// check dyadic ops and compute result type
void CheckDyadicType(Symbol sym, DataType datatype1, DataType datatype2, ref DataType datatype)
{
var joinop = sym.JoinOp;
if (datatype1 is DataTypeRelation && datatype2 is DataTypeRelation)
{
var cols = DataColumn.Merge(Symbol.ToMergeOp(joinop), datatype1.Heading.Columns, datatype2.Heading.Columns);
var dups = cols.GroupBy(c => c.Name).Where(g => g.Count() > 1).Select(g => g.Key).ToArray();
if (dups.Length > 0)
{
Parser.ParseError($"{sym.Name}: duplicate attribute: {dups.Join(",")}");
}
datatype = DataTypeRelation.Get(DataHeading.Create(cols));
}
else if (datatype1 is DataTypeTuple && datatype2 is DataTypeTuple)
{
var cols = DataColumn.Merge(Symbol.ToTupleOp(joinop), datatype1.Heading.Columns, datatype2.Heading.Columns);
var dups = cols.GroupBy(c => c.Name).Where(g => g.Count() > 1).Select(g => g.Key).ToArray();
if (dups.Length > 0)
{
Parser.ParseError($"{sym.Name}: duplicate attribute: {dups.Join(",")}");
}
datatype = DataTypeTuple.Get(DataHeading.Create(cols));
}
else
{
Parser.ParseError($"{sym.Name}: expected relational or tuple arguments");
}
}
public AstType RelType(AstType type)
{
if (!type.DataType.HasHeading)
{
Parser.ParseError("value has no heading");
}
return(new AstType {
DataType = DataTypeRelation.Get(type.DataType.Heading)
});
}
internal DataType Relof(DataHeading heading)
{
return(DataTypeRelation.Get(heading));
}
internal DataType Relof(DataType type)
{
return(DataTypeRelation.Get(type.Heading));
}
internal DataType Find(IEnumerable <DataColumn> columns)
{
return(DataTypeRelation.Get(DataHeading.Create(columns)));
}