What does wāw principally do in jāʾa Zaydun wa-huwa musriʿun?

Wāw with Nominal Circumstantial Clauses: Omission, Inclusion and Disputed Cases

• Link the attendant state to the act of arriving
• Coordinate Zayd and huwa as two agents
• Introduce an independent answer to an implied question
• Make musriʿ a complete substitute