tokenmanager.vb

大名鼎鼎的mono是.NET平台的跨平台（支持linux

    ''' <param name="GotoNewline"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function AcceptIfNotError(ByVal Special As KS, ByVal Message As Messages, Optional ByVal GotoNewline As Boolean = False) As Boolean
        If Accept(Special) Then
            Return True
        Else
            If GotoNewline Then Me.GotoNewline(True)
            Compiler.Report.ShowMessage(Message)
            Return False
        End If
    End Function

    ''' <summary>
    ''' If GotoNewline = true then calls GotoNewline(True) - next token is the first one after the newline.
    ''' </summary>
    ''' <param name="Special"></param>
    ''' <param name="Message"></param>
    ''' <param name="GotoNewline"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    <Diagnostics.DebuggerHidden()> Function AcceptIfNotError(ByVal Special As KS, ByVal Message As Messages, ByVal GotoNewline As Boolean, ByVal MessageParameters() As String) As Boolean
        If Accept(Special) Then
            Return True
        Else
            If GotoNewline Then Me.GotoNewline(True)
            Compiler.Report.ShowMessage(Message, MessageParameters)
            Return False
        End If
    End Function

    <Diagnostics.DebuggerHidden()> Function AcceptIfNotError(ByVal Special As KS, ByVal Message As Messages, ByVal GotoNewline As Boolean, ByVal MessageParameter As String) As Boolean
        If Accept(Special) Then
            Return True
        Else
            If GotoNewline Then Me.GotoNewline(True)
            Compiler.Report.ShowMessage(Message, MessageParameter)
            Return False
        End If
    End Function
    ''' <summary>
    ''' GotoNewline defaults to false for this overload.
    ''' </summary>
    ''' <param name="Special"></param>
    ''' <param name="Message"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function AcceptIfNotError(ByVal Special As KS, ByVal Message As Messages, ByVal ParamArray MessageParameters() As String) As Boolean
        Return AcceptIfNotError(Special, Message, False, MessageParameters)
    End Function

    ''' <summary>
    ''' If GotoNewline = true then calls GotoNewline(True) - next token is the first one after the newline.
    ''' Accepts only newline, not endofcode, nor endoffile. 
    ''' </summary>
    ''' <param name="GotoNewline"></param>
    ''' <param name="EOFIsError">Specifies whether to return false if the current token is EOF or not.</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function AcceptNewLine(Optional ByVal GotoNewline As Boolean = False, Optional ByVal EOFIsError As Boolean = True, Optional ByVal ReportError As Boolean = False) As Boolean
        If CurrentToken.IsEndOfLine Then
            If CurrentToken.IsEndOfLineOnly Then
                NextToken()
                Return True
            ElseIf EOFIsError = False Then
                Return True
            Else
                Return False
            End If
        Else
            If GotoNewline Then Me.GotoNewline(True, ReportError)
            Return False
        End If
    End Function

    ''' <summary>
    ''' Accepts Newline or : (not endoffile, nor endofcode)
    ''' If ReportError = True then:
    '''  - reports an error if currenttoken != ks.colon AND currenttoken != newline
    '''    doesn't matter if OnlyColon is true or not.
    ''' </summary>
    ''' <param name="OnlyColon">Set to true to only accept colon, not even NewLine</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function AcceptEndOfStatement(Optional ByVal OnlyColon As Boolean = False, Optional ByVal ReportError As Boolean = False) As Boolean
        Dim result As Boolean = True
        If OnlyColon Then
            result = Accept(KS.Colon)
            If ReportError AndAlso result = False AndAlso CurrentToken.IsEndOfLineOnly = False Then
#If DEBUG Then
                System.Console.WriteLine("Found: " & CurrentToken.ToString)
#End If
                Compiler.Report.ShowMessage(Messages.VBNC30205)
            End If
            Return result
        Else
            If CurrentToken.IsEndOfLineOnly OrElse CurrentToken() = KS.Colon Then
                Do
                    NextToken()
                Loop While CurrentToken.IsEndOfLineOnly OrElse CurrentToken.Equals(KS.Colon)
                Return True
            Else
                If ReportError Then
#If DEBUG Then
                    System.Console.WriteLine("Found: " & CurrentToken.ToString)
#End If
                    Compiler.Report.ShowMessage(Messages.VBNC30205)
                End If
                Return False
            End If
        End If
    End Function

    Function AcceptEndOfFile() As Boolean
        If CurrentToken.IsEndOfFile Then
            NextToken()
            Return True
        Else
            Return False
        End If
    End Function

    Function AcceptIdentifier(ByRef result As Token) As Boolean
        Dim tmp As Token = CurrentToken()
        If CurrentToken.IsIdentifier Then
            result = CurrentToken()
            If tmp.IsIdentifier = False Then Throw New InternalException("Not an identifier?????")
            If CurrentToken.IsIdentifier = False Then Throw New InternalException("Not an identifier???")
            If result.IsIdentifier = False Then Throw New InternalException("Not an identifier?")
            NextToken()
            Return True
        Else
            Return False
        End If
    End Function

    ''' <summary>
    ''' Returns true if the current token is an identifier
    ''' and advances to the next token.
    ''' If GotoNewline = true then calls GotoNewline(True) - next token is the first one after the newline.
    ''' </summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function AcceptIdentifier(Optional ByVal GotoNewline As Boolean = False) As Boolean
        If CurrentToken.IsIdentifier Then
            NextToken()
            Return True
        Else
            If GotoNewline Then Me.GotoNewline(True)
            Return False
        End If
    End Function

    Function AcceptStringLiteral(Optional ByVal GotoNewline As Boolean = False) As Boolean
        If CurrentToken.IsStringLiteral Then
            NextToken()
            Return True
        Else
            If GotoNewline Then Me.GotoNewline(True)
            Return False
        End If
    End Function

    Shared Function AcceptStringLiteral(ByVal Reader As ITokenReader, Optional ByVal GotoNewline As Boolean = False) As Boolean
        If Reader.Peek.IsStringLiteral Then
            Reader.Next()
            Return True
        Else
            If GotoNewline Then tm.GotoNewline(Reader, True)
            Return False
        End If
    End Function
    ''' <summary>
    ''' If GotoNewline = true then calls GotoNewline(True) - next token is the first one after the newline.
    ''' </summary>
    ''' <param name="GotoNewline"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function AcceptIntegerLiteral(Optional ByVal GotoNewline As Boolean = False) As Boolean
        If CurrentToken.IsIntegerLiteral Then
            NextToken()
            Return True
        Else
            If GotoNewline Then Me.GotoNewline(True)
            Return False
        End If
    End Function

    ''' <summary>
    ''' If GotoNewline = true then calls GotoNewline(True) - next token is the first one after the newline.
    ''' </summary>
    ''' <param name="GotoNewline"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Shared Function AcceptIntegerLiteral(ByVal Reader As ITokenReader, Optional ByVal GotoNewline As Boolean = False) As Boolean
        If Reader.Peek.IsIntegerLiteral Then
            Reader.Next()
            Return True
        Else
            If GotoNewline Then tm.GotoNewline(Reader, True)
            Return False
        End If
    End Function

    ''' <summary>
    ''' If GotoNewline = true then calls GotoNewline(True) - next token is the first one after the newline.
    ''' </summary>
    ''' <param name="Special"></param>
    ''' <param name="GotoNewline"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function Accept(ByVal Special As KS, Optional ByVal GotoNewline As Boolean = False) As Boolean
        If CurrentToken.Equals(Special) Then
            Accept = True
            NextToken()
        Else
            If GotoNewline Then Me.GotoNewline(True)
            Accept = False
        End If
    End Function

    ''' <summary>
    ''' If GotoNewline = true then calls GotoNewline(True) - next token is the first one after the newline.
    ''' </summary>
    ''' <param name="Special"></param>
    ''' <param name="GotoNewline"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Shared Function Accept(ByVal Reader As ITokenReader, ByVal Special As KS, Optional ByVal GotoNewline As Boolean = False) As Boolean
        If Reader.Peek.Equals(Special) Then
            Accept = True
            Reader.Next()
        Else
            If GotoNewline Then tm.GotoNewline(Reader, True)
            Accept = False
        End If
    End Function

    ''' <summary>
    ''' If GotoNewline = true then calls GotoNewline(True) - next token is the first one after the newline.
    ''' </summary>
    Function Accept(ByVal Identifier As String, Optional ByVal GotoNewline As Boolean = False) As Boolean
        If CurrentToken.Equals(Identifier) Then
            Accept = True
            NextToken()
        Else
            If GotoNewline Then Me.GotoNewline(True)
            Accept = False
        End If
    End Function

    Function AcceptAny(ByVal ParamArray Keywords() As KS) As Boolean
        Dim i As Integer
        For i = 0 To Keywords.Length - 1
            If Accept(Keywords(i)) Then
                Return True
            End If
        Next
        Return False
    End Function
    Function AcceptAll(ByVal ParamArray Specials() As KS) As Boolean
        Dim i As Integer
        AcceptAll = True
        For i = 0 To Specials.Length - 1
            AcceptAll = PeekToken(i).Equals(Specials(i)) AndAlso AcceptAll
        Next
        If AcceptAll Then NextToken(Specials.Length)
    End Function
End Class