Syntax
RECURSIVE SUBROUTINE sub-name([dummy-args])
RECURSIVE [type-spec] FUNCTION func-name([dummy-args])
    [RESULT(result-name)]
Where:
    sub-name is the name of the subroutine
    dummy-args is a comma-seperated list of dummy argument names
    type-spec is
        INTEGER [kind-selector] REAL [kind-selector] DOUBLE
        COMPLEX [kind-selector] CHARACTER [char-selector] LOGICAL [kind-selector]
        TYPE (type-name)
    kind-selector is ( [KIND=] kind)
    char-selector is ( [LEN=] length [, ) KIND=kind
    or (KIND=kind [, LEN=length]) or * char-length [,]
    kind is a scalar INTEGER expression or *
    char-length is a scalar INTEGER literal constant or (*)
    func-name is the name of the function.
    result-name is the name of the result variable