public RowParserResult <T> Parse(TRow row)
{
try
{
return(_parser(row));
}
catch (Exception ex)
{
return(RowParserResult.Failed <T>(ex));
}
}
private static RowParser <T, IDataRecord> Simple <T>(int col, Func <IDataRecord, T> f)
{
return(new RowParser <T, IDataRecord>(row =>
{
if (row.IsDBNull(col))
{
return RowParserResult.Failed <T>(UnexpectedNullFieldException.UnexpectedNull);
}
return RowParserResult.Successful(f(row));
}));
}
public static RowParser <IMaybe <T>, IDataRecord> Optional <T>(RowParser <T, IDataRecord> other)
{
return(new RowParser <IMaybe <T>, IDataRecord>(row =>
{
return other.Parse(row).Map(Maybe.Just).Recover(ex =>
{
if (ex == UnexpectedNullFieldException.UnexpectedNull)
{
return RowParserResult.Successful(Maybe.Nothing <T>());
}
return RowParserResult.Failed <IMaybe <T> >(ex);
});
}));
}
public static RowParser <T, IDataRecord> Named <T>(string name, Func <int, RowParser <T, IDataRecord> > byIndexParser)
{
return(new RowParser <int, IDataRecord>(row => RowParserResult.Successful(row.GetOrdinal(name)))
.FlatMap(byIndexParser));
}