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.Globalization;
  19 using System.Text;
  20
  21 namespace Mono.CSharp {
  22
  23         /// <summary>
  24         ///   Evaluator: provides an API to evaluate C# statements and
  25         ///   expressions dynamically.
  26         /// </summary>
  27         /// <remarks>
  28         ///   This class exposes static methods to evaluate expressions in the
  29         ///   current program.
  30         ///
  31         ///   To initialize the evaluator with a number of compiler
  32         ///   options call the Init(string[]args) method with a set of
  33         ///   command line options that the compiler recognizes.
  34         ///
  35         ///   To interrupt execution of a statement, you can invoke the
  36         ///   Evaluator.Interrupt method.
  37         /// </remarks>
  38         public class Evaluator {
  39
  40                 enum ParseMode {
  41                         // Parse silently, do not output any error messages
  42                         Silent,
  43
  44                         // Report errors during parse
  45                         ReportErrors,
  46
  47                         // Auto-complete, means that the tokenizer will start producing
  48                         // GETCOMPLETIONS tokens when it reaches a certain point.
  49                         GetCompletions
  50                 }
  51
  52                 static object evaluator_lock = new object ();
  53
  54                 static string current_debug_name;
  55                 static int count;
  56                 static Thread invoke_thread;
  57
  58                 static List<NamespaceEntry.UsingAliasEntry> using_alias_list = new List<NamespaceEntry.UsingAliasEntry> ();
  59                 internal static List<NamespaceEntry.UsingEntry> using_list = new List<NamespaceEntry.UsingEntry> ();
  60                 static Dictionary<string, FieldInfo> fields = new Dictionary<string, FieldInfo> ();
  61
  62                 static TypeSpec interactive_base_class;
  63                 static Driver driver;
  64                 static bool inited;
  65
  66                 static CompilerContext ctx;
  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                                 RootContext.ToplevelTypes = new ModuleCompiled (ctx, true);
 121
 122                                 driver.ProcessDefaultConfig ();
 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                                 RootContext.ToplevelTypes = new ModuleCompiled (ctx, true);
 130                                 /*var ctypes = */TypeManager.InitCoreTypes ();
 131                                 TypeManager.InitExpressionTypes ();
 132
 133                                 Import.Initialize ();
 134                                 driver.LoadReferences ();
 135                                 TypeManager.InitOptionalCoreTypes (ctx);
 136
 137                                 RootContext.EvalMode = true;
 138                                 inited = true;
 139
 140                                 return startup_files.ToArray ();
 141                         }
 142                 }
 143
 144                 static void Init ()
 145                 {
 146                         Init (new string [0]);
 147                 }
 148
 149                 static void Reset ()
 150                 {
 151                         CompilerCallableEntryPoint.PartialReset ();
 152                         RootContext.PartialReset ();
 153
 154                         // Workaround for API limitation where full message printer cannot be passed
 155                         ReportPrinter printer;
 156                         if (MessageOutput == Console.Out || MessageOutput == Console.Error){
 157                                 var console_reporter = new ConsoleReportPrinter (MessageOutput);
 158                                 console_reporter.Fatal = driver.fatal_errors;
 159                                 printer = console_reporter;
 160                         } else
 161                                 printer = new StreamReportPrinter (MessageOutput);
 162
 163                         ctx = new CompilerContext (new Report (printer));
 164                         RootContext.ToplevelTypes = new ModuleCompiled (ctx, true);
 165
 166                         //
 167                         // PartialReset should not reset the core types, this is very redundant.
 168                         //
 169 //                      if (!TypeManager.InitCoreTypes (ctx, null))
 170 //                              throw new Exception ("Failed to InitCoreTypes");
 171 //                      TypeManager.InitOptionalCoreTypes (ctx);
 172
 173                         Location.AddFile (null, "{interactive}");
 174                         Location.Initialize ();
 175
 176                         current_debug_name = "interactive" + (count++) + ".dll";
 177                         if (Environment.GetEnvironmentVariable ("SAVE") != null){
 178                                 CodeGen.Init (current_debug_name, current_debug_name, false, ctx);
 179                         } else
 180                                 CodeGen.InitDynamic (ctx, current_debug_name);
 181                 }
 182
 183                 /// <summary>
 184                 ///   The base class for the classes that host the user generated code
 185                 /// </summary>
 186                 /// <remarks>
 187                 ///
 188                 ///   This is the base class that will host the code
 189                 ///   executed by the Evaluator.  By default
 190                 ///   this is the Mono.CSharp.InteractiveBase class
 191                 ///   which is useful for interactive use.
 192                 ///
 193                 ///   By changing this property you can control the
 194                 ///   base class and the static members that are
 195                 ///   available to your evaluated code.
 196                 /// </remarks>
 197                 static public TypeSpec InteractiveBaseClass {
 198                         get {
 199                                 if (interactive_base_class != null)
 200                                         return interactive_base_class;
 201
 202                                 return Import.ImportType (typeof (InteractiveBase));
 203                         }
 204                 }
 205
 206                 public static void SetInteractiveBaseClass (Type type)
 207                 {
 208                         if (type == null)
 209                                 throw new ArgumentNullException ();
 210
 211                         lock (evaluator_lock)
 212                                 interactive_base_class = Import.ImportType (type);
 213                 }
 214
 215                 /// <summary>
 216                 ///   Interrupts the evaluation of an expression executing in Evaluate.
 217                 /// </summary>
 218                 /// <remarks>
 219                 ///   Use this method to interrupt long-running invocations.
 220                 /// </remarks>
 221                 public static void Interrupt ()
 222                 {
 223                         if (!inited || !invoking)
 224                                 return;
 225
 226                         if (invoke_thread != null)
 227                                 invoke_thread.Abort ();
 228                 }
 229
 230                 /// <summary>
 231                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 232                 /// </summary>
 233                 /// <remarks>
 234                 ///
 235                 ///   Compiles the input string as a C# expression or
 236                 ///   statement, unlike the Evaluate method, the
 237                 ///   resulting delegate can be invoked multiple times
 238                 ///   without incurring in the compilation overhead.
 239                 ///
 240                 ///   If the return value of this function is null,
 241                 ///   this indicates that the parsing was complete.
 242                 ///   If the return value is a string it indicates
 243                 ///   that the input string was partial and that the
 244                 ///   invoking code should provide more code before
 245                 ///   the code can be successfully compiled.
 246                 ///
 247                 ///   If you know that you will always get full expressions or
 248                 ///   statements and do not care about partial input, you can use
 249                 ///   the other Compile overload.
 250                 ///
 251                 ///   On success, in addition to returning null, the
 252                 ///   compiled parameter will be set to the delegate
 253                 ///   that can be invoked to execute the code.
 254                 ///
 255                 /// </remarks>
 256                 static public string Compile (string input, out CompiledMethod compiled)
 257                 {
 258                         if (input == null || input.Length == 0){
 259                                 compiled = null;
 260                                 return null;
 261                         }
 262
 263                         lock (evaluator_lock){
 264                                 if (!inited)
 265                                         Init ();
 266
 267                                 bool partial_input;
 268                                 CSharpParser parser = ParseString (ParseMode.Silent, input, out partial_input);
 269                                 if (parser == null){
 270                                         compiled = null;
 271                                         if (partial_input)
 272                                                 return input;
 273
 274                                         ParseString (ParseMode.ReportErrors, input, out partial_input);
 275                                         return null;
 276                                 }
 277
 278                                 object parser_result = parser.InteractiveResult;
 279
 280                                 if (!(parser_result is Class)){
 281                                         int errors = ctx.Report.Errors;
 282
 283                                         NamespaceEntry.VerifyAllUsing ();
 284                                         if (errors == ctx.Report.Errors)
 285                                                 parser.CurrentNamespace.Extract (using_alias_list, using_list);
 286                                 }
 287
 288                                 compiled = CompileBlock (parser_result as Class, parser.undo, ctx.Report);
 289                         }
 290
 291                         return null;
 292                 }
 293
 294                 /// <summary>
 295                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 296                 /// </summary>
 297                 /// <remarks>
 298                 ///
 299                 ///   Compiles the input string as a C# expression or
 300                 ///   statement, unlike the Evaluate method, the
 301                 ///   resulting delegate can be invoked multiple times
 302                 ///   without incurring in the compilation overhead.
 303                 ///
 304                 ///   This method can only deal with fully formed input
 305                 ///   strings and does not provide a completion mechanism.
 306                 ///   If you must deal with partial input (for example for
 307                 ///   interactive use) use the other overload.
 308                 ///
 309                 ///   On success, a delegate is returned that can be used
 310                 ///   to invoke the method.
 311                 ///
 312                 /// </remarks>
 313                 static public CompiledMethod Compile (string input)
 314                 {
 315                         CompiledMethod compiled;
 316
 317                         // Ignore partial inputs
 318                         if (Compile (input, out compiled) != null){
 319                                 // Error, the input was partial.
 320                                 return null;
 321                         }
 322
 323                         // Either null (on error) or the compiled method.
 324                         return compiled;
 325                 }
 326
 327                 //
 328                 // Todo: Should we handle errors, or expect the calling code to setup
 329                 // the recording themselves?
 330                 //
 331
 332                 /// <summary>
 333                 ///   Evaluates and expression or statement and returns any result values.
 334                 /// </summary>
 335                 /// <remarks>
 336                 ///   Evaluates the input string as a C# expression or
 337                 ///   statement.  If the input string is an expression
 338                 ///   the result will be stored in the result variable
 339                 ///   and the result_set variable will be set to true.
 340                 ///
 341                 ///   It is necessary to use the result/result_set
 342                 ///   pair to identify when a result was set (for
 343                 ///   example, execution of user-provided input can be
 344                 ///   an expression, a statement or others, and
 345                 ///   result_set would only be set if the input was an
 346                 ///   expression.
 347                 ///
 348                 ///   If the return value of this function is null,
 349                 ///   this indicates that the parsing was complete.
 350                 ///   If the return value is a string, it indicates
 351                 ///   that the input is partial and that the user
 352                 ///   should provide an updated string.
 353                 /// </remarks>
 354                 public static string Evaluate (string input, out object result, out bool result_set)
 355                 {
 356                         CompiledMethod compiled;
 357
 358                         result_set = false;
 359                         result = null;
 360
 361                         input = Compile (input, out compiled);
 362                         if (input != null)
 363                                 return input;
 364
 365                         if (compiled == null)
 366                                 return null;
 367
 368                         //
 369                         // The code execution does not need to keep the compiler lock
 370                         //
 371                         object retval = typeof (NoValueSet);
 372
 373                         try {
 374                                 invoke_thread = System.Threading.Thread.CurrentThread;
 375                                 invoking = true;
 376                                 compiled (ref retval);
 377                         } catch (ThreadAbortException e){
 378                                 Thread.ResetAbort ();
 379                                 Console.WriteLine ("Interrupted!\n{0}", e);
 380                         } finally {
 381                                 invoking = false;
 382                         }
 383
 384                         //
 385                         // We use a reference to a compiler type, in this case
 386                         // Driver as a flag to indicate that this was a statement
 387                         //
 388                         if (retval != typeof (NoValueSet)){
 389                                 result_set = true;
 390                                 result = retval;
 391                         }
 392
 393                         return null;
 394                 }
 395
 396                 public static string [] GetCompletions (string input, out string prefix)
 397                 {
 398                         prefix = "";
 399                         if (input == null || input.Length == 0)
 400                                 return null;
 401
 402                         lock (evaluator_lock){
 403                                 if (!inited)
 404                                         Init ();
 405
 406                                 bool partial_input;
 407                                 CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
 408                                 if (parser == null){
 409                                         if (CSharpParser.yacc_verbose_flag != 0)
 410                                                 Console.WriteLine ("DEBUG: No completions available");
 411                                         return null;
 412                                 }
 413
 414                                 Class parser_result = parser.InteractiveResult as Class;
 415
 416                                 if (parser_result == null){
 417                                         if (CSharpParser.yacc_verbose_flag != 0)
 418                                                 Console.WriteLine ("Do not know how to cope with !Class yet");
 419                                         return null;
 420                                 }
 421
 422                                 try {
 423                                         RootContext.ResolveTree ();
 424                                         if (ctx.Report.Errors != 0)
 425                                                 return null;
 426
 427                                         RootContext.PopulateTypes ();
 428                                         if (ctx.Report.Errors != 0)
 429                                                 return null;
 430
 431                                         MethodOrOperator method = null;
 432                                         foreach (MemberCore member in parser_result.Methods){
 433                                                 if (member.Name != "Host")
 434                                                         continue;
 435
 436                                                 method = (MethodOrOperator) member;
 437                                                 break;
 438                                         }
 439                                         if (method == null)
 440                                                 throw new InternalErrorException ("did not find the the Host method");
 441
 442                                         BlockContext bc = new BlockContext (method, method.Block, method.ReturnType);
 443
 444                                         try {
 445                                                 method.Block.Resolve (null, bc, method.ParameterInfo, method);
 446                                         } catch (CompletionResult cr){
 447                                                 prefix = cr.BaseText;
 448                                                 return cr.Result;
 449                                         }
 450                                 } finally {
 451                                         parser.undo.ExecuteUndo ();
 452                                 }
 453
 454                         }
 455                         return null;
 456                 }
 457
 458                 /// <summary>
 459                 ///   Executes the given expression or statement.
 460                 /// </summary>
 461                 /// <remarks>
 462                 ///    Executes the provided statement, returns true
 463                 ///    on success, false on parsing errors.  Exceptions
 464                 ///    might be thrown by the called code.
 465                 /// </remarks>
 466                 public static bool Run (string statement)
 467                 {
 468                         if (!inited)
 469                                 Init ();
 470
 471                         object result;
 472                         bool result_set;
 473
 474                         bool ok = Evaluate (statement, out result, out result_set) == null;
 475
 476                         return ok;
 477                 }
 478
 479                 /// <summary>
 480                 ///   Evaluates and expression or statement and returns the result.
 481                 /// </summary>
 482                 /// <remarks>
 483                 ///   Evaluates the input string as a C# expression or
 484                 ///   statement and returns the value.
 485                 ///
 486                 ///   This method will throw an exception if there is a syntax error,
 487                 ///   of if the provided input is not an expression but a statement.
 488                 /// </remarks>
 489                 public static object Evaluate (string input)
 490                 {
 491                         object result;
 492                         bool result_set;
 493
 494                         string r = Evaluate (input, out result, out result_set);
 495
 496                         if (r != null)
 497                                 throw new ArgumentException ("Syntax error on input: partial input");
 498
 499                         if (result_set == false)
 500                                 throw new ArgumentException ("The expression did not set a result");
 501
 502                         return result;
 503                 }
 504
 505                 enum InputKind {
 506                         EOF,
 507                         StatementOrExpression,
 508                         CompilationUnit,
 509                         Error
 510                 }
 511
 512                 //
 513                 // Deambiguates the input string to determine if we
 514                 // want to process a statement or if we want to
 515                 // process a compilation unit.
 516                 //
 517                 // This is done using a top-down predictive parser,
 518                 // since the yacc/jay parser can not deambiguage this
 519                 // without more than one lookahead token.   There are very
 520                 // few ambiguities.
 521                 //
 522                 static InputKind ToplevelOrStatement (SeekableStreamReader seekable)
 523                 {
 524                         Tokenizer tokenizer = new Tokenizer (seekable, (CompilationUnit) Location.SourceFiles [0], ctx);
 525
 526                         int t = tokenizer.token ();
 527                         switch (t){
 528                         case Token.EOF:
 529                                 return InputKind.EOF;
 530
 531                         // These are toplevels
 532                         case Token.EXTERN:
 533                         case Token.OPEN_BRACKET:
 534                         case Token.ABSTRACT:
 535                         case Token.CLASS:
 536                         case Token.ENUM:
 537                         case Token.INTERFACE:
 538                         case Token.INTERNAL:
 539                         case Token.NAMESPACE:
 540                         case Token.PRIVATE:
 541                         case Token.PROTECTED:
 542                         case Token.PUBLIC:
 543                         case Token.SEALED:
 544                         case Token.STATIC:
 545                         case Token.STRUCT:
 546                                 return InputKind.CompilationUnit;
 547
 548                         // Definitely expression
 549                         case Token.FIXED:
 550                         case Token.BOOL:
 551                         case Token.BYTE:
 552                         case Token.CHAR:
 553                         case Token.DECIMAL:
 554                         case Token.DOUBLE:
 555                         case Token.FLOAT:
 556                         case Token.INT:
 557                         case Token.LONG:
 558                         case Token.NEW:
 559                         case Token.OBJECT:
 560                         case Token.SBYTE:
 561                         case Token.SHORT:
 562                         case Token.STRING:
 563                         case Token.UINT:
 564                         case Token.ULONG:
 565                                 return InputKind.StatementOrExpression;
 566
 567                         // These need deambiguation help
 568                         case Token.USING:
 569                                 t = tokenizer.token ();
 570                                 if (t == Token.EOF)
 571                                         return InputKind.EOF;
 572
 573                                 if (t == Token.IDENTIFIER)
 574                                         return InputKind.CompilationUnit;
 575                                 return InputKind.StatementOrExpression;
 576
 577
 578                         // Distinguish between:
 579                         //    delegate opt_anonymous_method_signature block
 580                         //    delegate type
 581                         case Token.DELEGATE:
 582                                 t = tokenizer.token ();
 583                                 if (t == Token.EOF)
 584                                         return InputKind.EOF;
 585                                 if (t == Token.OPEN_PARENS || t == Token.OPEN_BRACE)
 586                                         return InputKind.StatementOrExpression;
 587                                 return InputKind.CompilationUnit;
 588
 589                         // Distinguih between:
 590                         //    unsafe block
 591                         //    unsafe as modifier of a type declaration
 592                         case Token.UNSAFE:
 593                                 t = tokenizer.token ();
 594                                 if (t == Token.EOF)
 595                                         return InputKind.EOF;
 596                                 if (t == Token.OPEN_PARENS)
 597                                         return InputKind.StatementOrExpression;
 598                                 return InputKind.CompilationUnit;
 599
 600                         // These are errors: we list explicitly what we had
 601                         // from the grammar, ERROR and then everything else
 602
 603                         case Token.READONLY:
 604                         case Token.OVERRIDE:
 605                         case Token.ERROR:
 606                                 return InputKind.Error;
 607
 608                         // This catches everything else allowed by
 609                         // expressions.  We could add one-by-one use cases
 610                         // if needed.
 611                         default:
 612                                 return InputKind.StatementOrExpression;
 613                         }
 614                 }
 615
 616                 //
 617                 // Parses the string @input and returns a CSharpParser if succeeful.
 618                 //
 619                 // if @silent is set to true then no errors are
 620                 // reported to the user.  This is used to do various calls to the
 621                 // parser and check if the expression is parsable.
 622                 //
 623                 // @partial_input: if @silent is true, then it returns whether the
 624                 // parsed expression was partial, and more data is needed
 625                 //
 626                 static CSharpParser ParseString (ParseMode mode, string input, out bool partial_input)
 627                 {
 628                         partial_input = false;
 629                         Reset ();
 630                         queued_fields.Clear ();
 631                         Tokenizer.LocatedToken.Initialize ();
 632
 633                         Stream s = new MemoryStream (Encoding.Default.GetBytes (input));
 634                         SeekableStreamReader seekable = new SeekableStreamReader (s, Encoding.Default);
 635
 636                         InputKind kind = ToplevelOrStatement (seekable);
 637                         if (kind == InputKind.Error){
 638                                 if (mode == ParseMode.ReportErrors)
 639                                         ctx.Report.Error (-25, "Detection Parsing Error");
 640                                 partial_input = false;
 641                                 return null;
 642                         }
 643
 644                         if (kind == InputKind.EOF){
 645                                 if (mode == ParseMode.ReportErrors)
 646                                         Console.Error.WriteLine ("Internal error: EOF condition should have been detected in a previous call with silent=true");
 647                                 partial_input = true;
 648                                 return null;
 649
 650                         }
 651                         seekable.Position = 0;
 652
 653                         CSharpParser parser = new CSharpParser (seekable, (CompilationUnit) Location.SourceFiles [0], ctx);
 654
 655                         if (kind == InputKind.StatementOrExpression){
 656                                 parser.Lexer.putback_char = Tokenizer.EvalStatementParserCharacter;
 657                                 RootContext.StatementMode = true;
 658                         } else {
 659                                 //
 660                                 // Do not activate EvalCompilationUnitParserCharacter until
 661                                 // I have figured out all the limitations to invoke methods
 662                                 // in the generated classes.  See repl.txt
 663                                 //
 664                                 parser.Lexer.putback_char = Tokenizer.EvalUsingDeclarationsParserCharacter;
 665                                 //parser.Lexer.putback_char = Tokenizer.EvalCompilationUnitParserCharacter;
 666                                 RootContext.StatementMode = false;
 667                         }
 668
 669                         if (mode == ParseMode.GetCompletions)
 670                                 parser.Lexer.CompleteOnEOF = true;
 671
 672                         ReportPrinter old_printer = null;
 673                         if ((mode == ParseMode.Silent || mode == ParseMode.GetCompletions) && CSharpParser.yacc_verbose_flag == 0)
 674                                 old_printer = SetPrinter (new StreamReportPrinter (TextWriter.Null));
 675
 676                         try {
 677                                 parser.parse ();
 678                         } finally {
 679                                 if (ctx.Report.Errors != 0){
 680                                         if (mode != ParseMode.ReportErrors  && parser.UnexpectedEOF)
 681                                                 partial_input = true;
 682
 683                                         parser.undo.ExecuteUndo ();
 684                                         parser = null;
 685                                 }
 686
 687                                 if (old_printer != null)
 688                                         SetPrinter (old_printer);
 689                         }
 690                         return parser;
 691                 }
 692
 693                 //
 694                 // Queue all the fields that we use, as we need to then go from FieldBuilder to FieldInfo
 695                 // or reflection gets confused (it basically gets confused, and variables override each
 696                 // other).
 697                 //
 698                 static List<Field> queued_fields = new List<Field> ();
 699
 700                 //static ArrayList types = new ArrayList ();
 701
 702                 static volatile bool invoking;
 703
 704                 static CompiledMethod CompileBlock (Class host, Undo undo, Report Report)
 705                 {
 706                         RootContext.ResolveTree ();
 707                         if (Report.Errors != 0){
 708                                 undo.ExecuteUndo ();
 709                                 return null;
 710                         }
 711
 712                         RootContext.PopulateTypes ();
 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.EmitCode ();
 739                         if (Report.Errors != 0){
 740                                 undo.ExecuteUndo ();
 741                                 return null;
 742                         }
 743
 744                         RootContext.CloseTypes ();
 745
 746                         if (Environment.GetEnvironmentVariable ("SAVE") != null)
 747                                 CodeGen.Save (current_debug_name, false, Report);
 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 = CodeGen.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                                 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.FieldType.IsValueType){
 769                                                 //
 770                                                 // TODO: Clear fields for structs
 771                                                 //
 772                                         } else {
 773                                                 try {
 774                                                         old.SetValue (null, null);
 775                                                 } catch {
 776                                                 }
 777                                         }
 778                                 }
 779
 780                                 fields [field.Name] = fi;
 781                         }
 782                         //types.Add (tb);
 783
 784                         queued_fields.Clear ();
 785
 786                         return (CompiledMethod) System.Delegate.CreateDelegate (typeof (CompiledMethod), mi);
 787                 }
 788
 789                 static internal void LoadAliases (NamespaceEntry ns)
 790                 {
 791                         ns.Populate (using_alias_list, using_list);
 792                 }
 793
 794                 /// <summary>
 795                 ///   A sentinel value used to indicate that no value was
 796                 ///   was set by the compiled function.   This is used to
 797                 ///   differentiate between a function not returning a
 798                 ///   value and null.
 799                 /// </summary>
 800                 public class NoValueSet {
 801                 }
 802
 803                 static internal FieldInfo LookupField (string name)
 804                 {
 805                         FieldInfo fi;
 806                         if (!fields.TryGetValue (name, out fi))
 807                                 return null;
 808
 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                                         FieldInfo fi = LookupField (de.Key);
 873                                         object value = null;
 874                                         //bool error = false;
 875
 876                                         try {
 877                                                 if (value == null)
 878                                                         value = "null";
 879                                                 value = fi.GetValue (null);
 880                                                 if (value is string)
 881                                                         value = Quote ((string)value);
 882                                         } catch {
 883                                                 //error = true;
 884                                         }
 885
 886                                         throw new NotImplementedException ("net");
 887                                         //if (error)
 888                                         //    sb.Append (String.Format ("{0} {1} <error reading value>", TypeManager.CSharpName(fi.FieldType), de.Key));
 889                                         //else
 890                                         //    sb.Append (String.Format ("{0} {1} = {2}", TypeManager.CSharpName(fi.FieldType), de.Key, value));
 891                                 }
 892
 893                                 return sb.ToString ();
 894                         }
 895                 }
 896
 897                 /// <summary>
 898                 ///    Loads the given assembly and exposes the API to the user.
 899                 /// </summary>
 900                 static public void LoadAssembly (string file)
 901                 {
 902                         lock (evaluator_lock){
 903                                 driver.LoadAssembly (file, false);
 904                                 GlobalRootNamespace.Instance.ComputeNamespaces (ctx);
 905                         }
 906                 }
 907
 908                 /// <summary>
 909                 ///    Exposes the API of the given assembly to the Evaluator
 910                 /// </summary>
 911                 static public void ReferenceAssembly (Assembly a)
 912                 {
 913                         lock (evaluator_lock){
 914 //                              GlobalRootNamespace.Instance.AddAssemblyReference (a);
 915 //                              GlobalRootNamespace.Instance.ComputeNamespaces (ctx);
 916                                 GlobalRootNamespace.Instance.ImportAssembly (a);
 917                         }
 918                 }
 919
 920                 /// <summary>
 921                 ///   If true, turns type expressions into valid expressions
 922                 ///   and calls the describe method on it
 923                 /// </summary>
 924                 public static bool DescribeTypeExpressions;
 925         }
 926
 927
 928         /// <summary>
 929         ///   A delegate that can be used to invoke the
 930         ///   compiled expression or statement.
 931         /// </summary>
 932         /// <remarks>
 933         ///   Since the Compile methods will compile
 934         ///   statements and expressions into the same
 935         ///   delegate, you can tell if a value was returned
 936         ///   by checking whether the returned value is of type
 937         ///   NoValueSet.
 938         /// </remarks>
 939
 940         public delegate void CompiledMethod (ref object retvalue);
 941
 942         /// <summary>
 943         ///   The default base class for every interaction line
 944         /// </summary>
 945         /// <remarks>
 946         ///   The expressions and statements behave as if they were
 947         ///   a static method of this class.   The InteractiveBase class
 948         ///   contains a number of useful methods, but can be overwritten
 949         ///   by setting the InteractiveBaseType property in the Evaluator
 950         /// </remarks>
 951         public class InteractiveBase {
 952                 /// <summary>
 953                 ///   Determines where the standard output of methods in this class will go.
 954                 /// </summary>
 955                 public static TextWriter Output = Console.Out;
 956
 957                 /// <summary>
 958                 ///   Determines where the standard error of methods in this class will go.
 959                 /// </summary>
 960                 public static TextWriter Error = Console.Error;
 961
 962                 /// <summary>
 963                 ///   The primary prompt used for interactive use.
 964                 /// </summary>
 965                 public static string Prompt             = "csharp> ";
 966
 967                 /// <summary>
 968                 ///   The secondary prompt used for interactive use (used when
 969                 ///   an expression is incomplete).
 970                 /// </summary>
 971                 public static string ContinuationPrompt = "      > ";
 972
 973                 /// <summary>
 974                 ///   Used to signal that the user has invoked the  `quit' statement.
 975                 /// </summary>
 976                 public static bool QuitRequested;
 977
 978                 /// <summary>
 979                 ///   Shows all the variables defined so far.
 980                 /// </summary>
 981                 static public void ShowVars ()
 982                 {
 983                         Output.Write (Evaluator.GetVars ());
 984                         Output.Flush ();
 985                 }
 986
 987                 /// <summary>
 988                 ///   Displays the using statements in effect at this point.
 989                 /// </summary>
 990                 static public void ShowUsing ()
 991                 {
 992                         Output.Write (Evaluator.GetUsing ());
 993                         Output.Flush ();
 994                 }
 995
 996                 public delegate void Simple ();
 997
 998                 /// <summary>
 999                 ///   Times the execution of the given delegate
1000                 /// </summary>
1001                 static public TimeSpan Time (Simple a)
1002                 {
1003                         DateTime start = DateTime.Now;
1004                         a ();
1005                         return DateTime.Now - start;
1006                 }
1007
1008 #if !SMCS_SOURCE
1009                 /// <summary>
1010                 ///   Loads the assemblies from a package
1011                 /// </summary>
1012                 /// <remarks>
1013                 ///   Loads the assemblies from a package.   This is equivalent
1014                 ///   to passing the -pkg: command line flag to the C# compiler
1015                 ///   on the command line.
1016                 /// </remarks>
1017                 static public void LoadPackage (string pkg)
1018                 {
1019                         if (pkg == null){
1020                                 Error.WriteLine ("Invalid package specified");
1021                                 return;
1022                         }
1023
1024                         string pkgout = Driver.GetPackageFlags (pkg, false, RootContext.ToplevelTypes.Compiler.Report);
1025                         if (pkgout == null)
1026                                 return;
1027
1028                         string [] xargs = pkgout.Trim (new Char [] {' ', '\n', '\r', '\t'}).
1029                                 Split (new Char [] { ' ', '\t'});
1030
1031                         foreach (string s in xargs){
1032                                 if (s.StartsWith ("-r:") || s.StartsWith ("/r:") || s.StartsWith ("/reference:")){
1033                                         string lib = s.Substring (s.IndexOf (':')+1);
1034
1035                                         Evaluator.LoadAssembly (lib);
1036                                         continue;
1037                                 }
1038                         }
1039                 }
1040 #endif
1041
1042                 /// <summary>
1043                 ///   Loads the assembly
1044                 /// </summary>
1045                 /// <remarks>
1046                 ///   Loads the specified assembly and makes its types
1047                 ///   available to the evaluator.  This is equivalent
1048                 ///   to passing the -pkg: command line flag to the C#
1049                 ///   compiler on the command line.
1050                 /// </remarks>
1051                 static public void LoadAssembly (string assembly)
1052                 {
1053                         Evaluator.LoadAssembly (assembly);
1054                 }
1055
1056                 /// <summary>
1057                 ///   Returns a list of available static methods.
1058                 /// </summary>
1059                 static public string help {
1060                         get {
1061                                 return  "Static methods:\n"+
1062                                         "  Describe(obj)      - Describes the object's type\n" +
1063                                         "  LoadPackage (pkg); - Loads the given Package (like -pkg:FILE)\n" +
1064                                         "  LoadAssembly (ass) - Loads the given assembly (like -r:ASS)\n" +
1065                                         "  ShowVars ();       - Shows defined local variables.\n" +
1066                                         "  ShowUsing ();      - Show active using decltions.\n" +
1067                                         "  Prompt             - The prompt used by the C# shell\n" +
1068                                         "  ContinuationPrompt - The prompt for partial input\n" +
1069                                         "  Time(() -> { })    - Times the specified code\n" +
1070                                         "  quit;\n" +
1071                                         "  help;\n";
1072                         }
1073                 }
1074
1075                 /// <summary>
1076                 ///   Indicates to the read-eval-print-loop that the interaction should be finished.
1077                 /// </summary>
1078                 static public object quit {
1079                         get {
1080                                 QuitRequested = true;
1081                                 return null;
1082                         }
1083                 }
1084
1085 #if !NET_2_1
1086                 /// <summary>
1087                 ///   Describes an object or a type.
1088                 /// </summary>
1089                 /// <remarks>
1090                 ///   This method will show a textual representation
1091                 ///   of the object's type.  If the object is a
1092                 ///   System.Type it renders the type directly,
1093                 ///   otherwise it renders the type returned by
1094                 ///   invoking GetType on the object.
1095                 /// </remarks>
1096                 static public string Describe (object x)
1097                 {
1098                         if (x == null)
1099                                 return "";
1100
1101                         TypeSpec t = x as TypeSpec;
1102 //                      if (t == null)
1103 //                              t = x.GetType ();
1104
1105                         StringWriter sw = new StringWriter ();
1106                         new Outline (t.GetMetaInfo (), sw, true, false, false).OutlineType ();
1107                         return sw.ToString ();
1108                 }
1109 #endif
1110         }
1111
1112         //
1113         // A local variable reference that will create a Field in a
1114         // Class with the resolved type.  This is necessary so we can
1115         // support "var" as a field type in a class declaration.
1116         //
1117         // We allow LocalVariableReferece to do the heavy lifting, and
1118         // then we insert the field with the resolved type
1119         //
1120         public class LocalVariableReferenceWithClassSideEffect : LocalVariableReference {
1121                 TypeContainer container;
1122                 string name;
1123
1124                 public LocalVariableReferenceWithClassSideEffect (TypeContainer container, string name, Block current_block, string local_variable_id, LocalInfo li, Location loc)
1125                         : base (current_block, local_variable_id, loc, li, false)
1126                 {
1127                         this.container = container;
1128                         this.name = name;
1129                 }
1130
1131                 public override bool Equals (object obj)
1132                 {
1133                         LocalVariableReferenceWithClassSideEffect lvr = obj as LocalVariableReferenceWithClassSideEffect;
1134                         if (lvr == null)
1135                                 return false;
1136
1137                         if (lvr.name != name || lvr.container != container)
1138                                 return false;
1139
1140                         return base.Equals (obj);
1141                 }
1142
1143                 public override int GetHashCode ()
1144                 {
1145                         return name.GetHashCode ();
1146                 }
1147
1148                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
1149                 {
1150                         Expression ret = base.DoResolveLValue (ec, right_side);
1151                         if (ret == null)
1152                                 return null;
1153
1154                         Field f = new Field (container, new TypeExpression (ret.Type, Location),
1155                                              Modifiers.PUBLIC | Modifiers.STATIC,
1156                                              new MemberName (name, Location), null);
1157                         container.AddField (f);
1158                         if (f.Define ())
1159                                 Evaluator.QueueField (f);
1160
1161                         return ret;
1162                 }
1163         }
1164
1165         /// <summary>
1166         ///    A class used to assign values if the source expression is not void
1167         ///
1168         ///    Used by the interactive shell to allow it to call this code to set
1169         ///    the return value for an invocation.
1170         /// </summary>
1171         class OptionalAssign : SimpleAssign {
1172                 public OptionalAssign (Expression t, Expression s, Location loc)
1173                         : base (t, s, loc)
1174                 {
1175                 }
1176
1177                 protected override Expression DoResolve (ResolveContext ec)
1178                 {
1179                         CloneContext cc = new CloneContext ();
1180                         Expression clone = source.Clone (cc);
1181
1182                         //
1183                         // A useful feature for the REPL: if we can resolve the expression
1184                         // as a type, Describe the type;
1185                         //
1186                         if (Evaluator.DescribeTypeExpressions){
1187                                 var old_printer = Evaluator.SetPrinter (new StreamReportPrinter (TextWriter.Null));
1188                                 clone = clone.Resolve (ec);
1189                                 if (clone == null){
1190                                         clone = source.Clone (cc);
1191                                         clone = clone.Resolve (ec, ResolveFlags.Type);
1192                                         if (clone == null){
1193                                                 Evaluator.SetPrinter (old_printer);
1194                                                 clone = source.Clone (cc);
1195                                                 clone = clone.Resolve (ec);
1196                                                 return null;
1197                                         }
1198
1199                                         Arguments args = new Arguments (1);
1200                                         args.Add (new Argument (new TypeOf (source, Location)));
1201                                         source = new Invocation (new SimpleName ("Describe", Location), args).Resolve (ec);
1202                                 }
1203                                 Evaluator.SetPrinter (old_printer);
1204                         } else {
1205                                 clone = clone.Resolve (ec);
1206                                 if (clone == null)
1207                                         return null;
1208                         }
1209
1210                         // This means its really a statement.
1211                         if (clone.Type == TypeManager.void_type){
1212                                 source = source.Resolve (ec);
1213                                 target = null;
1214                                 type = TypeManager.void_type;
1215                                 eclass = ExprClass.Value;
1216                                 return this;
1217                         }
1218
1219                         return base.DoResolve (ec);
1220                 }
1221
1222                 public override void Emit (EmitContext ec)
1223                 {
1224                         if (target == null)
1225                                 source.Emit (ec);
1226                         else
1227                                 base.Emit (ec);
1228                 }
1229
1230                 public override void EmitStatement (EmitContext ec)
1231                 {
1232                         if (target == null)
1233                                 source.Emit (ec);
1234                         else
1235                                 base.EmitStatement (ec);
1236                 }
1237         }
1238
1239         public class Undo {
1240                 List<KeyValuePair<TypeContainer, TypeContainer>> undo_types;
1241
1242                 public Undo ()
1243                 {
1244                         undo_types = new List<KeyValuePair<TypeContainer, TypeContainer>> ();
1245                 }
1246
1247                 public void AddTypeContainer (TypeContainer current_container, TypeContainer tc)
1248                 {
1249                         if (current_container == tc){
1250                                 Console.Error.WriteLine ("Internal error: inserting container into itself");
1251                                 return;
1252                         }
1253
1254                         if (undo_types == null)
1255                                 undo_types = new List<KeyValuePair<TypeContainer, TypeContainer>> ();
1256
1257                         undo_types.Add (new KeyValuePair<TypeContainer, TypeContainer> (current_container, tc));
1258                 }
1259
1260                 public void ExecuteUndo ()
1261                 {
1262                         if (undo_types == null)
1263                                 return;
1264
1265                         foreach (var p in undo_types){
1266                                 TypeContainer current_container = p.Key;
1267
1268                                 current_container.RemoveTypeContainer (p.Value);
1269                         }
1270                         undo_types = null;
1271                 }
1272         }
1273
1274 }
1275