mcs/class/Microsoft.JScript/Microsoft.JScript/Equality.cs

   1 //
   2 // Equality.cs:
   3 //
   4 // Author:
   5 //      Cesar Lopez Nataren (cesar@ciencias.unam.mx)
   6 //
   7 // (C) 2003, 2004 Cesar Lopez Nataren
   8 //
   9
  10 using System;
  11 using System.Text;
  12 using System.Reflection.Emit;
  13
  14 namespace Microsoft.JScript {
  15
  16         public class Equality : BinaryOp {
  17
  18                 internal Equality (AST parent, AST left, AST right, JSToken op)
  19                 {
  20                         this.left = left;
  21                         this.right = right;
  22                         this.current_op = op;
  23                 }
  24
  25                 public Equality (Context context, AST oper1, AST oper2, JSToken operatorTok)
  26                 {
  27                         throw new NotImplementedException ();
  28                 }
  29
  30                 public Equality (int i)
  31                 {
  32                         current_op = (JSToken) i;
  33                 }
  34
  35                 public bool EvaluateEquality (object v1, object v2)
  36                 {
  37                         return false;
  38                 }
  39
  40
  41                 public static bool JScriptEquals (object v1, object v2)
  42                 {
  43                         throw new NotImplementedException ();
  44                 }
  45
  46                 public override string ToString ()
  47                 {
  48                         StringBuilder sb = new StringBuilder ();
  49
  50                         sb.Append (left.ToString ());
  51
  52                         if (current_op != JSToken.None)
  53                                 sb.Append (current_op + " ");
  54
  55                         if (right != null)
  56                                 sb.Append (right.ToString ());
  57
  58                         return sb.ToString ();
  59                 }
  60
  61                 internal override bool Resolve (IdentificationTable context)
  62                 {
  63                         bool r = true;
  64                         if (left != null)
  65                                 r &= left.Resolve (context);
  66                         if (right != null)
  67                                 r &= right.Resolve (context);
  68                         return r;
  69                 }
  70
  71                 internal override bool Resolve (IdentificationTable context, bool no_effect)
  72                 {
  73                         this.no_effect = no_effect;
  74                         return  Resolve (context);
  75                 }
  76
  77                 internal override void Emit (EmitContext ec)
  78                 {
  79                         ILGenerator ig = ec.ig;
  80                         LocalBuilder local_builder;
  81
  82                         if (current_op != JSToken.None) {
  83                                 Type t = typeof (Equality);
  84                                 local_builder = ig.DeclareLocal (t);
  85                                 if (current_op == JSToken.Equal)
  86                                         ig.Emit (OpCodes.Ldc_I4_S, (byte) 53);
  87                                 else if (current_op == JSToken.NotEqual)
  88                                         ig.Emit (OpCodes.Ldc_I4_S, (byte) 54);
  89                                 ig.Emit (OpCodes.Newobj, t.GetConstructor (new Type [] {typeof (int)}));
  90                                 ig.Emit (OpCodes.Stloc, local_builder);
  91                                 ig.Emit (OpCodes.Ldloc, local_builder);
  92                         }
  93
  94                         if (left != null)
  95                                 left.Emit (ec);
  96                         if (right != null)
  97                                 right.Emit (ec);
  98
  99                         if (current_op == JSToken.Equal || current_op == JSToken.NotEqual) {
 100                                 ig.Emit (OpCodes.Call, typeof (Equality).GetMethod ("EvaluateEquality"));
 101
 102                                 if (no_effect) {
 103                                         Label t_lbl = ig.DefineLabel ();
 104                                         Label f_lbl = ig.DefineLabel ();
 105
 106                                         if (current_op == JSToken.Equal)
 107                                                 ig.Emit (OpCodes.Brtrue_S, t_lbl);
 108                                         else if (current_op == JSToken.NotEqual)
 109                                                 ig.Emit (OpCodes.Brfalse_S, t_lbl);
 110
 111                                         ig.Emit (OpCodes.Ldc_I4_0);
 112                                         ig.Emit (OpCodes.Br_S, f_lbl);
 113                                         ig.MarkLabel (t_lbl);
 114                                         ig.Emit (OpCodes.Ldc_I4_1);
 115                                         ig.MarkLabel (f_lbl);
 116                                         ig.Emit (OpCodes.Pop);
 117                                 }
 118                         }
 119                 }
 120         }
 121 }