private static void ReadRootOpenParenthesys(ReadRootContext context)
{
if (context.Current is not null)
{
context.Current = ReadingError(context.Reader, context.Messages, MissingLogicalOperator);
context.ShouldReturnCurrent = true;
return;
}
context.Current = ReadRoot(context.Reader, context.Messages, true, false);
context.ShouldReturnCurrent = context.Current is null;
}
private static void ReadRootVariableOrConstant(ReadRootContext context)
{
if (context.Current is not null)
{
context.Current = ReadingError(context.Reader, context.Messages, MissingLogicalOperator);
context.ShouldReturnCurrent = true;
return;
}
context.Current = ReadCondition(context.Reader, context.Messages);
if (context.SingleCondition || context.Current is null)
{
context.ShouldReturnCurrent = true;
}
}
private static void ReadRootNot(ReadRootContext context)
{
if (context.Current is not null)
{
context.Current = ReadingError(context.Reader, context.Messages, MissingLogicalOperator);
context.ShouldReturnCurrent = true;
return;
}
var right = ReadRoot(context.Reader, context.Messages, false, true);
if (right is null)
{
context.Current = null;
context.ShouldReturnCurrent = true;
return;
}
context.Current = new NotCondition(right);
}
private static ICondition?ReadRoot(IWordReader reader, List <string> messages, bool allowCloseParenthesys, bool singleCondition)
{
if (!reader.Read())
{
messages.Add(UnexpectedExpressionEnd);
return(null);
}
var context = new ReadRootContext(reader, messages, allowCloseParenthesys, singleCondition);
do
{
switch (reader.WordType)
{
case WordType.Invalid:
return(ReadingError(reader, messages, InvalidToken));
case WordType.Variable:
case WordType.String:
case WordType.Number:
case WordType.Null:
ReadRootVariableOrConstant(context);
break;
case WordType.OpenParenthesys:
ReadRootOpenParenthesys(context);
break;
case WordType.CloseParenthesys:
ReadRootCloseParenthesys(context);
break;
case WordType.And:
ReadRootLogicalOperator(context, (l, r) => new AndCondition(l, r));
break;
case WordType.Or:
ReadRootLogicalOperator(context, (l, r) => new OrCondition(l, r));
break;
case WordType.Not:
ReadRootNot(context);
break;
default:
return(ReadingError(reader, messages, MisplacedKeyword));
}
if (context.ShouldReturnCurrent)
{
return(context.Current);
}
}while (reader.Read());
if (context.AllowCloseParenthesys || context.Current is null)
{
messages.Add(UnexpectedExpressionEnd);
return(null);
}
return(context.Current);
}
