* Version.cs (CompareTo, Equals): Make sure the versions for

[mono-project.git] / mcs / gmcs / literal.cs

//
// literal.cs: Literal representation for the IL tree.
//
// Author:
//   Miguel de Icaza (miguel@ximian.com)
//
// (C) 2001 Ximian, Inc.
//
//
// Notice that during parsing we create objects of type Literal, but the
// types are not loaded (thats why the Resolve method has to assign the
// type at that point).
//
// Literals differ from the constants in that we know we encountered them
// as a literal in the source code (and some extra rules apply there) and
// they have to be resolved (since during parsing we have not loaded the
// types yet) while constants are created only after types have been loaded
// and are fully resolved when born.
//

using System;
using System.Reflection;
using System.Reflection.Emit;

//
// I put System.Null just so we do not have to special case it on 
// TypeManager.CSharpName
//
namespace System {
        //
        // Represents the Null Type, just used as a placeholder for the type in NullLiteral
        //
        public class Null {
        }
}
        
namespace Mono.CSharp {

        //
        // The NullType just exists to compare type equality, and for
        // expressions that might have the `null type'
        //
        public class NullType {
        }

        //
        // The null Literal constant
        //
        public class NullLiteral : Constant {
                public static readonly NullLiteral Null;

                static NullLiteral ()
                {
                        Null = new NullLiteral ();
                }
                        
                public NullLiteral ()
                {
                        eclass = ExprClass.Value;
                }
                
                override public string AsString ()
                {
                        return "null";
                }

                public override object GetValue ()
                {
                        return null;
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.null_type;
                        return this;
                }

                public override void Emit (EmitContext ec)
                {
                        ec.ig.Emit (OpCodes.Ldnull);
                }
                
                public override bool IsNegative {
                        get {
                                return false;
                        }
                }

                public override bool IsZeroInteger {
                        get { return true; }
                }
        }

        //
        // A null literal in a pointer context
        //
        public class NullPointer : NullLiteral {
                public new static readonly NullLiteral Null;

                static NullPointer ()
                {
                        Null = new NullPointer ();
                }
                
                private NullPointer ()
                {
                        type = TypeManager.object_type;
                }

                public override void Emit (EmitContext ec)
                {
                        ILGenerator ig = ec.ig;
                                
                        ig.Emit (OpCodes.Ldc_I4_0);
                        ig.Emit (OpCodes.Conv_U);
                }
        }

        public class BoolLiteral : BoolConstant {
                public BoolLiteral (bool val) : base (val)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.bool_type;
                        return this;
                }
        }

        public class CharLiteral : CharConstant {
                public CharLiteral (char c) : base (c)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.char_type;
                        return this;
                }
        }

        public class IntLiteral : IntConstant {
                public static IntLiteral One, Zero;
                
                static IntLiteral ()
                {
                        Zero = new IntLiteral (0);
                        One = new IntLiteral (1);
                }
                
                public IntLiteral (int l) : base (l)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.int32_type;
                        return this;
                }
        }

        public class UIntLiteral : UIntConstant {
                public UIntLiteral (uint l) : base (l)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.uint32_type;
                        return this;
                }
        }
        
        public class LongLiteral : LongConstant {
                public LongLiteral (long l) : base (l)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.int64_type;

                        return this;
                }
        }

        public class ULongLiteral : ULongConstant {
                public ULongLiteral (ulong l) : base (l)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.uint64_type;
                        return this;
                }
        }
        
        public class FloatLiteral : FloatConstant {
                
                public FloatLiteral (float f) : base (f)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.float_type;
                        return this;
                }
        }

        public class DoubleLiteral : DoubleConstant {
                public DoubleLiteral (double d) : base (d)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.double_type;

                        return this;
                }
        }

        public class DecimalLiteral : DecimalConstant {
                public DecimalLiteral (decimal d) : base (d)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.decimal_type;
                        return this;
                }
        }

        public class StringLiteral : StringConstant {
                public StringLiteral (string s) : base (s)
                {
                }

                public override Expression DoResolve (EmitContext ec)
                {
                        type = TypeManager.string_type;

                        return this;
                }
        }
}