Definitions for "Function declaration"
a full statement in PSource, so it should be terminated by a comma
a sequence of function clauses separated by semicolons, and terminated by period (
a single statement that informs your compiler that a function will be defined later, and should be usable immediately
a contract between the implementer and the users of the function, and making exceptions a part of this contract means that a user has more information how the function will interact with his code