private Token ReadNext()
{
Char firstChar = m_buffer.Current;
if (ProgramLine.EndOfField(firstChar))
{
return(Token.MakeEndOfToken());
}
else if (firstChar == Casl2Defs.Comma)
{
m_buffer.MoveNext();
return(Token.MakeComma());
}
else if (firstChar == Casl2Defs.EqualSign)
{
m_buffer.MoveNext();
return(Token.MakeEqualSign());
}
else if (DecimalConstant.IsStart(firstChar))
{
Int32 i32Value = DecimalConstant.Read(m_buffer);
return(Token.MakeDecimalConstant(i32Value));
}
else if (HexaDecimalConstant.IsStart(firstChar))
{
Int32 i32Value = HexaDecimalConstant.Read(m_buffer);
return(Token.MakeHexaDecimalConstant(i32Value));
}
else if (StringConstant.IsStart(firstChar))
{
String strValue = StringConstant.Read(m_buffer);
return(Token.MakeStringConstant(strValue));
}
else if (Label.IsStart(firstChar))
{
// ラベルはレジスタ名の場合もある。オペランドの字句要素の区切りまで読み込む。
String strValue = Operand.ReadItem(m_buffer);
if (ProgramRegister.IsRegisterName(strValue))
{
return(Token.MakeRegisterName(strValue));
}
else
{
return(Token.MakeLabel(strValue));
}
}
else
{
String message = String.Format(Resources.MSG_CouldNotParseAsToken, firstChar);
throw new Casl2SimulatorException(message);
}
}
private static Boolean EndOfItem(Char current)
{
return(ProgramLine.EndOfField(current) || current == Casl2Defs.Comma);
}
