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