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 //
   7 // Dual licensed under the terms of the MIT X11 or GNU GPL
   8 //
   9 // Copyright 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
  10 // Copyright 2004, 2005, 2006, 2007, 2008 Novell, Inc
  11 //
  12
  13 using System;
  14 using System.Threading;
  15 using System.Collections.Generic;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.IO;
  19 using System.Text;
  20
  21 namespace Mono.CSharp
  22 {
  23
  24         /// <summary>
  25         ///   Evaluator: provides an API to evaluate C# statements and
  26         ///   expressions dynamically.
  27         /// </summary>
  28         /// <remarks>
  29         ///   This class exposes static methods to evaluate expressions in the
  30         ///   current program.
  31         ///
  32         ///   To initialize the evaluator with a number of compiler
  33         ///   options call the Init(string[]args) method with a set of
  34         ///   command line options that the compiler recognizes.
  35         ///
  36         ///   To interrupt execution of a statement, you can invoke the
  37         ///   Evaluator.Interrupt method.
  38         /// </remarks>
  39         public class Evaluator {
  40
  41                 enum ParseMode {
  42                         // Parse silently, do not output any error messages
  43                         Silent,
  44
  45                         // Report errors during parse
  46                         ReportErrors,
  47
  48                         // Auto-complete, means that the tokenizer will start producing
  49                         // GETCOMPLETIONS tokens when it reaches a certain point.
  50                         GetCompletions
  51                 }
  52
  53                 static object evaluator_lock = new object ();
  54
  55                 static string current_debug_name;
  56                 static int count;
  57                 static Thread invoke_thread;
  58
  59                 static List<NamespaceEntry.UsingAliasEntry> using_alias_list = new List<NamespaceEntry.UsingAliasEntry> ();
  60                 internal static List<NamespaceEntry.UsingEntry> using_list = new List<NamespaceEntry.UsingEntry> ();
  61                 static Dictionary<string, Tuple<FieldSpec, FieldInfo>> fields = new Dictionary<string, Tuple<FieldSpec, FieldInfo>> ();
  62
  63                 static TypeSpec interactive_base_class;
  64                 static Driver driver;
  65                 static bool inited;
  66
  67                 static CompilerContext ctx;
  68                 static DynamicLoader loader;
  69
  70                 public static TextWriter MessageOutput = Console.Out;
  71
  72                 /// <summary>
  73                 ///   Optional initialization for the Evaluator.
  74                 /// </summary>
  75                 /// <remarks>
  76                 ///  Initializes the Evaluator with the command line options
  77                 ///  that would be processed by the command line compiler.  Only
  78                 ///  the first call to Init will work, any future invocations are
  79                 ///  ignored.
  80                 ///
  81                 ///  You can safely avoid calling this method if your application
  82                 ///  does not need any of the features exposed by the command line
  83                 ///  interface.
  84                 /// </remarks>
  85                 public static void Init (string [] args)
  86                 {
  87                         InitAndGetStartupFiles (args);
  88                 }
  89
  90                 internal static ReportPrinter SetPrinter (ReportPrinter report_printer)
  91                 {
  92                         return ctx.Report.SetPrinter (report_printer);
  93                 }
  94
  95                 /// <summary>
  96                 ///   Optional initialization for the Evaluator.
  97                 /// </summary>
  98                 /// <remarks>
  99                 ///  Initializes the Evaluator with the command line
 100                 ///  options that would be processed by the command
 101                 ///  line compiler.  Only the first call to
 102                 ///  InitAndGetStartupFiles or Init will work, any future
 103                 ///  invocations are ignored.
 104                 ///
 105                 ///  You can safely avoid calling this method if your application
 106                 ///  does not need any of the features exposed by the command line
 107                 ///  interface.
 108                 ///
 109                 ///  This method return an array of strings that contains any
 110                 ///  files that were specified in `args'.
 111                 /// </remarks>
 112                 public static string [] InitAndGetStartupFiles (string [] args)
 113                 {
 114                         lock (evaluator_lock){
 115                                 if (inited)
 116                                         return new string [0];
 117
 118                                 var crp = new ConsoleReportPrinter ();
 119                                 driver = Driver.Create (args, false, crp);
 120                                 if (driver == null)
 121                                         throw new Exception ("Failed to create compiler driver with the given arguments");
 122
 123                                 crp.Fatal = driver.fatal_errors;
 124                                 ctx = driver.ctx;
 125
 126                                 CompilerCallableEntryPoint.Reset ();
 127                                 RootContext.ToplevelTypes = new ModuleContainer (ctx);
 128
 129                                 var startup_files = new List<string> ();
 130                                 foreach (CompilationUnit file in Location.SourceFiles)
 131                                         startup_files.Add (file.Path);
 132
 133                                 CompilerCallableEntryPoint.PartialReset ();
 134
 135                                 var importer = new ReflectionImporter (ctx.BuildinTypes);
 136                                 loader = new DynamicLoader (importer, ctx);
 137
 138                                 RootContext.ToplevelTypes.SetDeclaringAssembly (new AssemblyDefinitionDynamic (RootContext.ToplevelTypes, "temp"));
 139
 140                                 loader.LoadReferences (RootContext.ToplevelTypes);
 141                                 ctx.BuildinTypes.CheckDefinitions (RootContext.ToplevelTypes);
 142                                 RootContext.ToplevelTypes.InitializePredefinedTypes ();
 143
 144                                 RootContext.EvalMode = true;
 145                                 inited = true;
 146
 147                                 return startup_files.ToArray ();
 148                         }
 149                 }
 150
 151                 static void Init ()
 152                 {
 153                         Init (new string [0]);
 154                 }
 155
 156                 static void Reset ()
 157                 {
 158                         CompilerCallableEntryPoint.PartialReset ();
 159
 160                         Location.AddFile (null, "{interactive}");
 161                         Location.Initialize ();
 162
 163                         current_debug_name = "interactive" + (count++) + ".dll";
 164                 }
 165
 166                 /// <summary>
 167                 ///   The base class for the classes that host the user generated code
 168                 /// </summary>
 169                 /// <remarks>
 170                 ///
 171                 ///   This is the base class that will host the code
 172                 ///   executed by the Evaluator.  By default
 173                 ///   this is the Mono.CSharp.InteractiveBase class
 174                 ///   which is useful for interactive use.
 175                 ///
 176                 ///   By changing this property you can control the
 177                 ///   base class and the static members that are
 178                 ///   available to your evaluated code.
 179                 /// </remarks>
 180                 static public TypeSpec InteractiveBaseClass {
 181                         get {
 182                                 if (interactive_base_class != null)
 183                                         return interactive_base_class;
 184
 185                                 return loader.Importer.ImportType (typeof (InteractiveBase));
 186                         }
 187                 }
 188
 189                 public static void SetInteractiveBaseClass (Type type)
 190                 {
 191                         if (type == null)
 192                                 throw new ArgumentNullException ();
 193
 194                         if (!inited)
 195                                 throw new Exception ("Evaluator has to be initiated before seting custom InteractiveBase class");
 196
 197                         lock (evaluator_lock)
 198                                 interactive_base_class = loader.Importer.ImportType (type);
 199                 }
 200
 201                 /// <summary>
 202                 ///   Interrupts the evaluation of an expression executing in Evaluate.
 203                 /// </summary>
 204                 /// <remarks>
 205                 ///   Use this method to interrupt long-running invocations.
 206                 /// </remarks>
 207                 public static void Interrupt ()
 208                 {
 209                         if (!inited || !invoking)
 210                                 return;
 211
 212                         if (invoke_thread != null)
 213                                 invoke_thread.Abort ();
 214                 }
 215
 216                 /// <summary>
 217                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 218                 /// </summary>
 219                 /// <remarks>
 220                 ///
 221                 ///   Compiles the input string as a C# expression or
 222                 ///   statement, unlike the Evaluate method, the
 223                 ///   resulting delegate can be invoked multiple times
 224                 ///   without incurring in the compilation overhead.
 225                 ///
 226                 ///   If the return value of this function is null,
 227                 ///   this indicates that the parsing was complete.
 228                 ///   If the return value is a string it indicates
 229                 ///   that the input string was partial and that the
 230                 ///   invoking code should provide more code before
 231                 ///   the code can be successfully compiled.
 232                 ///
 233                 ///   If you know that you will always get full expressions or
 234                 ///   statements and do not care about partial input, you can use
 235                 ///   the other Compile overload.
 236                 ///
 237                 ///   On success, in addition to returning null, the
 238                 ///   compiled parameter will be set to the delegate
 239                 ///   that can be invoked to execute the code.
 240                 ///
 241                 /// </remarks>
 242                 static public string Compile (string input, out CompiledMethod compiled)
 243                 {
 244                         if (input == null || input.Length == 0){
 245                                 compiled = null;
 246                                 return null;
 247                         }
 248
 249                         lock (evaluator_lock){
 250                                 if (!inited)
 251                                         Init ();
 252                                 else
 253                                         ctx.Report.Printer.Reset ();
 254
 255                         //      RootContext.ToplevelTypes = new ModuleContainer (ctx);
 256
 257                                 bool partial_input;
 258                                 CSharpParser parser = ParseString (ParseMode.Silent, input, out partial_input);
 259                                 if (parser == null){
 260                                         compiled = null;
 261                                         if (partial_input)
 262                                                 return input;
 263
 264                                         ParseString (ParseMode.ReportErrors, input, out partial_input);
 265                                         return null;
 266                                 }
 267
 268                                 object parser_result = parser.InteractiveResult;
 269
 270                                 if (!(parser_result is Class)){
 271                                         int errors = ctx.Report.Errors;
 272
 273                                         NamespaceEntry.VerifyAllUsing ();
 274                                         if (errors == ctx.Report.Errors)
 275                                                 parser.CurrentNamespace.Extract (using_alias_list, using_list);
 276                                         else
 277                                                 NamespaceEntry.Reset ();
 278                                 }
 279
 280 #if STATIC
 281                                 throw new NotSupportedException ();
 282 #else
 283                                 compiled = CompileBlock (parser_result as Class, parser.undo, ctx.Report);
 284                                 return null;
 285 #endif
 286                         }
 287                 }
 288
 289                 /// <summary>
 290                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 291                 /// </summary>
 292                 /// <remarks>
 293                 ///
 294                 ///   Compiles the input string as a C# expression or
 295                 ///   statement, unlike the Evaluate method, the
 296                 ///   resulting delegate can be invoked multiple times
 297                 ///   without incurring in the compilation overhead.
 298                 ///
 299                 ///   This method can only deal with fully formed input
 300                 ///   strings and does not provide a completion mechanism.
 301                 ///   If you must deal with partial input (for example for
 302                 ///   interactive use) use the other overload.
 303                 ///
 304                 ///   On success, a delegate is returned that can be used
 305                 ///   to invoke the method.
 306                 ///
 307                 /// </remarks>
 308                 static public CompiledMethod Compile (string input)
 309                 {
 310                         CompiledMethod compiled;
 311
 312                         // Ignore partial inputs
 313                         if (Compile (input, out compiled) != null){
 314                                 // Error, the input was partial.
 315                                 return null;
 316                         }
 317
 318                         // Either null (on error) or the compiled method.
 319                         return compiled;
 320                 }
 321
 322                 //
 323                 // Todo: Should we handle errors, or expect the calling code to setup
 324                 // the recording themselves?
 325                 //
 326
 327                 /// <summary>
 328                 ///   Evaluates and expression or statement and returns any result values.
 329                 /// </summary>
 330                 /// <remarks>
 331                 ///   Evaluates the input string as a C# expression or
 332                 ///   statement.  If the input string is an expression
 333                 ///   the result will be stored in the result variable
 334                 ///   and the result_set variable will be set to true.
 335                 ///
 336                 ///   It is necessary to use the result/result_set
 337                 ///   pair to identify when a result was set (for
 338                 ///   example, execution of user-provided input can be
 339                 ///   an expression, a statement or others, and
 340                 ///   result_set would only be set if the input was an
 341                 ///   expression.
 342                 ///
 343                 ///   If the return value of this function is null,
 344                 ///   this indicates that the parsing was complete.
 345                 ///   If the return value is a string, it indicates
 346                 ///   that the input is partial and that the user
 347                 ///   should provide an updated string.
 348                 /// </remarks>
 349                 public static string Evaluate (string input, out object result, out bool result_set)
 350                 {
 351                         CompiledMethod compiled;
 352
 353                         result_set = false;
 354                         result = null;
 355
 356                         input = Compile (input, out compiled);
 357                         if (input != null)
 358                                 return input;
 359
 360                         if (compiled == null)
 361                                 return null;
 362
 363                         //
 364                         // The code execution does not need to keep the compiler lock
 365                         //
 366                         object retval = typeof (NoValueSet);
 367
 368                         try {
 369                                 invoke_thread = System.Threading.Thread.CurrentThread;
 370                                 invoking = true;
 371                                 compiled (ref retval);
 372                         } catch (ThreadAbortException e){
 373                                 Thread.ResetAbort ();
 374                                 Console.WriteLine ("Interrupted!\n{0}", e);
 375                         } finally {
 376                                 invoking = false;
 377                         }
 378
 379                         //
 380                         // We use a reference to a compiler type, in this case
 381                         // Driver as a flag to indicate that this was a statement
 382                         //
 383                         if (retval != typeof (NoValueSet)){
 384                                 result_set = true;
 385                                 result = retval;
 386                         }
 387
 388                         return null;
 389                 }
 390
 391                 public static string [] GetCompletions (string input, out string prefix)
 392                 {
 393                         prefix = "";
 394                         if (input == null || input.Length == 0)
 395                                 return null;
 396
 397                         lock (evaluator_lock){
 398                                 if (!inited)
 399                                         Init ();
 400
 401                                 bool partial_input;
 402                                 CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
 403                                 if (parser == null){
 404                                         if (CSharpParser.yacc_verbose_flag != 0)
 405                                                 Console.WriteLine ("DEBUG: No completions available");
 406                                         return null;
 407                                 }
 408
 409                                 Class parser_result = parser.InteractiveResult as Class;
 410
 411                                 if (parser_result == null){
 412                                         if (CSharpParser.yacc_verbose_flag != 0)
 413                                                 Console.WriteLine ("Do not know how to cope with !Class yet");
 414                                         return null;
 415                                 }
 416
 417                                 try {
 418                                         var a = new AssemblyDefinitionDynamic (RootContext.ToplevelTypes, "temp");
 419                                         a.Create (AppDomain.CurrentDomain, AssemblyBuilderAccess.Run);
 420                                         RootContext.ToplevelTypes.SetDeclaringAssembly (a);
 421                                         RootContext.ToplevelTypes.CreateType ();
 422                                         RootContext.ToplevelTypes.Define ();
 423                                         if (ctx.Report.Errors != 0)
 424                                                 return null;
 425
 426                                         MethodOrOperator method = null;
 427                                         foreach (MemberCore member in parser_result.Methods){
 428                                                 if (member.Name != "Host")
 429                                                         continue;
 430
 431                                                 method = (MethodOrOperator) member;
 432                                                 break;
 433                                         }
 434                                         if (method == null)
 435                                                 throw new InternalErrorException ("did not find the the Host method");
 436
 437                                         BlockContext bc = new BlockContext (method, method.Block, method.ReturnType);
 438
 439                                         try {
 440                                                 method.Block.Resolve (null, bc, method);
 441                                         } catch (CompletionResult cr){
 442                                                 prefix = cr.BaseText;
 443                                                 return cr.Result;
 444                                         }
 445                                 } finally {
 446                                         parser.undo.ExecuteUndo ();
 447                                 }
 448
 449                         }
 450                         return null;
 451                 }
 452
 453                 /// <summary>
 454                 ///   Executes the given expression or statement.
 455                 /// </summary>
 456                 /// <remarks>
 457                 ///    Executes the provided statement, returns true
 458                 ///    on success, false on parsing errors.  Exceptions
 459                 ///    might be thrown by the called code.
 460                 /// </remarks>
 461                 public static bool Run (string statement)
 462                 {
 463                         if (!inited)
 464                                 Init ();
 465
 466                         object result;
 467                         bool result_set;
 468
 469                         bool ok = Evaluate (statement, out result, out result_set) == null;
 470
 471                         return ok;
 472                 }
 473
 474                 /// <summary>
 475                 ///   Evaluates and expression or statement and returns the result.
 476                 /// </summary>
 477                 /// <remarks>
 478                 ///   Evaluates the input string as a C# expression or
 479                 ///   statement and returns the value.
 480                 ///
 481                 ///   This method will throw an exception if there is a syntax error,
 482                 ///   of if the provided input is not an expression but a statement.
 483                 /// </remarks>
 484                 public static object Evaluate (string input)
 485                 {
 486                         object result;
 487                         bool result_set;
 488
 489                         string r = Evaluate (input, out result, out result_set);
 490
 491                         if (r != null)
 492                                 throw new ArgumentException ("Syntax error on input: partial input");
 493
 494                         if (result_set == false)
 495                                 throw new ArgumentException ("The expression did not set a result");
 496
 497                         return result;
 498                 }
 499
 500                 enum InputKind {
 501                         EOF,
 502                         StatementOrExpression,
 503                         CompilationUnit,
 504                         Error
 505                 }
 506
 507                 //
 508                 // Deambiguates the input string to determine if we
 509                 // want to process a statement or if we want to
 510                 // process a compilation unit.
 511                 //
 512                 // This is done using a top-down predictive parser,
 513                 // since the yacc/jay parser can not deambiguage this
 514                 // without more than one lookahead token.   There are very
 515                 // few ambiguities.
 516                 //
 517                 static InputKind ToplevelOrStatement (SeekableStreamReader seekable)
 518                 {
 519                         Tokenizer tokenizer = new Tokenizer (seekable, (CompilationUnit) Location.SourceFiles [0], ctx);
 520
 521                         int t = tokenizer.token ();
 522                         switch (t){
 523                         case Token.EOF:
 524                                 return InputKind.EOF;
 525
 526                         // These are toplevels
 527                         case Token.EXTERN:
 528                         case Token.OPEN_BRACKET:
 529                         case Token.ABSTRACT:
 530                         case Token.CLASS:
 531                         case Token.ENUM:
 532                         case Token.INTERFACE:
 533                         case Token.INTERNAL:
 534                         case Token.NAMESPACE:
 535                         case Token.PRIVATE:
 536                         case Token.PROTECTED:
 537                         case Token.PUBLIC:
 538                         case Token.SEALED:
 539                         case Token.STATIC:
 540                         case Token.STRUCT:
 541                                 return InputKind.CompilationUnit;
 542
 543                         // Definitely expression
 544                         case Token.FIXED:
 545                         case Token.BOOL:
 546                         case Token.BYTE:
 547                         case Token.CHAR:
 548                         case Token.DECIMAL:
 549                         case Token.DOUBLE:
 550                         case Token.FLOAT:
 551                         case Token.INT:
 552                         case Token.LONG:
 553                         case Token.NEW:
 554                         case Token.OBJECT:
 555                         case Token.SBYTE:
 556                         case Token.SHORT:
 557                         case Token.STRING:
 558                         case Token.UINT:
 559                         case Token.ULONG:
 560                                 return InputKind.StatementOrExpression;
 561
 562                         // These need deambiguation help
 563                         case Token.USING:
 564                                 t = tokenizer.token ();
 565                                 if (t == Token.EOF)
 566                                         return InputKind.EOF;
 567
 568                                 if (t == Token.IDENTIFIER)
 569                                         return InputKind.CompilationUnit;
 570                                 return InputKind.StatementOrExpression;
 571
 572
 573                         // Distinguish between:
 574                         //    delegate opt_anonymous_method_signature block
 575                         //    delegate type
 576                         case Token.DELEGATE:
 577                                 t = tokenizer.token ();
 578                                 if (t == Token.EOF)
 579                                         return InputKind.EOF;
 580                                 if (t == Token.OPEN_PARENS || t == Token.OPEN_BRACE)
 581                                         return InputKind.StatementOrExpression;
 582                                 return InputKind.CompilationUnit;
 583
 584                         // Distinguih between:
 585                         //    unsafe block
 586                         //    unsafe as modifier of a type declaration
 587                         case Token.UNSAFE:
 588                                 t = tokenizer.token ();
 589                                 if (t == Token.EOF)
 590                                         return InputKind.EOF;
 591                                 if (t == Token.OPEN_PARENS)
 592                                         return InputKind.StatementOrExpression;
 593                                 return InputKind.CompilationUnit;
 594
 595                         // These are errors: we list explicitly what we had
 596                         // from the grammar, ERROR and then everything else
 597
 598                         case Token.READONLY:
 599                         case Token.OVERRIDE:
 600                         case Token.ERROR:
 601                                 return InputKind.Error;
 602
 603                         // This catches everything else allowed by
 604                         // expressions.  We could add one-by-one use cases
 605                         // if needed.
 606                         default:
 607                                 return InputKind.StatementOrExpression;
 608                         }
 609                 }
 610
 611                 //
 612                 // Parses the string @input and returns a CSharpParser if succeeful.
 613                 //
 614                 // if @silent is set to true then no errors are
 615                 // reported to the user.  This is used to do various calls to the
 616                 // parser and check if the expression is parsable.
 617                 //
 618                 // @partial_input: if @silent is true, then it returns whether the
 619                 // parsed expression was partial, and more data is needed
 620                 //
 621                 static CSharpParser ParseString (ParseMode mode, string input, out bool partial_input)
 622                 {
 623                         partial_input = false;
 624                         Reset ();
 625                         queued_fields.Clear ();
 626                         Tokenizer.LocatedToken.Initialize ();
 627
 628                         Stream s = new MemoryStream (Encoding.Default.GetBytes (input));
 629                         SeekableStreamReader seekable = new SeekableStreamReader (s, Encoding.Default);
 630
 631                         InputKind kind = ToplevelOrStatement (seekable);
 632                         if (kind == InputKind.Error){
 633                                 if (mode == ParseMode.ReportErrors)
 634                                         ctx.Report.Error (-25, "Detection Parsing Error");
 635                                 partial_input = false;
 636                                 return null;
 637                         }
 638
 639                         if (kind == InputKind.EOF){
 640                                 if (mode == ParseMode.ReportErrors)
 641                                         Console.Error.WriteLine ("Internal error: EOF condition should have been detected in a previous call with silent=true");
 642                                 partial_input = true;
 643                                 return null;
 644
 645                         }
 646                         seekable.Position = 0;
 647
 648                         CSharpParser parser = new CSharpParser (seekable, Location.SourceFiles [0], RootContext.ToplevelTypes);
 649
 650                         if (kind == InputKind.StatementOrExpression){
 651                                 parser.Lexer.putback_char = Tokenizer.EvalStatementParserCharacter;
 652                                 RootContext.StatementMode = true;
 653                         } else {
 654                                 //
 655                                 // Do not activate EvalCompilationUnitParserCharacter until
 656                                 // I have figured out all the limitations to invoke methods
 657                                 // in the generated classes.  See repl.txt
 658                                 //
 659                                 parser.Lexer.putback_char = Tokenizer.EvalUsingDeclarationsParserCharacter;
 660                                 //parser.Lexer.putback_char = Tokenizer.EvalCompilationUnitParserCharacter;
 661                                 RootContext.StatementMode = false;
 662                         }
 663
 664                         if (mode == ParseMode.GetCompletions)
 665                                 parser.Lexer.CompleteOnEOF = true;
 666
 667                         ReportPrinter old_printer = null;
 668                         if ((mode == ParseMode.Silent || mode == ParseMode.GetCompletions) && CSharpParser.yacc_verbose_flag == 0)
 669                                 old_printer = SetPrinter (new StreamReportPrinter (TextWriter.Null));
 670
 671                         try {
 672                                 parser.parse ();
 673                         } finally {
 674                                 if (ctx.Report.Errors != 0){
 675                                         if (mode != ParseMode.ReportErrors  && parser.UnexpectedEOF)
 676                                                 partial_input = true;
 677
 678                                         parser.undo.ExecuteUndo ();
 679                                         parser = null;
 680                                 }
 681
 682                                 if (old_printer != null)
 683                                         SetPrinter (old_printer);
 684                         }
 685                         return parser;
 686                 }
 687
 688                 //
 689                 // Queue all the fields that we use, as we need to then go from FieldBuilder to FieldInfo
 690                 // or reflection gets confused (it basically gets confused, and variables override each
 691                 // other).
 692                 //
 693                 static List<Field> queued_fields = new List<Field> ();
 694
 695                 //static ArrayList types = new ArrayList ();
 696
 697                 static volatile bool invoking;
 698 #if !STATIC
 699                 static CompiledMethod CompileBlock (Class host, Undo undo, Report Report)
 700                 {
 701                         AssemblyDefinitionDynamic assembly;
 702
 703                         if (Environment.GetEnvironmentVariable ("SAVE") != null) {
 704                                 assembly = new AssemblyDefinitionDynamic (RootContext.ToplevelTypes, current_debug_name, current_debug_name);
 705                                 assembly.Importer = loader.Importer;
 706                         } else {
 707                                 assembly = new AssemblyDefinitionDynamic (RootContext.ToplevelTypes, current_debug_name);
 708                         }
 709
 710                         assembly.Create (AppDomain.CurrentDomain, AssemblyBuilderAccess.RunAndSave);
 711                         RootContext.ToplevelTypes.CreateType ();
 712                         RootContext.ToplevelTypes.Define ();
 713
 714                         if (Report.Errors != 0){
 715                                 undo.ExecuteUndo ();
 716                                 return null;
 717                         }
 718
 719                         TypeBuilder tb = null;
 720                         MethodBuilder mb = null;
 721
 722                         if (host != null){
 723                                 tb = host.TypeBuilder;
 724                                 mb = null;
 725                                 foreach (MemberCore member in host.Methods){
 726                                         if (member.Name != "Host")
 727                                                 continue;
 728
 729                                         MethodOrOperator method = (MethodOrOperator) member;
 730                                         mb = method.MethodBuilder;
 731                                         break;
 732                                 }
 733
 734                                 if (mb == null)
 735                                         throw new Exception ("Internal error: did not find the method builder for the generated method");
 736                         }
 737
 738                         RootContext.ToplevelTypes.Emit ();
 739                         if (Report.Errors != 0){
 740                                 undo.ExecuteUndo ();
 741                                 return null;
 742                         }
 743
 744                         RootContext.ToplevelTypes.CloseType ();
 745
 746                         if (Environment.GetEnvironmentVariable ("SAVE") != null)
 747                                 assembly.Save ();
 748
 749                         if (host == null)
 750                                 return null;
 751
 752                         //
 753                         // Unlike Mono, .NET requires that the MethodInfo is fetched, it cant
 754                         // work from MethodBuilders.   Retarded, I know.
 755                         //
 756                         var tt = assembly.Builder.GetType (tb.Name);
 757                         MethodInfo mi = tt.GetMethod (mb.Name);
 758
 759                         // Pull the FieldInfos from the type, and keep track of them
 760                         foreach (Field field in queued_fields){
 761                                 FieldInfo fi = tt.GetField (field.Name);
 762
 763                                 Tuple<FieldSpec, FieldInfo> old;
 764
 765                                 // If a previous value was set, nullify it, so that we do
 766                                 // not leak memory
 767                                 if (fields.TryGetValue (field.Name, out old)) {
 768                                         if (old.Item1.MemberType.IsStruct) {
 769                                                 //
 770                                                 // TODO: Clear fields for structs
 771                                                 //
 772                                         } else {
 773                                                 try {
 774                                                         old.Item2.SetValue (null, null);
 775                                                 } catch {
 776                                                 }
 777                                         }
 778
 779                                         fields [field.Name] = Tuple.Create (field.Spec, fi);
 780                                 } else {
 781                                         fields.Add (field.Name, Tuple.Create (field.Spec, fi));
 782                                 }
 783                         }
 784                         //types.Add (tb);
 785
 786                         queued_fields.Clear ();
 787
 788                         return (CompiledMethod) System.Delegate.CreateDelegate (typeof (CompiledMethod), mi);
 789                 }
 790 #endif
 791                 static internal void LoadAliases (NamespaceEntry ns)
 792                 {
 793                         ns.Populate (using_alias_list, using_list);
 794                 }
 795
 796                 /// <summary>
 797                 ///   A sentinel value used to indicate that no value was
 798                 ///   was set by the compiled function.   This is used to
 799                 ///   differentiate between a function not returning a
 800                 ///   value and null.
 801                 /// </summary>
 802                 public class NoValueSet {
 803                 }
 804
 805                 static internal Tuple<FieldSpec, FieldInfo> LookupField (string name)
 806                 {
 807                         Tuple<FieldSpec, FieldInfo> fi;
 808                         fields.TryGetValue (name, out fi);
 809                         return fi;
 810                 }
 811
 812                 //
 813                 // Puts the FieldBuilder into a queue of names that will be
 814                 // registered.   We can not register FieldBuilders directly
 815                 // we need to fetch the FieldInfo after Reflection cooks the
 816                 // types, or bad things happen (bad means: FieldBuilders behave
 817                 // incorrectly across multiple assemblies, causing assignments to
 818                 // invalid areas
 819                 //
 820                 // This also serves for the parser to register Field classes
 821                 // that should be exposed as global variables
 822                 //
 823                 static internal void QueueField (Field f)
 824                 {
 825                         queued_fields.Add (f);
 826                 }
 827
 828                 static string Quote (string s)
 829                 {
 830                         if (s.IndexOf ('"') != -1)
 831                                 s = s.Replace ("\"", "\\\"");
 832
 833                         return "\"" + s + "\"";
 834                 }
 835
 836                 static public string GetUsing ()
 837                 {
 838                         lock (evaluator_lock){
 839                                 StringBuilder sb = new StringBuilder ();
 840
 841                                 foreach (object x in using_alias_list)
 842                                         sb.Append (String.Format ("using {0};\n", x));
 843
 844                                 foreach (object x in using_list)
 845                                         sb.Append (String.Format ("using {0};\n", x));
 846
 847                                 return sb.ToString ();
 848                         }
 849                 }
 850
 851                 static internal ICollection<string> GetUsingList ()
 852                 {
 853                         var res = new List<string> (using_list.Count);
 854                         foreach (object ue in using_list)
 855                                 res.Add (ue.ToString ());
 856                         return res;
 857                 }
 858
 859                 static internal string [] GetVarNames ()
 860                 {
 861                         lock (evaluator_lock){
 862                                 return new List<string> (fields.Keys).ToArray ();
 863                         }
 864                 }
 865
 866                 static public string GetVars ()
 867                 {
 868                         lock (evaluator_lock){
 869                                 StringBuilder sb = new StringBuilder ();
 870
 871                                 foreach (var de in fields){
 872                                         var fi = LookupField (de.Key);
 873                                         object value;
 874                                         try {
 875                                                 value = fi.Item2.GetValue (null);
 876                                                 if (value is string)
 877                                                         value = Quote ((string)value);
 878                                         } catch {
 879                                                 value = "<error reading value>";
 880                                         }
 881
 882                                         sb.AppendFormat ("{0} {1} = {2}", fi.Item1.MemberType.GetSignatureForError (), de.Key, value);
 883                                         sb.AppendLine ();
 884                                 }
 885
 886                                 return sb.ToString ();
 887                         }
 888                 }
 889
 890                 /// <summary>
 891                 ///    Loads the given assembly and exposes the API to the user.
 892                 /// </summary>
 893                 static public void LoadAssembly (string file)
 894                 {
 895                         lock (evaluator_lock){
 896                                 var a = loader.LoadAssemblyFile (file);
 897                                 if (a != null)
 898                                         loader.Importer.ImportAssembly (a, RootContext.ToplevelTypes.GlobalRootNamespace);
 899                         }
 900                 }
 901
 902                 /// <summary>
 903                 ///    Exposes the API of the given assembly to the Evaluator
 904                 /// </summary>
 905                 static public void ReferenceAssembly (Assembly a)
 906                 {
 907                         lock (evaluator_lock){
 908                                 loader.Importer.ImportAssembly (a, RootContext.ToplevelTypes.GlobalRootNamespace);
 909                         }
 910                 }
 911
 912                 /// <summary>
 913                 ///   If true, turns type expressions into valid expressions
 914                 ///   and calls the describe method on it
 915                 /// </summary>
 916                 public static bool DescribeTypeExpressions;
 917         }
 918
 919
 920         /// <summary>
 921         ///   A delegate that can be used to invoke the
 922         ///   compiled expression or statement.
 923         /// </summary>
 924         /// <remarks>
 925         ///   Since the Compile methods will compile
 926         ///   statements and expressions into the same
 927         ///   delegate, you can tell if a value was returned
 928         ///   by checking whether the returned value is of type
 929         ///   NoValueSet.
 930         /// </remarks>
 931
 932         public delegate void CompiledMethod (ref object retvalue);
 933
 934         /// <summary>
 935         ///   The default base class for every interaction line
 936         /// </summary>
 937         /// <remarks>
 938         ///   The expressions and statements behave as if they were
 939         ///   a static method of this class.   The InteractiveBase class
 940         ///   contains a number of useful methods, but can be overwritten
 941         ///   by setting the InteractiveBaseType property in the Evaluator
 942         /// </remarks>
 943         public class InteractiveBase {
 944                 /// <summary>
 945                 ///   Determines where the standard output of methods in this class will go.
 946                 /// </summary>
 947                 public static TextWriter Output = Console.Out;
 948
 949                 /// <summary>
 950                 ///   Determines where the standard error of methods in this class will go.
 951                 /// </summary>
 952                 public static TextWriter Error = Console.Error;
 953
 954                 /// <summary>
 955                 ///   The primary prompt used for interactive use.
 956                 /// </summary>
 957                 public static string Prompt             = "csharp> ";
 958
 959                 /// <summary>
 960                 ///   The secondary prompt used for interactive use (used when
 961                 ///   an expression is incomplete).
 962                 /// </summary>
 963                 public static string ContinuationPrompt = "      > ";
 964
 965                 /// <summary>
 966                 ///   Used to signal that the user has invoked the  `quit' statement.
 967                 /// </summary>
 968                 public static bool QuitRequested;
 969
 970                 /// <summary>
 971                 ///   Shows all the variables defined so far.
 972                 /// </summary>
 973                 static public void ShowVars ()
 974                 {
 975                         Output.Write (Evaluator.GetVars ());
 976                         Output.Flush ();
 977                 }
 978
 979                 /// <summary>
 980                 ///   Displays the using statements in effect at this point.
 981                 /// </summary>
 982                 static public void ShowUsing ()
 983                 {
 984                         Output.Write (Evaluator.GetUsing ());
 985                         Output.Flush ();
 986                 }
 987
 988                 public delegate void Simple ();
 989
 990                 /// <summary>
 991                 ///   Times the execution of the given delegate
 992                 /// </summary>
 993                 static public TimeSpan Time (Simple a)
 994                 {
 995                         DateTime start = DateTime.Now;
 996                         a ();
 997                         return DateTime.Now - start;
 998                 }
 999
1000 #if !STATIC
1001                 /// <summary>
1002                 ///   Loads the assemblies from a package
1003                 /// </summary>
1004                 /// <remarks>
1005                 ///   Loads the assemblies from a package.   This is equivalent
1006                 ///   to passing the -pkg: command line flag to the C# compiler
1007                 ///   on the command line.
1008                 /// </remarks>
1009                 static public void LoadPackage (string pkg)
1010                 {
1011                         if (pkg == null){
1012                                 Error.WriteLine ("Invalid package specified");
1013                                 return;
1014                         }
1015
1016                         string pkgout = Driver.GetPackageFlags (pkg, false, RootContext.ToplevelTypes.Compiler.Report);
1017                         if (pkgout == null)
1018                                 return;
1019
1020                         string [] xargs = pkgout.Trim (new Char [] {' ', '\n', '\r', '\t'}).
1021                                 Split (new Char [] { ' ', '\t'});
1022
1023                         foreach (string s in xargs){
1024                                 if (s.StartsWith ("-r:") || s.StartsWith ("/r:") || s.StartsWith ("/reference:")){
1025                                         string lib = s.Substring (s.IndexOf (':')+1);
1026
1027                                         Evaluator.LoadAssembly (lib);
1028                                         continue;
1029                                 }
1030                         }
1031                 }
1032 #endif
1033
1034 #if !STATIC
1035                 /// <summary>
1036                 ///   Loads the assembly
1037                 /// </summary>
1038                 /// <remarks>
1039                 ///   Loads the specified assembly and makes its types
1040                 ///   available to the evaluator.  This is equivalent
1041                 ///   to passing the -pkg: command line flag to the C#
1042                 ///   compiler on the command line.
1043                 /// </remarks>
1044                 static public void LoadAssembly (string assembly)
1045                 {
1046                         Evaluator.LoadAssembly (assembly);
1047                 }
1048 #endif
1049
1050                 /// <summary>
1051                 ///   Returns a list of available static methods.
1052                 /// </summary>
1053                 static public string help {
1054                         get {
1055                                 return "Static methods:\n" +
1056                                         "  Describe (object)       - Describes the object's type\n" +
1057                                         "  LoadPackage (package);  - Loads the given Package (like -pkg:FILE)\n" +
1058                                         "  LoadAssembly (assembly) - Loads the given assembly (like -r:ASSEMBLY)\n" +
1059                                         "  ShowVars ();            - Shows defined local variables.\n" +
1060                                         "  ShowUsing ();           - Show active using declarations.\n" +
1061                                         "  Prompt                  - The prompt used by the C# shell\n" +
1062                                         "  ContinuationPrompt      - The prompt for partial input\n" +
1063                                         "  Time(() -> { })         - Times the specified code\n" +
1064                                         "  quit;                   - You'll never believe it - this quits the repl!\n" +
1065                                         "  help;                   - This help text\n";
1066                         }
1067                 }
1068
1069                 /// <summary>
1070                 ///   Indicates to the read-eval-print-loop that the interaction should be finished.
1071                 /// </summary>
1072                 static public object quit {
1073                         get {
1074                                 QuitRequested = true;
1075
1076                                 // To avoid print null at the exit
1077                                 return typeof (Evaluator.NoValueSet);
1078                         }
1079                 }
1080
1081 #if !NET_2_1
1082                 /// <summary>
1083                 ///   Describes an object or a type.
1084                 /// </summary>
1085                 /// <remarks>
1086                 ///   This method will show a textual representation
1087                 ///   of the object's type.  If the object is a
1088                 ///   System.Type it renders the type directly,
1089                 ///   otherwise it renders the type returned by
1090                 ///   invoking GetType on the object.
1091                 /// </remarks>
1092                 static public string Describe (object x)
1093                 {
1094                         if (x == null)
1095                                 return "<null>";
1096
1097                         var type = x as Type ?? x.GetType ();
1098
1099                         StringWriter sw = new StringWriter ();
1100                         new Outline (type, sw, true, false, false).OutlineType ();
1101                         return sw.ToString ();
1102                 }
1103 #endif
1104         }
1105
1106         class HoistedEvaluatorVariable : HoistedVariable
1107         {
1108                 public HoistedEvaluatorVariable (Field field)
1109                         : base (null, field)
1110                 {
1111                 }
1112
1113                 public override void EmitSymbolInfo ()
1114                 {
1115                 }
1116
1117                 protected override FieldExpr GetFieldExpression (EmitContext ec)
1118                 {
1119                         return new FieldExpr (field, field.Location);
1120                 }
1121         }
1122
1123         /// <summary>
1124         ///    A class used to assign values if the source expression is not void
1125         ///
1126         ///    Used by the interactive shell to allow it to call this code to set
1127         ///    the return value for an invocation.
1128         /// </summary>
1129         class OptionalAssign : SimpleAssign {
1130                 public OptionalAssign (Expression t, Expression s, Location loc)
1131                         : base (t, s, loc)
1132                 {
1133                 }
1134
1135                 protected override Expression DoResolve (ResolveContext ec)
1136                 {
1137                         CloneContext cc = new CloneContext ();
1138                         Expression clone = source.Clone (cc);
1139
1140                         //
1141                         // A useful feature for the REPL: if we can resolve the expression
1142                         // as a type, Describe the type;
1143                         //
1144                         if (Evaluator.DescribeTypeExpressions){
1145                                 var old_printer = Evaluator.SetPrinter (new StreamReportPrinter (TextWriter.Null));
1146                                 clone = clone.Resolve (ec);
1147                                 if (clone == null){
1148                                         clone = source.Clone (cc);
1149                                         clone = clone.Resolve (ec, ResolveFlags.Type);
1150                                         if (clone == null){
1151                                                 Evaluator.SetPrinter (old_printer);
1152                                                 clone = source.Clone (cc);
1153                                                 clone = clone.Resolve (ec);
1154                                                 return null;
1155                                         }
1156
1157                                         Arguments args = new Arguments (1);
1158                                         args.Add (new Argument (new TypeOf ((TypeExpr) clone, Location)));
1159                                         source = new Invocation (new SimpleName ("Describe", Location), args).Resolve (ec);
1160                                 }
1161                                 Evaluator.SetPrinter (old_printer);
1162                         } else {
1163                                 clone = clone.Resolve (ec);
1164                                 if (clone == null)
1165                                         return null;
1166                         }
1167
1168                         // This means its really a statement.
1169                         if (clone.Type == TypeManager.void_type || clone is DynamicInvocation || clone is Assign) {
1170                                 return clone;
1171                         }
1172
1173                         return base.DoResolve (ec);
1174                 }
1175         }
1176
1177         public class Undo {
1178                 List<KeyValuePair<TypeContainer, TypeContainer>> undo_types;
1179
1180                 public Undo ()
1181                 {
1182                         undo_types = new List<KeyValuePair<TypeContainer, TypeContainer>> ();
1183                 }
1184
1185                 public void AddTypeContainer (TypeContainer current_container, TypeContainer tc)
1186                 {
1187                         if (current_container == tc){
1188                                 Console.Error.WriteLine ("Internal error: inserting container into itself");
1189                                 return;
1190                         }
1191
1192                         if (undo_types == null)
1193                                 undo_types = new List<KeyValuePair<TypeContainer, TypeContainer>> ();
1194
1195                         undo_types.Add (new KeyValuePair<TypeContainer, TypeContainer> (current_container, tc));
1196                 }
1197
1198                 public void ExecuteUndo ()
1199                 {
1200                         if (undo_types == null)
1201                                 return;
1202
1203                         foreach (var p in undo_types){
1204                                 TypeContainer current_container = p.Key;
1205
1206                                 current_container.RemoveTypeContainer (p.Value);
1207                         }
1208                         undo_types = null;
1209                 }
1210         }
1211
1212 }