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, Tuple<FieldSpec, FieldInfo>> fields = new Dictionary<string, Tuple<FieldSpec, 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
 132                                 Import.Initialize ();
 133                                 driver.LoadReferences ();
 134                                 TypeManager.InitOptionalCoreTypes (ctx);
 135
 136                                 RootContext.EvalMode = true;
 137                                 inited = true;
 138
 139                                 return startup_files.ToArray ();
 140                         }
 141                 }
 142
 143                 static void Init ()
 144                 {
 145                         Init (new string [0]);
 146                 }
 147
 148                 static void Reset ()
 149                 {
 150                         CompilerCallableEntryPoint.PartialReset ();
 151                         RootContext.PartialReset ();
 152
 153                         // Workaround for API limitation where full message printer cannot be passed
 154                         ReportPrinter printer;
 155                         if (MessageOutput == Console.Out || MessageOutput == Console.Error){
 156                                 var console_reporter = new ConsoleReportPrinter (MessageOutput);
 157                                 console_reporter.Fatal = driver.fatal_errors;
 158                                 printer = console_reporter;
 159                         } else
 160                                 printer = new StreamReportPrinter (MessageOutput);
 161
 162                         ctx = new CompilerContext (new Report (printer));
 163                         RootContext.ToplevelTypes = new ModuleCompiled (ctx, true);
 164
 165                         //
 166                         // PartialReset should not reset the core types, this is very redundant.
 167                         //
 168 //                      if (!TypeManager.InitCoreTypes (ctx, null))
 169 //                              throw new Exception ("Failed to InitCoreTypes");
 170 //                      TypeManager.InitOptionalCoreTypes (ctx);
 171
 172                         Location.AddFile (null, "{interactive}");
 173                         Location.Initialize ();
 174
 175                         current_debug_name = "interactive" + (count++) + ".dll";
 176                         if (Environment.GetEnvironmentVariable ("SAVE") != null){
 177                                 CodeGen.Init (current_debug_name, current_debug_name, false, ctx);
 178                         } else
 179                                 CodeGen.InitDynamic (ctx, current_debug_name);
 180                 }
 181
 182                 /// <summary>
 183                 ///   The base class for the classes that host the user generated code
 184                 /// </summary>
 185                 /// <remarks>
 186                 ///
 187                 ///   This is the base class that will host the code
 188                 ///   executed by the Evaluator.  By default
 189                 ///   this is the Mono.CSharp.InteractiveBase class
 190                 ///   which is useful for interactive use.
 191                 ///
 192                 ///   By changing this property you can control the
 193                 ///   base class and the static members that are
 194                 ///   available to your evaluated code.
 195                 /// </remarks>
 196                 static public TypeSpec InteractiveBaseClass {
 197                         get {
 198                                 if (interactive_base_class != null)
 199                                         return interactive_base_class;
 200
 201                                 return Import.ImportType (typeof (InteractiveBase));
 202                         }
 203                 }
 204
 205                 public static void SetInteractiveBaseClass (Type type)
 206                 {
 207                         if (type == null)
 208                                 throw new ArgumentNullException ();
 209
 210                         lock (evaluator_lock)
 211                                 interactive_base_class = Import.ImportType (type);
 212                 }
 213
 214                 /// <summary>
 215                 ///   Interrupts the evaluation of an expression executing in Evaluate.
 216                 /// </summary>
 217                 /// <remarks>
 218                 ///   Use this method to interrupt long-running invocations.
 219                 /// </remarks>
 220                 public static void Interrupt ()
 221                 {
 222                         if (!inited || !invoking)
 223                                 return;
 224
 225                         if (invoke_thread != null)
 226                                 invoke_thread.Abort ();
 227                 }
 228
 229                 /// <summary>
 230                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 231                 /// </summary>
 232                 /// <remarks>
 233                 ///
 234                 ///   Compiles the input string as a C# expression or
 235                 ///   statement, unlike the Evaluate method, the
 236                 ///   resulting delegate can be invoked multiple times
 237                 ///   without incurring in the compilation overhead.
 238                 ///
 239                 ///   If the return value of this function is null,
 240                 ///   this indicates that the parsing was complete.
 241                 ///   If the return value is a string it indicates
 242                 ///   that the input string was partial and that the
 243                 ///   invoking code should provide more code before
 244                 ///   the code can be successfully compiled.
 245                 ///
 246                 ///   If you know that you will always get full expressions or
 247                 ///   statements and do not care about partial input, you can use
 248                 ///   the other Compile overload.
 249                 ///
 250                 ///   On success, in addition to returning null, the
 251                 ///   compiled parameter will be set to the delegate
 252                 ///   that can be invoked to execute the code.
 253                 ///
 254                 /// </remarks>
 255                 static public string Compile (string input, out CompiledMethod compiled)
 256                 {
 257                         if (input == null || input.Length == 0){
 258                                 compiled = null;
 259                                 return null;
 260                         }
 261
 262                         lock (evaluator_lock){
 263                                 if (!inited)
 264                                         Init ();
 265
 266                                 bool partial_input;
 267                                 CSharpParser parser = ParseString (ParseMode.Silent, input, out partial_input);
 268                                 if (parser == null){
 269                                         compiled = null;
 270                                         if (partial_input)
 271                                                 return input;
 272
 273                                         ParseString (ParseMode.ReportErrors, input, out partial_input);
 274                                         return null;
 275                                 }
 276
 277                                 object parser_result = parser.InteractiveResult;
 278
 279                                 if (!(parser_result is Class)){
 280                                         int errors = ctx.Report.Errors;
 281
 282                                         NamespaceEntry.VerifyAllUsing ();
 283                                         if (errors == ctx.Report.Errors)
 284                                                 parser.CurrentNamespace.Extract (using_alias_list, using_list);
 285                                 }
 286
 287                                 compiled = CompileBlock (parser_result as Class, parser.undo, ctx.Report);
 288                         }
 289
 290                         return null;
 291                 }
 292
 293                 /// <summary>
 294                 ///   Compiles the input string and returns a delegate that represents the compiled code.
 295                 /// </summary>
 296                 /// <remarks>
 297                 ///
 298                 ///   Compiles the input string as a C# expression or
 299                 ///   statement, unlike the Evaluate method, the
 300                 ///   resulting delegate can be invoked multiple times
 301                 ///   without incurring in the compilation overhead.
 302                 ///
 303                 ///   This method can only deal with fully formed input
 304                 ///   strings and does not provide a completion mechanism.
 305                 ///   If you must deal with partial input (for example for
 306                 ///   interactive use) use the other overload.
 307                 ///
 308                 ///   On success, a delegate is returned that can be used
 309                 ///   to invoke the method.
 310                 ///
 311                 /// </remarks>
 312                 static public CompiledMethod Compile (string input)
 313                 {
 314                         CompiledMethod compiled;
 315
 316                         // Ignore partial inputs
 317                         if (Compile (input, out compiled) != null){
 318                                 // Error, the input was partial.
 319                                 return null;
 320                         }
 321
 322                         // Either null (on error) or the compiled method.
 323                         return compiled;
 324                 }
 325
 326                 //
 327                 // Todo: Should we handle errors, or expect the calling code to setup
 328                 // the recording themselves?
 329                 //
 330
 331                 /// <summary>
 332                 ///   Evaluates and expression or statement and returns any result values.
 333                 /// </summary>
 334                 /// <remarks>
 335                 ///   Evaluates the input string as a C# expression or
 336                 ///   statement.  If the input string is an expression
 337                 ///   the result will be stored in the result variable
 338                 ///   and the result_set variable will be set to true.
 339                 ///
 340                 ///   It is necessary to use the result/result_set
 341                 ///   pair to identify when a result was set (for
 342                 ///   example, execution of user-provided input can be
 343                 ///   an expression, a statement or others, and
 344                 ///   result_set would only be set if the input was an
 345                 ///   expression.
 346                 ///
 347                 ///   If the return value of this function is null,
 348                 ///   this indicates that the parsing was complete.
 349                 ///   If the return value is a string, it indicates
 350                 ///   that the input is partial and that the user
 351                 ///   should provide an updated string.
 352                 /// </remarks>
 353                 public static string Evaluate (string input, out object result, out bool result_set)
 354                 {
 355                         CompiledMethod compiled;
 356
 357                         result_set = false;
 358                         result = null;
 359
 360                         input = Compile (input, out compiled);
 361                         if (input != null)
 362                                 return input;
 363
 364                         if (compiled == null)
 365                                 return null;
 366
 367                         //
 368                         // The code execution does not need to keep the compiler lock
 369                         //
 370                         object retval = typeof (NoValueSet);
 371
 372                         try {
 373                                 invoke_thread = System.Threading.Thread.CurrentThread;
 374                                 invoking = true;
 375                                 compiled (ref retval);
 376                         } catch (ThreadAbortException e){
 377                                 Thread.ResetAbort ();
 378                                 Console.WriteLine ("Interrupted!\n{0}", e);
 379                         } finally {
 380                                 invoking = false;
 381                         }
 382
 383                         //
 384                         // We use a reference to a compiler type, in this case
 385                         // Driver as a flag to indicate that this was a statement
 386                         //
 387                         if (retval != typeof (NoValueSet)){
 388                                 result_set = true;
 389                                 result = retval;
 390                         }
 391
 392                         return null;
 393                 }
 394
 395                 public static string [] GetCompletions (string input, out string prefix)
 396                 {
 397                         prefix = "";
 398                         if (input == null || input.Length == 0)
 399                                 return null;
 400
 401                         lock (evaluator_lock){
 402                                 if (!inited)
 403                                         Init ();
 404
 405                                 bool partial_input;
 406                                 CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
 407                                 if (parser == null){
 408                                         if (CSharpParser.yacc_verbose_flag != 0)
 409                                                 Console.WriteLine ("DEBUG: No completions available");
 410                                         return null;
 411                                 }
 412
 413                                 Class parser_result = parser.InteractiveResult as Class;
 414
 415                                 if (parser_result == null){
 416                                         if (CSharpParser.yacc_verbose_flag != 0)
 417                                                 Console.WriteLine ("Do not know how to cope with !Class yet");
 418                                         return null;
 419                                 }
 420
 421                                 try {
 422                                         RootContext.ResolveTree ();
 423                                         if (ctx.Report.Errors != 0)
 424                                                 return null;
 425
 426                                         RootContext.PopulateTypes ();
 427                                         if (ctx.Report.Errors != 0)
 428                                                 return null;
 429
 430                                         MethodOrOperator method = null;
 431                                         foreach (MemberCore member in parser_result.Methods){
 432                                                 if (member.Name != "Host")
 433                                                         continue;
 434
 435                                                 method = (MethodOrOperator) member;
 436                                                 break;
 437                                         }
 438                                         if (method == null)
 439                                                 throw new InternalErrorException ("did not find the the Host method");
 440
 441                                         BlockContext bc = new BlockContext (method, method.Block, method.ReturnType);
 442
 443                                         try {
 444                                                 method.Block.Resolve (null, bc, method.ParameterInfo, method);
 445                                         } catch (CompletionResult cr){
 446                                                 prefix = cr.BaseText;
 447                                                 return cr.Result;
 448                                         }
 449                                 } finally {
 450                                         parser.undo.ExecuteUndo ();
 451                                 }
 452
 453                         }
 454                         return null;
 455                 }
 456
 457                 /// <summary>
 458                 ///   Executes the given expression or statement.
 459                 /// </summary>
 460                 /// <remarks>
 461                 ///    Executes the provided statement, returns true
 462                 ///    on success, false on parsing errors.  Exceptions
 463                 ///    might be thrown by the called code.
 464                 /// </remarks>
 465                 public static bool Run (string statement)
 466                 {
 467                         if (!inited)
 468                                 Init ();
 469
 470                         object result;
 471                         bool result_set;
 472
 473                         bool ok = Evaluate (statement, out result, out result_set) == null;
 474
 475                         return ok;
 476                 }
 477
 478                 /// <summary>
 479                 ///   Evaluates and expression or statement and returns the result.
 480                 /// </summary>
 481                 /// <remarks>
 482                 ///   Evaluates the input string as a C# expression or
 483                 ///   statement and returns the value.
 484                 ///
 485                 ///   This method will throw an exception if there is a syntax error,
 486                 ///   of if the provided input is not an expression but a statement.
 487                 /// </remarks>
 488                 public static object Evaluate (string input)
 489                 {
 490                         object result;
 491                         bool result_set;
 492
 493                         string r = Evaluate (input, out result, out result_set);
 494
 495                         if (r != null)
 496                                 throw new ArgumentException ("Syntax error on input: partial input");
 497
 498                         if (result_set == false)
 499                                 throw new ArgumentException ("The expression did not set a result");
 500
 501                         return result;
 502                 }
 503
 504                 enum InputKind {
 505                         EOF,
 506                         StatementOrExpression,
 507                         CompilationUnit,
 508                         Error
 509                 }
 510
 511                 //
 512                 // Deambiguates the input string to determine if we
 513                 // want to process a statement or if we want to
 514                 // process a compilation unit.
 515                 //
 516                 // This is done using a top-down predictive parser,
 517                 // since the yacc/jay parser can not deambiguage this
 518                 // without more than one lookahead token.   There are very
 519                 // few ambiguities.
 520                 //
 521                 static InputKind ToplevelOrStatement (SeekableStreamReader seekable)
 522                 {
 523                         Tokenizer tokenizer = new Tokenizer (seekable, (CompilationUnit) Location.SourceFiles [0], ctx);
 524
 525                         int t = tokenizer.token ();
 526                         switch (t){
 527                         case Token.EOF:
 528                                 return InputKind.EOF;
 529
 530                         // These are toplevels
 531                         case Token.EXTERN:
 532                         case Token.OPEN_BRACKET:
 533                         case Token.ABSTRACT:
 534                         case Token.CLASS:
 535                         case Token.ENUM:
 536                         case Token.INTERFACE:
 537                         case Token.INTERNAL:
 538                         case Token.NAMESPACE:
 539                         case Token.PRIVATE:
 540                         case Token.PROTECTED:
 541                         case Token.PUBLIC:
 542                         case Token.SEALED:
 543                         case Token.STATIC:
 544                         case Token.STRUCT:
 545                                 return InputKind.CompilationUnit;
 546
 547                         // Definitely expression
 548                         case Token.FIXED:
 549                         case Token.BOOL:
 550                         case Token.BYTE:
 551                         case Token.CHAR:
 552                         case Token.DECIMAL:
 553                         case Token.DOUBLE:
 554                         case Token.FLOAT:
 555                         case Token.INT:
 556                         case Token.LONG:
 557                         case Token.NEW:
 558                         case Token.OBJECT:
 559                         case Token.SBYTE:
 560                         case Token.SHORT:
 561                         case Token.STRING:
 562                         case Token.UINT:
 563                         case Token.ULONG:
 564                                 return InputKind.StatementOrExpression;
 565
 566                         // These need deambiguation help
 567                         case Token.USING:
 568                                 t = tokenizer.token ();
 569                                 if (t == Token.EOF)
 570                                         return InputKind.EOF;
 571
 572                                 if (t == Token.IDENTIFIER)
 573                                         return InputKind.CompilationUnit;
 574                                 return InputKind.StatementOrExpression;
 575
 576
 577                         // Distinguish between:
 578                         //    delegate opt_anonymous_method_signature block
 579                         //    delegate type
 580                         case Token.DELEGATE:
 581                                 t = tokenizer.token ();
 582                                 if (t == Token.EOF)
 583                                         return InputKind.EOF;
 584                                 if (t == Token.OPEN_PARENS || t == Token.OPEN_BRACE)
 585                                         return InputKind.StatementOrExpression;
 586                                 return InputKind.CompilationUnit;
 587
 588                         // Distinguih between:
 589                         //    unsafe block
 590                         //    unsafe as modifier of a type declaration
 591                         case Token.UNSAFE:
 592                                 t = tokenizer.token ();
 593                                 if (t == Token.EOF)
 594                                         return InputKind.EOF;
 595                                 if (t == Token.OPEN_PARENS)
 596                                         return InputKind.StatementOrExpression;
 597                                 return InputKind.CompilationUnit;
 598
 599                         // These are errors: we list explicitly what we had
 600                         // from the grammar, ERROR and then everything else
 601
 602                         case Token.READONLY:
 603                         case Token.OVERRIDE:
 604                         case Token.ERROR:
 605                                 return InputKind.Error;
 606
 607                         // This catches everything else allowed by
 608                         // expressions.  We could add one-by-one use cases
 609                         // if needed.
 610                         default:
 611                                 return InputKind.StatementOrExpression;
 612                         }
 613                 }
 614
 615                 //
 616                 // Parses the string @input and returns a CSharpParser if succeeful.
 617                 //
 618                 // if @silent is set to true then no errors are
 619                 // reported to the user.  This is used to do various calls to the
 620                 // parser and check if the expression is parsable.
 621                 //
 622                 // @partial_input: if @silent is true, then it returns whether the
 623                 // parsed expression was partial, and more data is needed
 624                 //
 625                 static CSharpParser ParseString (ParseMode mode, string input, out bool partial_input)
 626                 {
 627                         partial_input = false;
 628                         Reset ();
 629                         queued_fields.Clear ();
 630                         Tokenizer.LocatedToken.Initialize ();
 631
 632                         Stream s = new MemoryStream (Encoding.Default.GetBytes (input));
 633                         SeekableStreamReader seekable = new SeekableStreamReader (s, Encoding.Default);
 634
 635                         InputKind kind = ToplevelOrStatement (seekable);
 636                         if (kind == InputKind.Error){
 637                                 if (mode == ParseMode.ReportErrors)
 638                                         ctx.Report.Error (-25, "Detection Parsing Error");
 639                                 partial_input = false;
 640                                 return null;
 641                         }
 642
 643                         if (kind == InputKind.EOF){
 644                                 if (mode == ParseMode.ReportErrors)
 645                                         Console.Error.WriteLine ("Internal error: EOF condition should have been detected in a previous call with silent=true");
 646                                 partial_input = true;
 647                                 return null;
 648
 649                         }
 650                         seekable.Position = 0;
 651
 652                         CSharpParser parser = new CSharpParser (seekable, (CompilationUnit) Location.SourceFiles [0], ctx);
 653
 654                         if (kind == InputKind.StatementOrExpression){
 655                                 parser.Lexer.putback_char = Tokenizer.EvalStatementParserCharacter;
 656                                 RootContext.StatementMode = true;
 657                         } else {
 658                                 //
 659                                 // Do not activate EvalCompilationUnitParserCharacter until
 660                                 // I have figured out all the limitations to invoke methods
 661                                 // in the generated classes.  See repl.txt
 662                                 //
 663                                 parser.Lexer.putback_char = Tokenizer.EvalUsingDeclarationsParserCharacter;
 664                                 //parser.Lexer.putback_char = Tokenizer.EvalCompilationUnitParserCharacter;
 665                                 RootContext.StatementMode = false;
 666                         }
 667
 668                         if (mode == ParseMode.GetCompletions)
 669                                 parser.Lexer.CompleteOnEOF = true;
 670
 671                         ReportPrinter old_printer = null;
 672                         if ((mode == ParseMode.Silent || mode == ParseMode.GetCompletions) && CSharpParser.yacc_verbose_flag == 0)
 673                                 old_printer = SetPrinter (new StreamReportPrinter (TextWriter.Null));
 674
 675                         try {
 676                                 parser.parse ();
 677                         } finally {
 678                                 if (ctx.Report.Errors != 0){
 679                                         if (mode != ParseMode.ReportErrors  && parser.UnexpectedEOF)
 680                                                 partial_input = true;
 681
 682                                         parser.undo.ExecuteUndo ();
 683                                         parser = null;
 684                                 }
 685
 686                                 if (old_printer != null)
 687                                         SetPrinter (old_printer);
 688                         }
 689                         return parser;
 690                 }
 691
 692                 //
 693                 // Queue all the fields that we use, as we need to then go from FieldBuilder to FieldInfo
 694                 // or reflection gets confused (it basically gets confused, and variables override each
 695                 // other).
 696                 //
 697                 static List<Field> queued_fields = new List<Field> ();
 698
 699                 //static ArrayList types = new ArrayList ();
 700
 701                 static volatile bool invoking;
 702
 703                 static CompiledMethod CompileBlock (Class host, Undo undo, Report Report)
 704                 {
 705                         RootContext.ResolveTree ();
 706                         if (Report.Errors != 0){
 707                                 undo.ExecuteUndo ();
 708                                 return null;
 709                         }
 710
 711                         RootContext.PopulateTypes ();
 712
 713                         if (Report.Errors != 0){
 714                                 undo.ExecuteUndo ();
 715                                 return null;
 716                         }
 717
 718                         TypeBuilder tb = null;
 719                         MethodBuilder mb = null;
 720
 721                         if (host != null){
 722                                 tb = host.TypeBuilder;
 723                                 mb = null;
 724                                 foreach (MemberCore member in host.Methods){
 725                                         if (member.Name != "Host")
 726                                                 continue;
 727
 728                                         MethodOrOperator method = (MethodOrOperator) member;
 729                                         mb = method.MethodBuilder;
 730                                         break;
 731                                 }
 732
 733                                 if (mb == null)
 734                                         throw new Exception ("Internal error: did not find the method builder for the generated method");
 735                         }
 736
 737                         RootContext.EmitCode ();
 738                         if (Report.Errors != 0){
 739                                 undo.ExecuteUndo ();
 740                                 return null;
 741                         }
 742
 743                         RootContext.CloseTypes ();
 744
 745                         if (Environment.GetEnvironmentVariable ("SAVE") != null)
 746                                 CodeGen.Save (current_debug_name, false, Report);
 747
 748                         if (host == null)
 749                                 return null;
 750
 751                         //
 752                         // Unlike Mono, .NET requires that the MethodInfo is fetched, it cant
 753                         // work from MethodBuilders.   Retarded, I know.
 754                         //
 755                         var tt = CodeGen.Assembly.Builder.GetType (tb.Name);
 756                         MethodInfo mi = tt.GetMethod (mb.Name);
 757
 758                         // Pull the FieldInfos from the type, and keep track of them
 759                         foreach (Field field in queued_fields){
 760                                 FieldInfo fi = tt.GetField (field.Name);
 761
 762                                 Tuple<FieldSpec, FieldInfo> old;
 763
 764                                 // If a previous value was set, nullify it, so that we do
 765                                 // not leak memory
 766                                 if (fields.TryGetValue (field.Name, out old)) {
 767                                         if (old.Item1.MemberType.IsStruct) {
 768                                                 //
 769                                                 // TODO: Clear fields for structs
 770                                                 //
 771                                         } else {
 772                                                 try {
 773                                                         old.Item2.SetValue (null, null);
 774                                                 } catch {
 775                                                 }
 776                                         }
 777
 778                                         fields [field.Name] = Tuple.Create (old.Item1, fi);
 779                                 } else {
 780                                         fields.Add (field.Name, Tuple.Create (field.Spec, fi));
 781                                 }
 782                         }
 783                         //types.Add (tb);
 784
 785                         queued_fields.Clear ();
 786
 787                         return (CompiledMethod) System.Delegate.CreateDelegate (typeof (CompiledMethod), mi);
 788                 }
 789
 790                 static internal void LoadAliases (NamespaceEntry ns)
 791                 {
 792                         ns.Populate (using_alias_list, using_list);
 793                 }
 794
 795                 /// <summary>
 796                 ///   A sentinel value used to indicate that no value was
 797                 ///   was set by the compiled function.   This is used to
 798                 ///   differentiate between a function not returning a
 799                 ///   value and null.
 800                 /// </summary>
 801                 public class NoValueSet {
 802                 }
 803
 804                 static internal Tuple<FieldSpec, FieldInfo> LookupField (string name)
 805                 {
 806                         Tuple<FieldSpec, FieldInfo> fi;
 807                         fields.TryGetValue (name, out fi);
 808                         return fi;
 809                 }
 810
 811                 //
 812                 // Puts the FieldBuilder into a queue of names that will be
 813                 // registered.   We can not register FieldBuilders directly
 814                 // we need to fetch the FieldInfo after Reflection cooks the
 815                 // types, or bad things happen (bad means: FieldBuilders behave
 816                 // incorrectly across multiple assemblies, causing assignments to
 817                 // invalid areas
 818                 //
 819                 // This also serves for the parser to register Field classes
 820                 // that should be exposed as global variables
 821                 //
 822                 static internal void QueueField (Field f)
 823                 {
 824                         queued_fields.Add (f);
 825                 }
 826
 827                 static string Quote (string s)
 828                 {
 829                         if (s.IndexOf ('"') != -1)
 830                                 s = s.Replace ("\"", "\\\"");
 831
 832                         return "\"" + s + "\"";
 833                 }
 834
 835                 static public string GetUsing ()
 836                 {
 837                         lock (evaluator_lock){
 838                                 StringBuilder sb = new StringBuilder ();
 839
 840                                 foreach (object x in using_alias_list)
 841                                         sb.Append (String.Format ("using {0};\n", x));
 842
 843                                 foreach (object x in using_list)
 844                                         sb.Append (String.Format ("using {0};\n", x));
 845
 846                                 return sb.ToString ();
 847                         }
 848                 }
 849
 850                 static internal ICollection<string> GetUsingList ()
 851                 {
 852                         var res = new List<string> (using_list.Count);
 853                         foreach (object ue in using_list)
 854                                 res.Add (ue.ToString ());
 855                         return res;
 856                 }
 857
 858                 static internal string [] GetVarNames ()
 859                 {
 860                         lock (evaluator_lock){
 861                                 return new List<string> (fields.Keys).ToArray ();
 862                         }
 863                 }
 864
 865                 static public string GetVars ()
 866                 {
 867                         lock (evaluator_lock){
 868                                 StringBuilder sb = new StringBuilder ();
 869
 870                                 foreach (var de in fields){
 871                                         var fi = LookupField (de.Key);
 872                                         object value;
 873                                         try {
 874                                                 value = fi.Item2.GetValue (null);
 875                                                 if (value is string)
 876                                                         value = Quote ((string)value);
 877                                         } catch {
 878                                                 value = "<error reading value>";
 879                                         }
 880
 881                                         sb.AppendFormat ("{0} {1} = {2}", fi.Item1.MemberType.GetSignatureForError (), de.Key, value);
 882                                         sb.AppendLine ();
 883                                 }
 884
 885                                 return sb.ToString ();
 886                         }
 887                 }
 888
 889                 /// <summary>
 890                 ///    Loads the given assembly and exposes the API to the user.
 891                 /// </summary>
 892                 static public void LoadAssembly (string file)
 893                 {
 894                         lock (evaluator_lock){
 895                                 driver.LoadAssembly (file, false);
 896                                 GlobalRootNamespace.Instance.ComputeNamespaces (ctx);
 897                         }
 898                 }
 899
 900                 /// <summary>
 901                 ///    Exposes the API of the given assembly to the Evaluator
 902                 /// </summary>
 903                 static public void ReferenceAssembly (Assembly a)
 904                 {
 905                         lock (evaluator_lock){
 906 //                              GlobalRootNamespace.Instance.AddAssemblyReference (a);
 907 //                              GlobalRootNamespace.Instance.ComputeNamespaces (ctx);
 908                                 GlobalRootNamespace.Instance.ImportAssembly (a);
 909                         }
 910                 }
 911
 912                 /// <summary>
 913                 ///   If true, turns type expressions into valid expressions
 914                 ///   and calls the describe method on it
 915                 /// </summary>
 916                 public static bool DescribeTypeExpressions;
 917         }
 918
 919
 920         /// <summary>
 921         ///   A delegate that can be used to invoke the
 922         ///   compiled expression or statement.
 923         /// </summary>
 924         /// <remarks>
 925         ///   Since the Compile methods will compile
 926         ///   statements and expressions into the same
 927         ///   delegate, you can tell if a value was returned
 928         ///   by checking whether the returned value is of type
 929         ///   NoValueSet.
 930         /// </remarks>
 931
 932         public delegate void CompiledMethod (ref object retvalue);
 933
 934         /// <summary>
 935         ///   The default base class for every interaction line
 936         /// </summary>
 937         /// <remarks>
 938         ///   The expressions and statements behave as if they were
 939         ///   a static method of this class.   The InteractiveBase class
 940         ///   contains a number of useful methods, but can be overwritten
 941         ///   by setting the InteractiveBaseType property in the Evaluator
 942         /// </remarks>
 943         public class InteractiveBase {
 944                 /// <summary>
 945                 ///   Determines where the standard output of methods in this class will go.
 946                 /// </summary>
 947                 public static TextWriter Output = Console.Out;
 948
 949                 /// <summary>
 950                 ///   Determines where the standard error of methods in this class will go.
 951                 /// </summary>
 952                 public static TextWriter Error = Console.Error;
 953
 954                 /// <summary>
 955                 ///   The primary prompt used for interactive use.
 956                 /// </summary>
 957                 public static string Prompt             = "csharp> ";
 958
 959                 /// <summary>
 960                 ///   The secondary prompt used for interactive use (used when
 961                 ///   an expression is incomplete).
 962                 /// </summary>
 963                 public static string ContinuationPrompt = "      > ";
 964
 965                 /// <summary>
 966                 ///   Used to signal that the user has invoked the  `quit' statement.
 967                 /// </summary>
 968                 public static bool QuitRequested;
 969
 970                 /// <summary>
 971                 ///   Shows all the variables defined so far.
 972                 /// </summary>
 973                 static public void ShowVars ()
 974                 {
 975                         Output.Write (Evaluator.GetVars ());
 976                         Output.Flush ();
 977                 }
 978
 979                 /// <summary>
 980                 ///   Displays the using statements in effect at this point.
 981                 /// </summary>
 982                 static public void ShowUsing ()
 983                 {
 984                         Output.Write (Evaluator.GetUsing ());
 985                         Output.Flush ();
 986                 }
 987
 988                 public delegate void Simple ();
 989
 990                 /// <summary>
 991                 ///   Times the execution of the given delegate
 992                 /// </summary>
 993                 static public TimeSpan Time (Simple a)
 994                 {
 995                         DateTime start = DateTime.Now;
 996                         a ();
 997                         return DateTime.Now - start;
 998                 }
 999
1000 #if !SMCS_SOURCE
1001                 /// <summary>
1002                 ///   Loads the assemblies from a package
1003                 /// </summary>
1004                 /// <remarks>
1005                 ///   Loads the assemblies from a package.   This is equivalent
1006                 ///   to passing the -pkg: command line flag to the C# compiler
1007                 ///   on the command line.
1008                 /// </remarks>
1009                 static public void LoadPackage (string pkg)
1010                 {
1011                         if (pkg == null){
1012                                 Error.WriteLine ("Invalid package specified");
1013                                 return;
1014                         }
1015
1016                         string pkgout = Driver.GetPackageFlags (pkg, false, RootContext.ToplevelTypes.Compiler.Report);
1017                         if (pkgout == null)
1018                                 return;
1019
1020                         string [] xargs = pkgout.Trim (new Char [] {' ', '\n', '\r', '\t'}).
1021                                 Split (new Char [] { ' ', '\t'});
1022
1023                         foreach (string s in xargs){
1024                                 if (s.StartsWith ("-r:") || s.StartsWith ("/r:") || s.StartsWith ("/reference:")){
1025                                         string lib = s.Substring (s.IndexOf (':')+1);
1026
1027                                         Evaluator.LoadAssembly (lib);
1028                                         continue;
1029                                 }
1030                         }
1031                 }
1032 #endif
1033
1034                 /// <summary>
1035                 ///   Loads the assembly
1036                 /// </summary>
1037                 /// <remarks>
1038                 ///   Loads the specified assembly and makes its types
1039                 ///   available to the evaluator.  This is equivalent
1040                 ///   to passing the -pkg: command line flag to the C#
1041                 ///   compiler on the command line.
1042                 /// </remarks>
1043                 static public void LoadAssembly (string assembly)
1044                 {
1045                         Evaluator.LoadAssembly (assembly);
1046                 }
1047
1048                 /// <summary>
1049                 ///   Returns a list of available static methods.
1050                 /// </summary>
1051                 static public string help {
1052                         get {
1053                                 return "Static methods:\n" +
1054                                         "  Describe (object)       - Describes the object's type\n" +
1055                                         "  LoadPackage (package);  - Loads the given Package (like -pkg:FILE)\n" +
1056                                         "  LoadAssembly (assembly) - Loads the given assembly (like -r:ASSEMBLY)\n" +
1057                                         "  ShowVars ();            - Shows defined local variables.\n" +
1058                                         "  ShowUsing ();           - Show active using declarations.\n" +
1059                                         "  Prompt                  - The prompt used by the C# shell\n" +
1060                                         "  ContinuationPrompt      - The prompt for partial input\n" +
1061                                         "  Time(() -> { })         - Times the specified code\n" +
1062                                         "  quit;                   - You'll never believe it - this quits the repl!\n" +
1063                                         "  help;                   - This help text\n";
1064                         }
1065                 }
1066
1067                 /// <summary>
1068                 ///   Indicates to the read-eval-print-loop that the interaction should be finished.
1069                 /// </summary>
1070                 static public object quit {
1071                         get {
1072                                 QuitRequested = true;
1073
1074                                 // To avoid print null at the exit
1075                                 return typeof (Evaluator.NoValueSet);
1076                         }
1077                 }
1078
1079 #if !NET_2_1
1080                 /// <summary>
1081                 ///   Describes an object or a type.
1082                 /// </summary>
1083                 /// <remarks>
1084                 ///   This method will show a textual representation
1085                 ///   of the object's type.  If the object is a
1086                 ///   System.Type it renders the type directly,
1087                 ///   otherwise it renders the type returned by
1088                 ///   invoking GetType on the object.
1089                 /// </remarks>
1090                 static public string Describe (object x)
1091                 {
1092                         if (x == null)
1093                                 return "<null>";
1094
1095                         var type = x as Type ?? x.GetType ();
1096
1097                         StringWriter sw = new StringWriter ();
1098                         new Outline (type, sw, true, false, false).OutlineType ();
1099                         return sw.ToString ();
1100                 }
1101 #endif
1102         }
1103
1104         //
1105         // A local variable reference that will create a Field in a
1106         // Class with the resolved type.  This is necessary so we can
1107         // support "var" as a field type in a class declaration.
1108         //
1109         // We allow LocalVariableReferece to do the heavy lifting, and
1110         // then we insert the field with the resolved type
1111         //
1112         public class LocalVariableReferenceWithClassSideEffect : LocalVariableReference {
1113                 TypeContainer container;
1114                 string name;
1115
1116                 public LocalVariableReferenceWithClassSideEffect (TypeContainer container, string name, Block current_block, string local_variable_id, LocalInfo li, Location loc)
1117                         : base (current_block, local_variable_id, loc, li, false)
1118                 {
1119                         this.container = container;
1120                         this.name = name;
1121                 }
1122
1123                 public override bool Equals (object obj)
1124                 {
1125                         LocalVariableReferenceWithClassSideEffect lvr = obj as LocalVariableReferenceWithClassSideEffect;
1126                         if (lvr == null)
1127                                 return false;
1128
1129                         if (lvr.name != name || lvr.container != container)
1130                                 return false;
1131
1132                         return base.Equals (obj);
1133                 }
1134
1135                 public override int GetHashCode ()
1136                 {
1137                         return name.GetHashCode ();
1138                 }
1139
1140                 override public Expression DoResolveLValue (ResolveContext ec, Expression right_side)
1141                 {
1142                         Expression ret = base.DoResolveLValue (ec, right_side);
1143                         if (ret == null)
1144                                 return null;
1145
1146                         Field f = new Field (container, new TypeExpression (ret.Type, Location),
1147                                              Modifiers.PUBLIC | Modifiers.STATIC,
1148                                              new MemberName (name, Location), null);
1149                         container.AddField (f);
1150                         if (f.Define ())
1151                                 Evaluator.QueueField (f);
1152
1153                         return ret;
1154                 }
1155         }
1156
1157         /// <summary>
1158         ///    A class used to assign values if the source expression is not void
1159         ///
1160         ///    Used by the interactive shell to allow it to call this code to set
1161         ///    the return value for an invocation.
1162         /// </summary>
1163         class OptionalAssign : SimpleAssign {
1164                 public OptionalAssign (Expression t, Expression s, Location loc)
1165                         : base (t, s, loc)
1166                 {
1167                 }
1168
1169                 protected override Expression DoResolve (ResolveContext ec)
1170                 {
1171                         CloneContext cc = new CloneContext ();
1172                         Expression clone = source.Clone (cc);
1173
1174                         //
1175                         // A useful feature for the REPL: if we can resolve the expression
1176                         // as a type, Describe the type;
1177                         //
1178                         if (Evaluator.DescribeTypeExpressions){
1179                                 var old_printer = Evaluator.SetPrinter (new StreamReportPrinter (TextWriter.Null));
1180                                 clone = clone.Resolve (ec);
1181                                 if (clone == null){
1182                                         clone = source.Clone (cc);
1183                                         clone = clone.Resolve (ec, ResolveFlags.Type);
1184                                         if (clone == null){
1185                                                 Evaluator.SetPrinter (old_printer);
1186                                                 clone = source.Clone (cc);
1187                                                 clone = clone.Resolve (ec);
1188                                                 return null;
1189                                         }
1190
1191                                         Arguments args = new Arguments (1);
1192                                         args.Add (new Argument (new TypeOf ((TypeExpr) clone, Location)));
1193                                         source = new Invocation (new SimpleName ("Describe", Location), args).Resolve (ec);
1194                                 }
1195                                 Evaluator.SetPrinter (old_printer);
1196                         } else {
1197                                 clone = clone.Resolve (ec);
1198                                 if (clone == null)
1199                                         return null;
1200                         }
1201
1202                         // This means its really a statement.
1203                         if (clone.Type == TypeManager.void_type){
1204                                 source = source.Resolve (ec);
1205                                 target = null;
1206                                 type = TypeManager.void_type;
1207                                 eclass = ExprClass.Value;
1208                                 return this;
1209                         }
1210
1211                         return base.DoResolve (ec);
1212                 }
1213
1214                 public override void Emit (EmitContext ec)
1215                 {
1216                         if (target == null)
1217                                 source.Emit (ec);
1218                         else
1219                                 base.Emit (ec);
1220                 }
1221
1222                 public override void EmitStatement (EmitContext ec)
1223                 {
1224                         if (target == null)
1225                                 source.Emit (ec);
1226                         else
1227                                 base.EmitStatement (ec);
1228                 }
1229         }
1230
1231         public class Undo {
1232                 List<KeyValuePair<TypeContainer, TypeContainer>> undo_types;
1233
1234                 public Undo ()
1235                 {
1236                         undo_types = new List<KeyValuePair<TypeContainer, TypeContainer>> ();
1237                 }
1238
1239                 public void AddTypeContainer (TypeContainer current_container, TypeContainer tc)
1240                 {
1241                         if (current_container == tc){
1242                                 Console.Error.WriteLine ("Internal error: inserting container into itself");
1243                                 return;
1244                         }
1245
1246                         if (undo_types == null)
1247                                 undo_types = new List<KeyValuePair<TypeContainer, TypeContainer>> ();
1248
1249                         undo_types.Add (new KeyValuePair<TypeContainer, TypeContainer> (current_container, tc));
1250                 }
1251
1252                 public void ExecuteUndo ()
1253                 {
1254                         if (undo_types == null)
1255                                 return;
1256
1257                         foreach (var p in undo_types){
1258                                 TypeContainer current_container = p.Key;
1259
1260                                 current_container.RemoveTypeContainer (p.Value);
1261                         }
1262                         undo_types = null;
1263                 }
1264         }
1265
1266 }
1267