Function dataflow_types::plan::linear_to_mfp

pub fn linear_to_mfp(
    linear: LinearOperator, 
    typ: &RelationType
) -> MapFilterProject

Helper method to convert linear operators to MapFilterProject instances.

This method produces a MapFilterProject instance that first applies any predicates, and then introduces Datum::Dummy literals in columns that are not demanded. The RelationType is required so that we can fill in the correct type of Datum::Dummy.