microsoft-visualbasic-runtime/Language/Value/Variant.vb

#Region "Microsoft.VisualBasic::2d29578eb084446232659083838a7492, Microsoft.VisualBasic.Core\Language\Value\Variant.vb"

' Author:
' 
'       asuka (amethyst.asuka@gcmodeller.org)
'       xie (genetics@smrucc.org)
'       xieguigang (xie.guigang@live.com)
' 
' Copyright (c) 2018 GPL3 Licensed
' 
' 
' GNU GENERAL PUBLIC LICENSE (GPL3)
' 
' 
' This program is free software: you can redistribute it and/or modify
' it under the terms of the GNU General Public License as published by
' the Free Software Foundation, either version 3 of the License, or
' (at your option) any later version.
' 
' This program is distributed in the hope that it will be useful,
' but WITHOUT ANY WARRANTY; without even the implied warranty of
' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
' GNU General Public License for more details.
' 
' You should have received a copy of the GNU General Public License
' along with this program. If not, see <http://www.gnu.org/licenses/>.



' /********************************************************************************/

' Summaries:

'     Class [Variant]
' 
'         Properties: VA, VB
' 
'         Function: GetUnderlyingType
'         Operators: (+2 Overloads) <>, (+2 Overloads) =
' 
'     Class [Variant]
' 
'         Properties: VC
' 
' 
' /********************************************************************************/

#End Region

Imports System.Runtime.CompilerServices

Namespace Language

    Public Class [Variant](Of A, B) : Inherits Value(Of Object)

        Public Overrides Function GetUnderlyingType() As Type
            If Value Is Nothing Then
                Return GetType(Void)
            Else
                Return Value.GetType
            End If
        End Function

        Public ReadOnly Property VA As A
            <MethodImpl(MethodImplOptions.AggressiveInlining)>
            Get
                Return Value
            End Get
        End Property

        Public ReadOnly Property VB As B
            <MethodImpl(MethodImplOptions.AggressiveInlining)>
            Get
                Return Value
            End Get
        End Property

        Sub New()
        End Sub

        Sub New(a As A)
            Value = a
        End Sub

        Sub New(b As B)
            Value = b
        End Sub

        Public Function [TryCast](Of T)() As T
            Return DirectCast(Value, T)
        End Function

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Widening Operator CType(obj As [Variant](Of A, B)) As Type
            Return obj.GetUnderlyingType
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Narrowing Operator CType(obj As [Variant](Of A, B)) As A
            Return obj.VA
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Narrowing Operator CType(obj As [Variant](Of A, B)) As B
            Return obj.VB
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Widening Operator CType(a As A) As [Variant](Of A, B)
            Return New [Variant](Of A, B) With {.Value = a}
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Widening Operator CType(b As B) As [Variant](Of A, B)
            Return New [Variant](Of A, B) With {.Value = b}
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Operator =(obj As [Variant](Of A, B), a As A) As Boolean
            Return obj.VA.Equals(a)
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Operator <>(obj As [Variant](Of A, B), a As A) As Boolean
            Return Not obj = a
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Operator =(obj As [Variant](Of A, B), b As B) As Boolean
            Return obj.VB.Equals(b)
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Operator <>(obj As [Variant](Of A, B), b As B) As Boolean
            Return Not obj = b
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Operator Like(var As [Variant](Of A, B), type As Type) As Boolean
            Return var.GetUnderlyingType Is type
        End Operator
    End Class

    Public Class [Variant](Of A, B, C) : Inherits [Variant](Of A, B)

        Public ReadOnly Property VC As C
            <MethodImpl(MethodImplOptions.AggressiveInlining)>
            Get
                Return Value
            End Get
        End Property

        Sub New()
        End Sub

        Sub New(a As A)
            Value = a
        End Sub

        Sub New(b As B)
            Value = b
        End Sub

        Sub New(c As C)
            Value = c
        End Sub

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Narrowing Operator CType(obj As [Variant](Of A, B, C)) As C
            Return obj.VC
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Narrowing Operator CType(obj As [Variant](Of A, B, C)) As A
            Return obj.VA
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Narrowing Operator CType(obj As [Variant](Of A, B, C)) As B
            Return obj.VB
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Widening Operator CType(c As C) As [Variant](Of A, B, C)
            Return New [Variant](Of A, B, C) With {.Value = c}
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Widening Operator CType(a As A) As [Variant](Of A, B, C)
            Return New [Variant](Of A, B, C) With {.Value = a}
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Widening Operator CType(b As B) As [Variant](Of A, B, C)
            Return New [Variant](Of A, B, C) With {.Value = b}
        End Operator

        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Overloads Shared Operator Like(var As [Variant](Of A, B, C), type As Type) As Boolean
            Return var.GetUnderlyingType Is type
        End Operator
    End Class
End Namespace