Module Tp6::MapRelateFirst

Maps the set of first values in the set of tuples that satisfy the given predicate, against a mapper relation.

Sibling function of MapFirst, which operates on “functions” instead of “relations.”

Example:

predicate employs(Company company, Person person) { ... }
Pet getPets(Person p) { ... }

// Selects the pets of employed People.
select Tp2<Company, Person, employs/2>
  ::MapRelateSecond<Pet, getPets/1>
  ::find()