Return Statement Inside The Closures In The Functions

Regarding Groovy Categories:
Return statements inside the functions don't return anything if used in the "use" closures:





class TokenCategory3 {
    static String g(String self) {
        return 'hello'
    }
}
String f() {
    use(TokenCategory3) {
        assert 'a'.g() == 'hello'
        return 'a'.g()
    }
}
use(TokenCategory3) {
    assert 'a'.g() == 'hello'
}
assert f() == null

Note that the last line returns null, although there is a return statement in f().
To make f() return some value, the return statement should be outside the "use" closure:

String h() {
    String result
    use(TokenCategory3) {
        result = 'a'.g()
    }
    return result
}
assert h() == 'hello'