatementOrExpression;
 513                                 return InputKind.CompilationUnit;
 514
 515                         // These are errors: we list explicitly what we had
 516                         // from the grammar, ERROR and then everything else
 517
 518                         case Token.READONLY:
 519                         case Token.OVERRIDE:
 520                         case Token.ERROR:
 521                                 return InputKind.Error;
 522
 523                         // This catches everything else allowed by
 524                         // expressions.  We could add one-by-one use cases
 525                         // if needed.
 526                         default:
 527                                 return InputKind.StatementOrExpression;
 528                         }
 529                 }
 530
 531                 //
 532                 // Parses the string @input and returns a CSharpParser if succeeful.
 533                 //
 534                 // if @silent is set to true then no errors are
 535                 // reported to the user.  This is used to do various calls to the
 536                 // parser and check if the expression is parsable.
 537                 //
 538                 // @partial_input: if @silent is true, then it returns whether the
 539                 // parsed expression was partial, and more data is needed
 540                 //
 541                 CSharpParser ParseString (ParseMode mode, string input, out bool partial_input)
 542                 {
 543                         partial_input = false;
 544                         Reset ();
 545                         Tokenizer.LocatedToken.Initialize ();
 546
 547                         var enc = ctx.Settings.Encoding;
 548                         var s = new MemoryStream (enc.GetBytes (input));
 549                         SeekableStreamReader seekable = new SeekableStreamReader (s, enc);
 550
 551                         InputKind kind = ToplevelOrStatement (seekable);
 552                         if (kind == InputKind.Error){
 553                                 if (mode == ParseMode.ReportErrors)
 554                                         ctx.Report.Error (-25, "Detection Parsing Error");
 555                                 partial_input = false;
 556                                 return null;
 557                         }
 558
 559                         if (kind == InputKind.EOF){
 560                                 if (mode == ParseMode.ReportErrors)
 561                                         Console.Error.WriteLine ("Internal error: EOF condition should have been detected in a previous call with silent=true");
 562                                 partial_input = true;
 563                                 return null;
 564
 565                         }
 566                         seekable.Position = 0;
 567
 568                         source_file.NamespaceContainer.DeclarationFound = false;
 569                         CSharpParser parser = new CSharpParser (seekable, source_file);
 570
 571                         if (kind == InputKind.StatementOrExpression){
 572                                 parser.Lexer.putback_char = Tokenizer.EvalStatementParserCharacter;
 573                                 ctx.Settings.StatementMode = true;
 574                         } else {
 575                                 parser.Lexer.putback_char = Tokenizer.EvalCompilationUnitParserCharacter;
 576                                 ctx.Settings.StatementMode = false;
 577                         }
 578
 579                         if (mode == ParseMode.GetCompletions)
 580                                 parser.Lexer.CompleteOnEOF = true;
 581
 582                         ReportPrinter old_printer = null;
 583                         if ((mode == ParseMode.Silent || mode == ParseMode.GetCompletions) && CSharpParser.yacc_verbose_flag == 0)
 584                                 old_printer = ctx.Report.SetPrinter (new StreamReportPrinter (TextWriter.Null));
 585
 586                         try {
 587                                 parser.parse ();
 588                         } finally {
 589                                 if (ctx.Report.Errors != 0){
 590                                         if (mode != ParseMode.ReportErrors  && parser.UnexpectedEOF)
 591                                                 partial_input = true;
 592
 593                                         if (parser.undo != null)
 594                                                 parser.undo.ExecuteUndo ();
 595
 596                                         parser = null;
 597                                 }
 598
 599                                 if (old_printer != null)
 600                                         ctx.Report.SetPrinter (old_printer);
 601                         }
 602                         return parser;
 603                 }
 604
 605                 CompiledMethod CompileBlock (Class host, Undo undo, Report Report)
 606                 {
 607                         string current_debug_name = "eval-" + count + ".dll";
 608                         ++count;
 609 #if STATIC
 610                         throw new NotSupportedException ();
 611 #else
 612                         AssemblyDefinitionDynamic assembly;
 613                         AssemblyBuilderAccess access;
 614
 615                         if (Environment.GetEnvironmentVariable ("SAVE") != null) {
 616                                 access = AssemblyBuilderAccess.RunAndSave;
 617                                 assembly = new AssemblyDefinitionDynamic (module, current_debug_name, current_debug_name);
 618                                 assembly.Importer = importer;
 619                         } else {
 620 #if NET_4_0
 621                                 access = AssemblyBuilderAccess.RunAndCollect;
 622 #else
 623                                 access = AssemblyBuilderAccess.Run;
 624 #endif
 625                                 assembly = new AssemblyDefinitionDynamic (module, current_debug_name);
 626                         }
 627
 628                         assembly.Create (AppDomain.CurrentDomain, access);
 629
 630                         Method expression_method;
 631                         if (host != null) {
 632                                 var base_class_imported = importer.ImportType (base_class);
 633                                 var baseclass_list = new List<FullNamedExpression> (1) {
 634                                         new TypeExpression (base_class_imported, host.Location)
 635                                 };
 636
 637                                 host.AddBasesForPart (host, baseclass_list);
 638
 639                                 host.CreateType ();
 640                                 host.DefineType ();
 641                                 host.Define ();
 642
 643                                 expression_method = (Method) host.Methods[0];
 644                         } else {
 645                                 expression_method = null;
 646                         }
 647
 648                         module.CreateType ();
 649                         module.Define ();
 650
 651                         if (Report.Errors != 0){
 652                                 if (undo != null)
 653                                         undo.ExecuteUndo ();
 654
 655                                 return null;
 656                         }
 657
 658                         if (host != null){
 659                                 host.EmitType ();
 660                         }
 661
 662                         module.Emit ();
 663                         if (Report.Errors != 0){
 664                                 if (undo != null)
 665                                         undo.ExecuteUndo ();
 666                                 return null;
 667                         }
 668
 669                         module.CloseType ();
 670                         if (host != null)
 671                                 host.CloseType ();
 672
 673                         if (access == AssemblyBuilderAccess.RunAndSave)
 674                                 assembly.Save ();
 675
 676                         if (host == null)
 677                                 return null;
 678
 679                         //
 680                         // Unlike Mono, .NET requires that the MethodInfo is fetched, it cant
 681                         // work from MethodBuilders.   Retarded, I know.
 682                         //
 683                         var tt = assembly.Builder.GetType (host.TypeBuilder.Name);
 684                         var mi = tt.GetMethod (expression_method.Name);
 685
 686                         if (host.Fields != null) {
 687                                 //
 688                                 // We need to then go from FieldBuilder to FieldInfo
 689                                 // or reflection gets confused (it basically gets confused, and variables override each
 690                                 // other).
 691                                 //
 692                                 foreach (Field field in host.Fields) {
 693                                         var fi = tt.GetField (field.Name);
 694
 695                                         Tuple<FieldSpec, FieldInfo> old;
 696
 697                                         // If a previous value was set, nullify it, so that we do
 698                                         // not leak memory
 699                                         if (fields.TryGetValue (field.Name, out old)) {
 700                                                 if (old.Item1.MemberType.IsStruct) {
 701                                                         //
 702                                                         // TODO: Clear fields for structs
 703                                                         //
 704                                                 } else {
 705                                                         try {
 706                                                                 old.Item2.SetValue (null, null);
 707                                                         } catch {
 708                                                         }
 709                                                 }
 710                                         }
 711
 712                                         fields[field.Name] = Tuple.Create (field.Spec, fi);
 713                                 }
 714                         }
 715
 716                         return (CompiledMethod) System.Delegate.CreateDelegate (typeof (CompiledMethod), mi);
 717 #endif
 718                 }
 719
 720                 /// <summary>
 721                 ///   A sentinel value used to indicate that no value was
 722                 ///   was set by the compiled function.   This is used to
 723                 ///   differentiate between a function not returning a
 724                 ///   value and null.
 725                 /// </summary>
 726                 internal static class QuitValue { }
 727
 728                 internal Tuple<FieldSpec, FieldInfo> LookupField (string name)
 729                 {
 730                         Tuple<FieldSpec, FieldInfo> fi;
 731                         fields.TryGetValue (name, out fi);
 732                         return fi;
 733                 }
 734
 735                 static string Quote (string s)
 736                 {
 737                         if (s.IndexOf ('"') != -1)
 738                                 s = s.Replace ("\"", "\\\"");
 739
 740                         return "\"" + s + "\"";
 741                 }
 742
 743                 public string GetUsing ()
 744                 {
 745                         StringBuilder sb = new StringBuilder ();
 746                         // TODO:
 747                         //foreach (object x in ns.using_alias_list)
 748                         //    sb.AppendFormat ("using {0};\n", x);
 749
 750                         foreach (var ue in source_file.NamespaceContainer.Usings) {
 751                                 sb.AppendFormat ("using {0};", ue.ToString ());
 752                                 sb.Append (Environment.NewLine);
 753                         }
 754
 755                         return sb.ToString ();
 756                 }
 757
 758                 internal ICollection<string> GetUsingList ()
 759                 {
 760                         var res = new List<string> ();
 761
 762                         foreach (var ue in source_file.NamespaceContainer.Usings)
 763                                 res.Add (ue.Name);
 764                         return res;
 765                 }
 766
 767                 internal string [] GetVarNames ()
 768                 {
 769                         lock (evaluator_lock){
 770                                 return new List<string> (fields.Keys).ToArray ();
 771                         }
 772                 }
 773
 774                 public string GetVars ()
 775                 {
 776                         lock (evaluator_lock){
 777                                 StringBuilder sb = new StringBuilder ();
 778
 779                                 foreach (var de in fields){
 780                                         var fi = LookupField (de.Key);
 781                                         object value;
 782                                         try {
 783                                                 value = fi.Item2.GetValue (null);
 784                                                 if (value is string)
 785                                                         value = Quote ((string)value);
 786                                         } catch {
 787                                                 value = "<error reading value>";
 788                                         }
 789
 790                                         sb.AppendFormat ("{0} {1} = {2}", fi.Item1.MemberType.GetSignatureForError (), de.Key, value);
 791                                         sb.AppendLine ();
 792                                 }
 793
 794                                 return sb.ToString ();
 795                         }
 796                 }
 797
 798                 /// <summary>
 799                 ///    Loads the given assembly and exposes the API to the user.
 800                 /// </summary>
 801                 public void LoadAssembly (string file)
 802                 {
 803                         var loader = new DynamicLoader (importer, ctx);
 804                         var assembly = loader.LoadAssemblyFile (file);
 805                         if (assembly == null)
 806                                 return;
 807
 808                         lock (evaluator_lock){
 809                                 importer.ImportAssembly (assembly, module.GlobalRootNamespace);
 810                         }
 811                 }
 812
 813                 /// <summary>
 814                 ///    Exposes the API of the given assembly to the Evaluator
 815                 /// </summary>
 816                 public void ReferenceAssembly (Assembly a)
 817                 {
 818                         lock (evaluator_lock){
 819                                 importer.ImportAssembly (a, module.GlobalRootNamespace);
 820                         }
 821                 }
 822         }
 823
 824
 825         /// <summary>
 826         ///   A delegate that can be used to invoke the
 827         ///   compiled expression or statement.
 828         /// </summary>
 829         /// <remarks>
 830         ///   Since the Compile methods will compile
 831         ///   statements and expressions into the same
 832         ///   delegate, you can tell if a value was returned
 833         ///   by checking whether the returned value is of type
 834         ///   NoValueSet.
 835         /// </remarks>
 836
 837         public delegate void CompiledMethod (ref object retvalue);
 838
 839         /// <summary>
 840         ///   The default base class for every interaction line
 841         /// </summary>
 842         /// <remarks>
 843         ///   The expressions and statements behave as if they were
 844         ///   a static method of this class.   The InteractiveBase class
 845         ///   contains a number of useful methods, but can be overwritten
 846         ///   by setting the InteractiveBaseType property in the Evaluator
 847         /// </remarks>
 848         public class InteractiveBase {
 849                 /// <summary>
 850                 ///   Determines where the standard output of methods in this class will go.
 851                 /// </summary>
 852                 public static TextWriter Output = Console.Out;
 853
 854                 /// <summary>
 855                 ///   Determines where the standard error of methods in this class will go.
 856                 /// </summary>
 857                 public static TextWriter Error = Console.Error;
 858
 859                 /// <summary>
 860                 ///   The primary prompt used for interactive use.
 861                 /// </summary>
 862                 public static string Prompt             = "csharp> ";
 863
 864                 /// <summary>
 865                 ///   The secondary prompt used for interactive use (used when
 866                 ///   an expression is incomplete).
 867                 /// </summary>
 868                 public static string ContinuationPrompt = "      > ";
 869
 870                 /// <summary>
 871                 ///   Used to signal that the user has invoked the  `quit' statement.
 872                 /// </summary>
 873                 public static bool QuitRequested;
 874
 875                 public static Evaluator Evaluator;
 876
 877                 /// <summary>
 878                 ///   Shows all the variables defined so far.
 879                 /// </summary>
 880                 static public void ShowVars ()
 881                 {
 882                         Output.Write (Evaluator.GetVars ());
 883                         Output.Flush ();
 884                 }
 885
 886                 /// <summary>
 887                 ///   Displays the using statements in effect at this point.
 888                 /// </summary>
 889                 static public void ShowUsing ()
 890                 {
 891                         Output.Write (Evaluator.GetUsing ());
 892                         Output.Flush ();
 893                 }
 894
 895                 /// <summary>
 896                 ///   Times the execution of the given delegate
 897                 /// </summary>
 898                 static public TimeSpan Time (Action a)
 899                 {
 900                         DateTime start = DateTime.Now;
 901                         a ();
 902                         return DateTime.Now - start;
 903                 }
 904
 905                 /// <summary>
 906                 ///   Loads the assemblies from a package
 907                 /// </summary>
 908                 /// <remarks>
 909                 ///   Loads the assemblies from a package.   This is equivalent
 910                 ///   to passing the -pkg: command line flag to the C# compiler
 911                 ///   on the command line.
 912                 /// </remarks>
 913                 static public void LoadPackage (string pkg)
 914                 {
 915                         if (pkg == null){
 916                                 Error.WriteLine ("Invalid package specified");
 917                                 return;
 918                         }
 919
 920                         string pkgout = Driver.GetPackageFlags (pkg, null);
 921
 922                         string [] xargs = pkgout.Trim (new Char [] {' ', '\n', '\r', '\t'}).
 923                                 Split (new Char [] { ' ', '\t'});
 924
 925                         foreach (string s in xargs){
 926                                 if (s.StartsWith ("-r:") || s.StartsWith ("/r:") || s.StartsWith ("/reference:")){
 927                                         string lib = s.Substring (s.IndexOf (':')+1);
 928
 929                                         Evaluator.LoadAssembly (lib);
 930                                         continue;
 931                                 }
 932                         }
 933                 }
 934
 935                 /// <summary>
 936                 ///   Loads the assembly
 937                 /// </summary>
 938                 /// <remarks>
 939                 ///   Loads the specified assembly and makes its types
 940                 ///   available to the evaluator.  This is equivalent
 941                 ///   to passing the -pkg: command line flag to the C#
 942                 ///   compiler on the command line.
 943                 /// </remarks>
 944                 static public void LoadAssembly (string assembly)
 945                 {
 946                         Evaluator.LoadAssembly (assembly);
 947                 }
 948
 949                 static public void print (object obj)
 950                 {
 951                         Output.WriteLine (obj);
 952                 }
 953
 954                 static public void print (string fmt, params object [] args)
 955                 {
 956                         Output.WriteLine (fmt, args);
 957                 }
 958
 959                 /// <summary>
 960                 ///   Returns a list of available static methods.
 961                 /// </summary>
 962                 static public string help {
 963                         get {
 964                                 return "Static methods:\n" +
 965                                         "  Describe (object)       - Describes the object's type\n" +
 966                                         "  LoadPackage (package);  - Loads the given Package (like -pkg:FILE)\n" +
 967                                         "  LoadAssembly (assembly) - Loads the given assembly (like -r:ASSEMBLY)\n" +
 968                                         "  ShowVars ();            - Shows defined local variables.\n" +
 969                                         "  ShowUsing ();           - Show active using declarations.\n" +
 970                                         "  Prompt                  - The prompt used by the C# shell\n" +
 971                                         "  ContinuationPrompt      - The prompt for partial input\n" +
 972                                         "  Time(() -> { })         - Times the specified code\n" +
 973                                         "  print (obj)             - Shorthand for Console.WriteLine\n" +
 974                                         "  quit;                   - You'll never believe it - this quits the repl!\n" +
 975                                         "  help;                   - This help text\n";
 976                         }
 977                 }
 978
 979                 /// <summary>
 980                 ///   Indicates to the read-eval-print-loop that the interaction should be finished.
 981                 /// </summary>
 982                 static public object quit {
 983                         get {
 984                                 QuitRequested = true;
 985
 986                                 // To avoid print null at the exit
 987                                 return typeof (Evaluator.QuitValue);
 988                         }
 989                 }
 990
 991 #if !NET_2_1
 992                 /// <summary>
 993                 ///   Describes an object or a type.
 994                 /// </summary>
 995                 /// <remarks>
 996                 ///   This method will show a textual representation
 997                 ///   of the object's type.  If the object is a
 998                 ///   System.Type it renders the type directly,
 999                 ///   otherwise it renders the type returned by
1000                 ///   invoking GetType on the object.
1001                 /// </remarks>
1002                 static public string Describe (object x)
1003                 {
1004                         if (x == null)
1005                                 return "<null>";
1006
1007                         var type = x as Type ?? x.GetType ();
1008
1009                         StringWriter sw = new StringWriter ();
1010                         new Outline (type, sw, true, false, false).OutlineType ();
1011                         return sw.ToString ();
1012                 }
1013 #endif
1014         }
1015
1016         class HoistedEvaluatorVariable : HoistedVariable
1017         {
1018                 public HoistedEvaluatorVariable (Field field)
1019                         : base (null, field)
1020                 {
1021                 }
1022
1023                 public override void EmitSymbolInfo ()
1024                 {
1025                 }
1026
1027                 protected override FieldExpr GetFieldExpression (EmitContext ec)
1028                 {
1029                         return new FieldExpr (field, field.Location);
1030                 }
1031         }
1032
1033         /// <summary>
1034         ///    A class used to assign values if the source expression is not void
1035         ///
1036         ///    Used by the interactive shell to allow it to call this code to set
1037         ///    the return value for an invocation.
1038         /// </summary>
1039         class OptionalAssign : SimpleAssign {
1040                 public OptionalAssign (Expression t, Expression s, Location loc)
1041                         : base (t, s, loc)
1042                 {
1043                 }
1044
1045                 protected override Expression DoResolve (ResolveContext ec)
1046                 {
1047                         Expression clone = source.Clone (new CloneContext ());
1048
1049                         clone = clone.Resolve (ec);
1050                         if (clone == null)
1051                                 return null;
1052
1053                         //
1054                         // A useful feature for the REPL: if we can resolve the expression
1055                         // as a type, Describe the type;
1056                         //
1057                         if (ec.Module.Evaluator.DescribeTypeExpressions){
1058                                 var old_printer = ec.Report.SetPrinter (new SessionReportPrinter ());
1059                                 Expression tclone;
1060                                 try {
1061                                         // Note: clone context cannot be shared otherwise block mapping would leak
1062                                         tclone = source.Clone (new CloneContext ());
1063                                         tclone = tclone.Resolve (ec, ResolveFlags.Type);
1064                                         if (ec.Report.Errors > 0)
1065                                                 tclone = null;
1066                                 } finally {
1067                                         ec.Report.SetPrinter (old_printer);
1068                                 }
1069
1070                                 if (tclone != null) {
1071                                         Arguments args = new Arguments (1);
1072                                         args.Add (new Argument (new TypeOf ((TypeExpr) clone, Location)));
1073                                         return new Invocation (new SimpleName ("Describe", Location), args).Resolve (ec);
1074                                 }
1075                         }
1076
1077                         // This means its really a statement.
1078                         if (clone.Type.Kind == MemberKind.Void || clone is DynamicInvocation || clone is Assign) {
1079                                 return clone;
1080                         }
1081
1082                         source = clone;
1083                         return base.DoResolve (ec);
1084                 }
1085         }
1086
1087         public class Undo
1088         {
1089                 List<Action> undo_actions;
1090
1091                 public Undo ()
1092                 {
1093                 }
1094
1095                 public void AddTypeContainer (TypeContainer current_container, TypeContainer tc)
1096                 {
1097                         if (current_container == tc){
1098                                 Console.Error.WriteLine ("Internal error: inserting container into itself");
1099                                 return;
1100                         }
1101
1102                         if (undo_actions == null)
1103                                 undo_actions = new List<Action> ();
1104
1105                         var existing = current_container.Types.FirstOrDefault (l => l.MemberName.Basename == tc.MemberName.Basename);
1106                         if (existing != null) {
1107                                 current_container.RemoveTypeContainer (existing);
1108                                 existing.NamespaceEntry.SlaveDeclSpace.RemoveTypeContainer (existing);
1109                                 undo_actions.Add (() => current_container.AddTypeContainer (existing));
1110                         }
1111
1112                         undo_actions.Add (() => current_container.RemoveTypeContainer (tc));
1113                 }
1114
1115                 public void ExecuteUndo ()
1116                 {
1117                         if (undo_actions == null)
1118                                 return;
1119
1120                         foreach (var p in undo_actions){
1121                                 p ();
1122                         }
1123
1124                         undo_actions = null;
1125                 }
1126         }
1127
1128 }