A RETURN statement for a proper procedure has the form:
RETURN
The statement raises the return-exception without an argument. It
is allowed only in the body of a proper procedure.
A RETURN statement for a function procedure has the form:
RETURN Expr
where Expr is an expression assignable to the result type of
the procedure. The statement raises the return-exception with the
argument Expr. It is allowed only in the body of a function
procedure.
Failure to return a value from a function procedure is a checked runtime error.
The effect of raising the return exception is to terminate the current procedure activation. To be precise, a call on a proper procedure with body B is equivalent (after binding the arguments) to:
TRY B EXCEPT return-exception => (*skip*) END
A call on a function procedure with body B is equivalent to:
TRY
B; (error: no returned value)
EXCEPT
return-exception (v) => (the result becomes v)
END