shared source/sscli20/jscript/engine/typeof.cs

   1 // ==++==
   2 //
   3 //
   4 //    Copyright (c) 2006 Microsoft Corporation.  All rights reserved.
   5 //
   6 //    The use and distribution terms for this software are contained in the file
   7 //    named license.txt, which can be found in the root of this distribution.
   8 //    By using this software in any fashion, you are agreeing to be bound by the
   9 //    terms of this license.
  10 //
  11 //    You must not remove this notice, or any other, from this software.
  12 //
  13 //
  14 // ==--==
  15
  16 namespace Microsoft.JScript {
  17
  18     using Microsoft.JScript.Vsa;
  19     using System;
  20     using System.Reflection;
  21     using System.Reflection.Emit;
  22
  23     public sealed class Typeof : UnaryOp{
  24       internal Typeof(Context context, AST operand)
  25         : base(context, operand) {
  26       }
  27
  28       internal override Object Evaluate(){
  29         try{
  30           return JScriptTypeof(this.operand.Evaluate(), VsaEngine.executeForJSEE);
  31         }catch(JScriptException e){
  32           if ((e.Number & 0xFFFF) == (int)JSError.UndefinedIdentifier)
  33             return "undefined";
  34           throw e;
  35         }
  36       }
  37
  38       internal override IReflect InferType(JSField inference_target){
  39         return Typeob.String;
  40       }
  41
  42       public static String JScriptTypeof(Object value){
  43         return JScriptTypeof(value, false);
  44       }
  45
  46       internal static String JScriptTypeof(Object value, bool checkForDebuggerObject){
  47         switch (Convert.GetTypeCode(value)){
  48           case TypeCode.Empty:
  49             return "undefined";
  50           case TypeCode.DBNull:
  51             return "object";
  52           case TypeCode.Object:
  53             if (value is Missing || value is System.Reflection.Missing) return "undefined";
  54             return value is ScriptFunction ? "function" : "object";
  55           case TypeCode.Boolean:
  56             return "boolean";
  57           case TypeCode.Char:
  58           case TypeCode.String:
  59             return "string";
  60           case TypeCode.SByte:
  61           case TypeCode.Byte:
  62           case TypeCode.Int16:
  63           case TypeCode.UInt16:
  64           case TypeCode.Int32:
  65           case TypeCode.UInt32:
  66           case TypeCode.Int64:
  67           case TypeCode.UInt64:
  68           case TypeCode.Single:
  69           case TypeCode.Double:
  70           case TypeCode.Decimal:
  71             return "number";
  72           case TypeCode.DateTime:
  73             return "date";
  74         }
  75         return "unknown";
  76       }
  77
  78       internal override void TranslateToIL(ILGenerator il, Type rtype){
  79         if (this.operand is Binding)
  80           //Make sure that no exception is thrown if the operand is an undefined identifier
  81           ((Binding)this.operand).TranslateToIL(il, Typeob.Object, true);
  82         else
  83           this.operand.TranslateToIL(il, Typeob.Object);
  84         il.Emit(OpCodes.Call, CompilerGlobals.jScriptTypeofMethod);
  85         Convert.Emit(this, il, Typeob.String, rtype);
  86       }
  87     }
  88 }