2 // eval.cs: Evaluation and Hosting API for the C# compiler
5 // Miguel de Icaza (miguel@gnome.org)
6 // Marek Safar (marek.safar@gmail.com)
8 // Dual licensed under the terms of the MIT X11 or GNU GPL
10 // Copyright 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
11 // Copyright 2004-2011 Novell, Inc
12 // Copyright 2011 Xamarin Inc
16 using System.Threading;
17 using System.Collections.Generic;
18 using System.Reflection;
19 using System.Reflection.Emit;
30 public delegate void ValueModificationHandler (string variableName, int row, int column, object value);
33 /// Evaluator: provides an API to evaluate C# statements and
34 /// expressions dynamically.
37 /// This class exposes static methods to evaluate expressions in the
40 /// To initialize the evaluator with a number of compiler
41 /// options call the Init(string[]args) method with a set of
42 /// command line options that the compiler recognizes.
44 /// To interrupt execution of a statement, you can invoke the
45 /// Evaluator.Interrupt method.
47 public class Evaluator {
50 // Parse silently, do not output any error messages
53 // Report errors during parse
56 // Auto-complete, means that the tokenizer will start producing
57 // GETCOMPLETIONS tokens when it reaches a certain point.
61 static object evaluator_lock = new object ();
62 static volatile bool invoking;
67 static Thread invoke_thread;
69 readonly Dictionary<string, Tuple<FieldSpec, FieldInfo>> fields;
75 readonly CompilerContext ctx;
76 readonly ModuleContainer module;
77 readonly ReflectionImporter importer;
78 readonly CompilationSourceFile source_file;
82 public Evaluator (CompilerContext ctx)
86 module = new ModuleContainer (ctx);
87 module.Evaluator = this;
89 source_file = new CompilationSourceFile (module, null);
90 module.AddTypeContainer (source_file);
92 startup_files = ctx.SourceFiles.Count;
94 // FIXME: Importer needs this assembly for internalsvisibleto
95 module.SetDeclaringAssembly (new AssemblyDefinitionDynamic (module, "evaluator"));
96 importer = new ReflectionImporter (module, ctx.BuiltinTypes);
98 InteractiveBaseClass = typeof (InteractiveBase);
99 fields = new Dictionary<string, Tuple<FieldSpec, FieldInfo>> ();
104 var loader = new DynamicLoader (importer, ctx);
106 CompilerCallableEntryPoint.Reset ();
107 RootContext.ToplevelTypes = module;
109 //var startup_files = new List<string> ();
110 //foreach (CompilationUnit file in Location.SourceFiles)
111 // startup_files.Add (file.Path);
113 loader.LoadReferences (module);
114 ctx.BuiltinTypes.CheckDefinitions (module);
115 module.InitializePredefinedTypes ();
120 void ParseStartupFiles ()
122 Driver d = new Driver (ctx);
124 Location.Initialize (ctx.SourceFiles);
126 var parser_session = new ParserSession ();
127 for (int i = 0; i < startup_files; ++i) {
128 var sf = ctx.SourceFiles [i];
129 d.Parse (sf, module, parser_session, ctx.Report);
135 CompilerCallableEntryPoint.PartialReset ();
138 Location.Initialize (ctx.SourceFiles);
142 /// When set evaluator will automatically wait on Task of async methods. When not
143 /// set it's called responsibility to handle Task execution
145 public bool WaitOnTask { get; set; }
148 /// If true, turns type expressions into valid expressions
149 /// and calls the describe method on it
151 public bool DescribeTypeExpressions;
154 /// Whether the evaluator will use terse syntax, and the semicolons at the end are optional
156 public bool Terse = true;
159 /// The base class for the classes that host the user generated code
163 /// This is the base class that will host the code
164 /// executed by the Evaluator. By default
165 /// this is the Mono.CSharp.InteractiveBase class
166 /// which is useful for interactive use.
168 /// By changing this property you can control the
169 /// base class and the static members that are
170 /// available to your evaluated code.
172 public Type InteractiveBaseClass {
179 if (value != null && typeof (InteractiveBase).IsAssignableFrom (value))
180 InteractiveBase.Evaluator = this;
185 /// Interrupts the evaluation of an expression executing in Evaluate.
188 /// Use this method to interrupt long-running invocations.
190 public void Interrupt ()
192 if (!inited || !invoking)
195 if (invoke_thread != null)
196 invoke_thread.Abort ();
200 /// Compiles the input string and returns a delegate that represents the compiled code.
204 /// Compiles the input string as a C# expression or
205 /// statement, unlike the Evaluate method, the
206 /// resulting delegate can be invoked multiple times
207 /// without incurring in the compilation overhead.
209 /// If the return value of this function is null,
210 /// this indicates that the parsing was complete.
211 /// If the return value is a string it indicates
212 /// that the input string was partial and that the
213 /// invoking code should provide more code before
214 /// the code can be successfully compiled.
216 /// If you know that you will always get full expressions or
217 /// statements and do not care about partial input, you can use
218 /// the other Compile overload.
220 /// On success, in addition to returning null, the
221 /// compiled parameter will be set to the delegate
222 /// that can be invoked to execute the code.
225 public string Compile (string input, out CompiledMethod compiled)
227 if (input == null || input.Length == 0){
232 lock (evaluator_lock){
235 ParseStartupFiles ();
237 ctx.Report.Printer.Reset ();
241 CSharpParser parser = ParseString (ParseMode.Silent, input, out partial_input);
243 // Terse mode, try to provide the trailing semicolon automatically.
244 if (parser == null && Terse && partial_input){
247 // check if the source would compile with a block, if so, we should not
248 // add the semicolon.
249 var needs_block = ParseString (ParseMode.Silent, input + "{}", out ignore) != null;
251 parser = ParseString (ParseMode.Silent, input + ";", out ignore);
258 ParseString (ParseMode.ReportErrors, input, out partial_input);
262 Class parser_result = parser.InteractiveResult;
263 compiled = CompileBlock (parser_result, parser.undo, ctx.Report);
269 /// Compiles the input string and returns a delegate that represents the compiled code.
273 /// Compiles the input string as a C# expression or
274 /// statement, unlike the Evaluate method, the
275 /// resulting delegate can be invoked multiple times
276 /// without incurring in the compilation overhead.
278 /// This method can only deal with fully formed input
279 /// strings and does not provide a completion mechanism.
280 /// If you must deal with partial input (for example for
281 /// interactive use) use the other overload.
283 /// On success, a delegate is returned that can be used
284 /// to invoke the method.
287 public CompiledMethod Compile (string input)
289 CompiledMethod compiled;
291 // Ignore partial inputs
292 if (Compile (input, out compiled) != null){
293 // Error, the input was partial.
297 // Either null (on error) or the compiled method.
301 static MethodInfo listener_proxy_value;
302 internal void EmitValueChangedCallback (EmitContext ec, string name, TypeSpec type, Location loc)
304 if (listener_id == null)
305 listener_id = ListenerProxy.Register (ModificationListener);
307 if (listener_proxy_value == null)
308 listener_proxy_value = typeof (ListenerProxy).GetMethod ("ValueChanged");
311 throw new NotSupportedException ();
313 // object value, int row, int col, string name, int listenerId
314 if (type.IsStructOrEnum)
315 ec.Emit (OpCodes.Box, type);
317 ec.EmitInt (loc.Row);
318 ec.EmitInt (loc.Column);
319 ec.Emit (OpCodes.Ldstr, name);
320 ec.EmitInt (listener_id.Value);
321 ec.Emit (OpCodes.Call, listener_proxy_value);
326 /// Evaluates and expression or statement and returns any result values.
329 /// Evaluates the input string as a C# expression or
330 /// statement. If the input string is an expression
331 /// the result will be stored in the result variable
332 /// and the result_set variable will be set to true.
334 /// It is necessary to use the result/result_set
335 /// pair to identify when a result was set (for
336 /// example, execution of user-provided input can be
337 /// an expression, a statement or others, and
338 /// result_set would only be set if the input was an
341 /// If the return value of this function is null,
342 /// this indicates that the parsing was complete.
343 /// If the return value is a string, it indicates
344 /// that the input is partial and that the user
345 /// should provide an updated string.
347 public string Evaluate (string input, out object result, out bool result_set)
349 CompiledMethod compiled;
354 input = Compile (input, out compiled);
358 if (compiled == null)
362 // The code execution does not need to keep the compiler lock
364 object retval = typeof (QuitValue);
367 invoke_thread = System.Threading.Thread.CurrentThread;
369 compiled (ref retval);
370 } catch (ThreadAbortException e){
371 Thread.ResetAbort ();
372 Console.WriteLine ("Interrupted!\n{0}", e);
376 if (listener_id != null) {
377 ListenerProxy.Unregister (listener_id.Value);
383 // We use a reference to a compiler type, in this case
384 // Driver as a flag to indicate that this was a statement
386 if (!ReferenceEquals (retval, typeof (QuitValue))) {
394 public string [] GetCompletions (string input, out string prefix)
397 if (input == null || input.Length == 0)
400 lock (evaluator_lock){
405 CSharpParser parser = ParseString (ParseMode.GetCompletions, input, out partial_input);
410 Class host = parser.InteractiveResult;
412 var base_class_imported = importer.ImportType (base_class);
413 var baseclass_list = new List<FullNamedExpression> (1) {
414 new TypeExpression (base_class_imported, host.Location)
416 host.SetBaseTypes (baseclass_list);
419 var access = AssemblyBuilderAccess.RunAndCollect;
421 var access = AssemblyBuilderAccess.Run;
423 var a = new AssemblyDefinitionDynamic (module, "completions");
424 a.Create (AppDomain.CurrentDomain, access);
425 module.SetDeclaringAssembly (a);
427 // Need to setup MemberCache
428 host.CreateContainer ();
429 // Need to setup base type
430 host.DefineContainer ();
432 var method = host.Members[0] as Method;
433 BlockContext bc = new BlockContext (method, method.Block, ctx.BuiltinTypes.Void);
436 method.Block.Resolve (bc, method);
437 } catch (CompletionResult cr) {
438 prefix = cr.BaseText;
446 /// Executes the given expression or statement.
449 /// Executes the provided statement, returns true
450 /// on success, false on parsing errors. Exceptions
451 /// might be thrown by the called code.
453 public bool Run (string statement)
458 return Evaluate (statement, out result, out result_set) == null;
462 /// Evaluates and expression or statement and returns the result.
465 /// Evaluates the input string as a C# expression or
466 /// statement and returns the value.
468 /// This method will throw an exception if there is a syntax error,
469 /// of if the provided input is not an expression but a statement.
471 public object Evaluate (string input)
476 string r = Evaluate (input, out result, out result_set);
479 throw new ArgumentException ("Syntax error on input: partial input");
481 if (result_set == false)
482 throw new ArgumentException ("The expression failed to resolve");
490 public ValueModificationHandler ModificationListener { get; set; }
494 StatementOrExpression,
500 // Deambiguates the input string to determine if we
501 // want to process a statement or if we want to
502 // process a compilation unit.
504 // This is done using a top-down predictive parser,
505 // since the yacc/jay parser can not deambiguage this
506 // without more than one lookahead token. There are very
509 InputKind ToplevelOrStatement (SeekableStreamReader seekable)
511 Tokenizer tokenizer = new Tokenizer (seekable, source_file, new ParserSession (), ctx.Report);
513 // Prefer contextual block keywords over identifiers
514 tokenizer.parsing_block++;
516 int t = tokenizer.token ();
519 return InputKind.EOF;
521 // These are toplevels
523 case Token.OPEN_BRACKET:
527 case Token.INTERFACE:
529 case Token.NAMESPACE:
531 case Token.PROTECTED:
536 return InputKind.CompilationUnit;
538 // Definitely expression
555 return InputKind.StatementOrExpression;
557 // These need deambiguation help
559 t = tokenizer.token ();
561 return InputKind.EOF;
563 if (t == Token.IDENTIFIER || t == Token.STATIC)
564 return InputKind.CompilationUnit;
565 return InputKind.StatementOrExpression;
568 // Distinguish between:
569 // delegate opt_anonymous_method_signature block
572 t = tokenizer.token ();
574 return InputKind.EOF;
575 if (t == Token.OPEN_PARENS || t == Token.OPEN_BRACE)
576 return InputKind.StatementOrExpression;
577 return InputKind.CompilationUnit;
579 // Distinguih between:
581 // unsafe as modifier of a type declaration
583 t = tokenizer.token ();
585 return InputKind.EOF;
586 if (t == Token.OPEN_PARENS)
587 return InputKind.StatementOrExpression;
588 return InputKind.CompilationUnit;
590 // These are errors: we list explicitly what we had
591 // from the grammar, ERROR and then everything else
596 return InputKind.Error;
598 // This catches everything else allowed by
599 // expressions. We could add one-by-one use cases
602 return InputKind.StatementOrExpression;
607 // Parses the string @input and returns a CSharpParser if succeeful.
609 // if @silent is set to true then no errors are
610 // reported to the user. This is used to do various calls to the
611 // parser and check if the expression is parsable.
613 // @partial_input: if @silent is true, then it returns whether the
614 // parsed expression was partial, and more data is needed
616 CSharpParser ParseString (ParseMode mode, string input, out bool partial_input)
618 partial_input = false;
621 var enc = ctx.Settings.Encoding;
622 var s = new MemoryStream (enc.GetBytes (input));
623 SeekableStreamReader seekable = new SeekableStreamReader (s, enc);
625 InputKind kind = ToplevelOrStatement (seekable);
626 if (kind == InputKind.Error){
627 if (mode == ParseMode.ReportErrors)
628 ctx.Report.Error (-25, "Detection Parsing Error");
629 partial_input = false;
633 if (kind == InputKind.EOF){
634 if (mode == ParseMode.ReportErrors)
635 Console.Error.WriteLine ("Internal error: EOF condition should have been detected in a previous call with silent=true");
636 partial_input = true;
640 seekable.Position = 0;
642 source_file.DeclarationFound = false;
643 CSharpParser parser = new CSharpParser (seekable, source_file, new ParserSession ());
645 if (kind == InputKind.StatementOrExpression){
646 parser.Lexer.putback_char = Tokenizer.EvalStatementParserCharacter;
647 parser.Lexer.parsing_block++;
648 ctx.Settings.StatementMode = true;
650 parser.Lexer.putback_char = Tokenizer.EvalCompilationUnitParserCharacter;
651 ctx.Settings.StatementMode = false;
654 if (mode == ParseMode.GetCompletions)
655 parser.Lexer.CompleteOnEOF = true;
657 ReportPrinter old_printer = null;
658 if ((mode == ParseMode.Silent || mode == ParseMode.GetCompletions))
659 old_printer = ctx.Report.SetPrinter (new StreamReportPrinter (TextWriter.Null));
664 if (ctx.Report.Errors != 0){
665 if (mode != ParseMode.ReportErrors && parser.UnexpectedEOF)
666 partial_input = true;
668 if (parser.undo != null)
669 parser.undo.ExecuteUndo ();
674 if (old_printer != null)
675 ctx.Report.SetPrinter (old_printer);
680 CompiledMethod CompileBlock (Class host, Undo undo, Report Report)
683 throw new NotSupportedException ();
685 string current_debug_name = "eval-" + count + ".dll";
688 AssemblyDefinitionDynamic assembly;
689 AssemblyBuilderAccess access;
691 if (Environment.GetEnvironmentVariable ("SAVE") != null) {
692 access = AssemblyBuilderAccess.RunAndSave;
693 assembly = new AssemblyDefinitionDynamic (module, current_debug_name, current_debug_name);
694 assembly.Importer = importer;
697 access = AssemblyBuilderAccess.RunAndCollect;
699 access = AssemblyBuilderAccess.Run;
701 assembly = new AssemblyDefinitionDynamic (module, current_debug_name);
704 assembly.Create (AppDomain.CurrentDomain, access);
706 Method expression_method;
708 var base_class_imported = importer.ImportType (base_class);
709 var baseclass_list = new List<FullNamedExpression> (1) {
710 new TypeExpression (base_class_imported, host.Location)
713 host.SetBaseTypes (baseclass_list);
715 expression_method = (Method) host.Members[0];
717 if ((expression_method.ModFlags & Modifiers.ASYNC) != 0) {
719 // Host method is async. When WaitOnTask is set we wrap it with wait
721 // void AsyncWait (ref object $retval) {
723 // ((Task)$retval).Wait(); // When WaitOnTask is set
726 var p = new ParametersCompiled (
727 new Parameter (new TypeExpression (module.Compiler.BuiltinTypes.Object, Location.Null), "$retval", Parameter.Modifier.REF, null, Location.Null)
730 var method = new Method(host, new TypeExpression(module.Compiler.BuiltinTypes.Void, Location.Null),
731 Modifiers.PUBLIC | Modifiers.STATIC, new MemberName("AsyncWait"), p, null);
733 method.Block = new ToplevelBlock(method.Compiler, p, Location.Null);
734 method.Block.AddStatement(new StatementExpression (new SimpleAssign(
735 new SimpleName(p [0].Name, Location.Null),
736 new Invocation(new SimpleName(expression_method.MemberName.Name, Location.Null), new Arguments(0)),
737 Location.Null), Location.Null));
740 var task = new Cast (expression_method.TypeExpression, new SimpleName (p [0].Name, Location.Null), Location.Null);
742 method.Block.AddStatement (new StatementExpression (new Invocation (
743 new MemberAccess (task, "Wait", Location.Null),
744 new Arguments (0)), Location.Null));
747 host.AddMember(method);
749 expression_method = method;
752 host.CreateContainer();
753 host.DefineContainer();
757 expression_method = null;
760 module.CreateContainer ();
762 // Disable module and source file re-definition checks
763 module.EnableRedefinition ();
764 source_file.EnableRedefinition ();
768 if (Report.Errors != 0){
777 host.EmitContainer ();
780 module.EmitContainer ();
782 if (Report.Errors != 0){
788 module.CloseContainer ();
790 host.CloseContainer ();
792 if (access == AssemblyBuilderAccess.RunAndSave)
799 // Unlike Mono, .NET requires that the MethodInfo is fetched, it cant
800 // work from MethodBuilders. Retarded, I know.
802 var tt = assembly.Builder.GetType (host.TypeBuilder.Name);
803 var mi = tt.GetMethod (expression_method.MemberName.Name);
806 // We need to then go from FieldBuilder to FieldInfo
807 // or reflection gets confused (it basically gets confused, and variables override each
810 foreach (var member in host.Members) {
811 var field = member as Field;
815 var fi = tt.GetField (field.Name);
817 Tuple<FieldSpec, FieldInfo> old;
819 // If a previous value was set, nullify it, so that we do
821 if (fields.TryGetValue (field.Name, out old)) {
822 if (old.Item1.MemberType.IsStruct) {
824 // TODO: Clear fields for structs
828 old.Item2.SetValue (null, null);
834 fields[field.Name] = Tuple.Create (field.Spec, fi);
837 return (CompiledMethod) System.Delegate.CreateDelegate (typeof (CompiledMethod), mi);
842 /// A sentinel value used to indicate that no value was
843 /// was set by the compiled function. This is used to
844 /// differentiate between a function not returning a
847 internal static class QuitValue { }
849 internal Tuple<FieldSpec, FieldInfo> LookupField (string name)
851 Tuple<FieldSpec, FieldInfo> fi;
852 fields.TryGetValue (name, out fi);
856 static string Quote (string s)
858 if (s.IndexOf ('"') != -1)
859 s = s.Replace ("\"", "\\\"");
861 return "\"" + s + "\"";
864 public string GetUsing ()
866 if (source_file == null || source_file.Usings == null)
869 StringBuilder sb = new StringBuilder ();
871 //foreach (object x in ns.using_alias_list)
872 // sb.AppendFormat ("using {0};\n", x);
874 foreach (var ue in source_file.Usings) {
875 if (ue.Alias != null || ue.ResolvedExpression == null)
878 sb.AppendFormat("using {0};", ue.ToString ());
879 sb.Append (Environment.NewLine);
882 return sb.ToString ();
885 internal List<string> GetUsingList ()
887 var res = new List<string> ();
889 if (source_file == null || source_file.Usings == null)
892 foreach (var ue in source_file.Usings)
894 if (ue.Alias != null || ue.ResolvedExpression == null)
897 res.Add (ue.NamespaceExpression.Name);
903 internal string [] GetVarNames ()
905 lock (evaluator_lock){
906 return new List<string> (fields.Keys).ToArray ();
910 public string GetVars ()
912 lock (evaluator_lock){
913 StringBuilder sb = new StringBuilder ();
915 foreach (var de in fields){
916 var fi = LookupField (de.Key);
919 value = fi.Item2.GetValue (null);
921 value = Quote ((string)value);
923 value = "<error reading value>";
926 sb.AppendFormat ("{0} {1} = {2}", fi.Item1.MemberType.GetSignatureForError (), de.Key, value);
930 return sb.ToString ();
935 /// Loads the given assembly and exposes the API to the user.
937 public void LoadAssembly (string file)
939 var loader = new DynamicLoader (importer, ctx);
940 var assembly = loader.LoadAssemblyFile (file, false);
941 if (assembly == null)
944 lock (evaluator_lock){
945 importer.ImportAssembly (assembly, module.GlobalRootNamespace);
950 /// Exposes the API of the given assembly to the Evaluator
952 public void ReferenceAssembly (Assembly a)
954 lock (evaluator_lock){
955 importer.ImportAssembly (a, module.GlobalRootNamespace);
962 /// A delegate that can be used to invoke the
963 /// compiled expression or statement.
966 /// Since the Compile methods will compile
967 /// statements and expressions into the same
968 /// delegate, you can tell if a value was returned
969 /// by checking whether the returned value is of type
973 public delegate void CompiledMethod (ref object retvalue);
976 /// The default base class for every interaction line
979 /// The expressions and statements behave as if they were
980 /// a static method of this class. The InteractiveBase class
981 /// contains a number of useful methods, but can be overwritten
982 /// by setting the InteractiveBaseType property in the Evaluator
984 public class InteractiveBase {
986 /// Determines where the standard output of methods in this class will go.
988 public static TextWriter Output = Console.Out;
991 /// Determines where the standard error of methods in this class will go.
993 public static TextWriter Error = Console.Error;
996 /// The primary prompt used for interactive use.
998 public static string Prompt = "csharp> ";
1001 /// The secondary prompt used for interactive use (used when
1002 /// an expression is incomplete).
1004 public static string ContinuationPrompt = " > ";
1007 /// Used to signal that the user has invoked the `quit' statement.
1009 public static bool QuitRequested;
1011 public static Evaluator Evaluator;
1014 /// Shows all the variables defined so far.
1016 static public void ShowVars ()
1018 Output.Write (Evaluator.GetVars ());
1023 /// Displays the using statements in effect at this point.
1025 static public void ShowUsing ()
1027 Output.Write (Evaluator.GetUsing ());
1032 /// Times the execution of the given delegate
1034 static public TimeSpan Time (Action a)
1036 DateTime start = DateTime.Now;
1038 return DateTime.Now - start;
1042 /// Loads the assemblies from a package
1045 /// Loads the assemblies from a package. This is equivalent
1046 /// to passing the -pkg: command line flag to the C# compiler
1047 /// on the command line.
1049 static public void LoadPackage (string pkg)
1052 Error.WriteLine ("Invalid package specified");
1056 string pkgout = Driver.GetPackageFlags (pkg, null);
1058 string [] xargs = pkgout.Trim (new Char [] {' ', '\n', '\r', '\t'}).
1059 Split (new Char [] { ' ', '\t'});
1061 foreach (string s in xargs){
1062 if (s.StartsWith ("-r:") || s.StartsWith ("/r:") || s.StartsWith ("/reference:")){
1063 string lib = s.Substring (s.IndexOf (':')+1);
1065 Evaluator.LoadAssembly (lib);
1072 /// Loads the assembly
1075 /// Loads the specified assembly and makes its types
1076 /// available to the evaluator. This is equivalent
1077 /// to passing the -pkg: command line flag to the C#
1078 /// compiler on the command line.
1080 static public void LoadAssembly (string assembly)
1082 Evaluator.LoadAssembly (assembly);
1085 static public void print (object obj)
1087 Output.WriteLine (obj);
1090 static public void print (string fmt, params object [] args)
1092 Output.WriteLine (fmt, args);
1096 /// Returns a list of available static methods.
1098 static public string help {
1100 return "Static methods:\n" +
1101 " Describe (object); - Describes the object's type\n" +
1102 " LoadPackage (package); - Loads the given Package (like -pkg:FILE)\n" +
1103 " LoadAssembly (assembly); - Loads the given assembly (like -r:ASSEMBLY)\n" +
1104 " ShowVars (); - Shows defined local variables.\n" +
1105 " ShowUsing (); - Show active using declarations.\n" +
1106 " Prompt - The prompt used by the C# shell\n" +
1107 " ContinuationPrompt - The prompt for partial input\n" +
1108 " Time (() => { }); - Times the specified code\n" +
1109 " print (obj); - Shorthand for Console.WriteLine\n" +
1110 " quit; - You'll never believe it - this quits the repl!\n" +
1111 " help; - This help text\n";
1116 /// Indicates to the read-eval-print-loop that the interaction should be finished.
1118 static public object quit {
1120 QuitRequested = true;
1122 // To avoid print null at the exit
1123 return typeof (Evaluator.QuitValue);
1128 /// Same as quit - useful in script scenerios
1130 static public void Quit () {
1131 QuitRequested = true;
1136 /// Describes an object or a type.
1139 /// This method will show a textual representation
1140 /// of the object's type. If the object is a
1141 /// System.Type it renders the type directly,
1142 /// otherwise it renders the type returned by
1143 /// invoking GetType on the object.
1145 static public string Describe (object x)
1150 var type = x as Type ?? x.GetType ();
1152 StringWriter sw = new StringWriter ();
1153 new Outline (type, sw, true, false, false).OutlineType ();
1154 return sw.ToString ();
1159 class InteractiveMethod : Method
1161 public InteractiveMethod(TypeDefinition parent, FullNamedExpression returnType, Modifiers mod, ParametersCompiled parameters)
1162 : base(parent, returnType, mod, new MemberName("Host"), parameters, null)
1166 public void ChangeToAsync ()
1168 ModFlags |= Modifiers.ASYNC;
1169 ModFlags &= ~Modifiers.UNSAFE;
1170 type_expr = new TypeExpression(Module.PredefinedTypes.Task.TypeSpec, Location);
1171 parameters = ParametersCompiled.EmptyReadOnlyParameters;
1174 public override string GetSignatureForError()
1176 return "InteractiveHost";
1180 class HoistedEvaluatorVariable : HoistedVariable
1182 public HoistedEvaluatorVariable (Field field)
1183 : base (null, field)
1187 protected override FieldExpr GetFieldExpression (EmitContext ec)
1189 return new FieldExpr (field, field.Location);
1194 /// A class used to assign values if the source expression is not void
1196 /// Used by the interactive shell to allow it to call this code to set
1197 /// the return value for an invocation.
1199 class OptionalAssign : SimpleAssign {
1200 public OptionalAssign (Expression s, Location loc)
1201 : base (null, s, loc)
1205 public override Location StartLocation {
1207 return Location.Null;
1211 protected override Expression DoResolve (ResolveContext ec)
1213 Expression clone = source.Clone (new CloneContext ());
1215 clone = clone.Resolve (ec);
1220 // A useful feature for the REPL: if we can resolve the expression
1221 // as a type, Describe the type;
1223 if (ec.Module.Evaluator.DescribeTypeExpressions && !(ec.CurrentAnonymousMethod is AsyncInitializer)) {
1224 var old_printer = ec.Report.SetPrinter (new SessionReportPrinter ());
1227 // Note: clone context cannot be shared otherwise block mapping would leak
1228 tclone = source.Clone (new CloneContext ());
1229 tclone = tclone.Resolve (ec, ResolveFlags.Type);
1230 if (ec.Report.Errors > 0)
1233 ec.Report.SetPrinter (old_printer);
1236 if (tclone is TypeExpr) {
1237 Arguments args = new Arguments (1);
1238 args.Add (new Argument (new TypeOf ((TypeExpr) clone, Location)));
1239 return new Invocation (new SimpleName ("Describe", Location), args).Resolve (ec);
1243 // This means its really a statement.
1244 if (clone.Type.Kind == MemberKind.Void || clone is DynamicInvocation || clone is Assign) {
1250 var host = (Method) ec.MemberContext.CurrentMemberDefinition;
1252 if (host.ParameterInfo.IsEmpty) {
1253 eclass = ExprClass.Value;
1254 type = InternalType.FakeInternalType;
1258 target = new SimpleName (host.ParameterInfo[0].Name, Location);
1260 return base.DoResolve (ec);
1263 public override void EmitStatement(EmitContext ec)
1265 if (target == null) {
1270 base.EmitStatement(ec);
1276 List<Action> undo_actions;
1278 public void AddTypeContainer (TypeContainer current_container, TypeDefinition tc)
1280 if (current_container == tc){
1281 Console.Error.WriteLine ("Internal error: inserting container into itself");
1285 if (undo_actions == null)
1286 undo_actions = new List<Action> ();
1288 if (current_container.Containers != null)
1290 var existing = current_container.Containers.FirstOrDefault (l => l.MemberName.Basename == tc.MemberName.Basename);
1291 if (existing != null) {
1292 current_container.RemoveContainer (existing);
1293 undo_actions.Add (() => current_container.AddTypeContainer (existing));
1297 undo_actions.Add (() => current_container.RemoveContainer (tc));
1300 public void ExecuteUndo ()
1302 if (undo_actions == null)
1305 foreach (var p in undo_actions){
1309 undo_actions = null;
1313 static class ListenerProxy
1315 static readonly Dictionary<int, ValueModificationHandler> listeners = new Dictionary<int, ValueModificationHandler> ();
1319 public static int Register (ValueModificationHandler listener)
1323 listeners.Add (id, listener);
1328 public static void Unregister (int listenerId)
1331 listeners.Remove (listenerId);
1335 public static void ValueChanged (object value, int row, int col, string name, int listenerId)
1337 ValueModificationHandler action;
1339 if (!listeners.TryGetValue (listenerId, out action))
1343 action (name, row, col, value);