Module Tp5::ExtendRelateFirst

Maps the set of first values in the set of tuples that satisfy the given predicate, against a mapper function, and use the result to add a column to this tuple set.

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

Example:

predicate employs(Company company, Person person) { ... }
Address hasAddress(Person p) { ... }

// Selects (company, person, age) for all employed people.
import Tp2<Company, Person, employs/2>
  ::ExtendRelateSecond<getAge/1>
  ::Query