- Define an expect(index, actual_value, types...) helper function which
takes an argument index, value and list of permissable types and
ensures the value is of one of those types.
If not, it will produce an error message with the expected and actual
type, as well as the argument number and (if available) the function
name.
- Expose expect in the global scope as _G["~expect"], hopefully making
it clear it is internal.
- Replace most manual type checks with this helper method.
- Write tests to ensure this argument validation works as expected
Also fix a couple of bugs exposed by this refactor and the subsequent
tests:
- Make rednet checks a little more strict - rednet.close(false) is no
longer valid.
- Error when attempting to redirect the terminal to itself
(term.redirect(term)).