2 // const.cs: Constant declarations.
5 // Miguel de Icaza (miguel@ximian.com)
7 // (C) 2001 Ximian, Inc.
12 // This is needed because the following situation arises:
14 // The FieldBuilder is declared with the real type for an enumeration
16 // When we attempt to set the value for the constant, the FieldBuilder.SetConstant
17 // function aborts because it requires its argument to be of the same type
20 namespace Mono.CSharp {
23 using System.Reflection;
24 using System.Reflection.Emit;
25 using System.Collections;
27 public class Const : MemberCore {
28 public Expression ConstantType;
29 public Expression Expr;
30 public Attributes OptAttributes;
31 public FieldBuilder FieldBuilder;
33 object ConstantValue = null;
36 public const int AllowedModifiers =
43 public Const (Expression constant_type, string name, Expression expr, int mod_flags,
44 Attributes attrs, Location loc)
47 ConstantType = constant_type;
50 ModFlags = Modifiers.Check (AllowedModifiers, mod_flags, Modifiers.PRIVATE, loc);
51 OptAttributes = attrs;
54 public FieldAttributes FieldAttr {
56 return FieldAttributes.Literal | FieldAttributes.Static |
57 Modifiers.FieldAttr (ModFlags) ;
62 void dump_tree (Type t)
64 Console.WriteLine ("Dumping hierarchy");
66 Console.WriteLine (" " + t.FullName + " " +
67 (t.GetType ().IsEnum ? "yes" : "no"));
74 /// Defines the constant in the @parent
76 public override bool Define (TypeContainer parent)
78 type = parent.ResolveType (ConstantType, false, Location);
83 if (!TypeManager.IsBuiltinType (type) &&
84 (!type.IsSubclassOf (TypeManager.enum_type))) {
87 "Constant type is not valid (only system types are allowed)");
91 Type ptype = parent.TypeBuilder.BaseType;
94 MemberInfo [] mi = TypeContainer.FindMembers (
95 ptype, MemberTypes.Field, BindingFlags.Public,
96 Type.FilterName, Name);
98 if (mi == null || mi.Length == 0)
99 if ((ModFlags & Modifiers.NEW) != 0)
100 WarningNotHiding (parent);
102 } else if ((ModFlags & Modifiers.NEW) != 0)
103 WarningNotHiding (parent);
105 FieldBuilder = parent.TypeBuilder.DefineField (Name, type, FieldAttr);
107 TypeManager.RegisterConstant (FieldBuilder, this);
113 /// Looks up the value of a constant field. Defines it if it hasn't
114 /// already been. Similar to LookupEnumValue in spirit.
116 public object LookupConstantValue (EmitContext ec)
118 if (ConstantValue != null)
119 return ConstantValue;
121 Expr = Expr.Resolve (ec);
124 Report.Error (150, Location, "A constant value is expected");
128 if (!(Expr is Constant)) {
129 UnCheckedExpr un_expr = Expr as UnCheckedExpr;
130 CheckedExpr ch_expr = Expr as CheckedExpr;
132 if ((un_expr != null) && (un_expr.Expr is Constant))
134 else if ((ch_expr != null) && (ch_expr.Expr is Constant))
137 Report.Error (150, Location, "A constant value is expected");
142 ConstantValue = ((Constant) Expr).GetValue ();
144 if (type != Expr.Type) {
146 ConstantValue = TypeManager.ChangeType (ConstantValue, type);
148 Expression.Error_CannotConvertImplicit (Location, Expr.Type, type);
152 if (type == TypeManager.int32_type)
153 Expr = new IntConstant ((int) ConstantValue);
154 else if (type == TypeManager.uint32_type)
155 Expr = new UIntConstant ((uint) ConstantValue);
156 else if (type == TypeManager.int64_type)
157 Expr = new LongConstant ((long) ConstantValue);
158 else if (type == TypeManager.uint64_type)
159 Expr = new ULongConstant ((ulong) ConstantValue);
160 else if (type == TypeManager.float_type)
161 Expr = new FloatConstant ((float) ConstantValue);
162 else if (type == TypeManager.double_type)
163 Expr = new DoubleConstant ((double) ConstantValue);
164 else if (type == TypeManager.string_type)
165 Expr = new StringConstant ((string) ConstantValue);
166 else if (type == TypeManager.short_type)
167 Expr = new ShortConstant ((short) ConstantValue);
168 else if (type == TypeManager.ushort_type)
169 Expr = new UShortConstant ((ushort) ConstantValue);
170 else if (type == TypeManager.sbyte_type)
171 Expr = new SByteConstant ((sbyte) ConstantValue);
172 else if (type == TypeManager.byte_type)
173 Expr = new ByteConstant ((byte) ConstantValue);
174 else if (type == TypeManager.char_type)
175 Expr = new CharConstant ((char) ConstantValue);
176 else if (type == TypeManager.bool_type)
177 Expr = new BoolConstant ((bool) ConstantValue);
182 // This sadly does not work for our user-defined enumerations types ;-(
185 ConstantValue = System.Enum.ToObject (
186 type, ConstantValue);
187 } catch (ArgumentException){
190 ".NET SDK 1.0 does not permit to create the constant "+
191 " field from a user-defined enumeration");
195 FieldBuilder.SetConstant (ConstantValue);
197 if (!TypeManager.RegisterFieldValue (FieldBuilder, ConstantValue))
200 return ConstantValue;
205 /// Emits the field value by evaluating the expression
207 public void EmitConstant (TypeContainer parent)
209 EmitContext ec = new EmitContext (parent, Location, null, type, ModFlags);
210 LookupConstantValue (ec);