module ProjectM36.AttributeNames where import ProjectM36.Base import qualified Data.Set as S --AttributeNames is a data structure which can represent inverted projection attributes and attribute names derived from relational expressions empty :: AttributeNamesBase a empty :: forall a. AttributeNamesBase a empty = forall a. Set AttributeName -> AttributeNamesBase a AttributeNames forall a. Set a S.empty all :: AttributeNamesBase a all :: forall a. AttributeNamesBase a all = forall a. Set AttributeName -> AttributeNamesBase a InvertedAttributeNames forall a. Set a S.empty