Czajnikowski

let fetchRequest = NSFetchRequest<Contact>(
  entityName: Contact.entity().name!
)

fetchRequest.predicate = NSCompoundPredicate(
  orPredicateWithSubpredicates: [
    "name",
    "surname",
    "city"
    ]

Czajnikowski

public class Contact: NSManagedObject {
  @NSManaged public var name: String
  @NSManaged public var surname: String
  @NSManaged public var addresses: Set<Address>
}

public class Address: NSManagedObject {
  @NSManaged public var city: String
}

Czajnikowski

let contacts: [Contact] = …

var results = [Contact]()
for contact in contacts {
  var addressesMatchingQuery = [Address]()
  for address in contact.addresses {
    if address.city == searchQuery {
      addressesMatchingQuery.append(address)
    }
  }

Czajnikowski

let contacts: [Contact] = …

let results = contacts.filter { contact in
  var addressesMatchingQuery = [Address]()
  for address in contact.addresses {
    if address.city == searchQuery {
      addressesMatchingQuery.append(address)
    }
  }

Czajnikowski

let contacts: [Contact] = …

let results = contacts.filter { contact in
  let addressesMatchingQuery = contact.addresses.filter { address in
    address.city == searchQuery
  }

  return addressesMatchingQuery.count > 0
}

Czajnikowski

let contacts: [Contact] = …

let results = contacts.filter { contact in
  contact.addresses.filter { address in
    address.city == searchQuery
  }.count > 0
}

Czajnikowski

"SUBQUERY(addresses, $address, $address.city ==[cd] \"\(searchQuery)\").@count > 0"

Czajnikowski

reduce(initialValue) {
  ...
  if resultIsGoodEnough($0) {
    break // and return current $0
  }
}

Czajnikowski

reduce(initialValue) {
  ...
  if resultIsGoodEnough($0) {
    return $0 //  No break here!
  } 
}

Czajnikowski

reduce(
  initialValue,
  { ... },
  until: resultIsGoodEnough
)