Richard Stallman <rms@gnu.org> writes:

>     So the job only has to be done once, what replacement will people
>     be happy with? Personally, I think plain "if" would be just fine,
>     except perhaps to the tediously literal-minded.
>
> In some cases, just "if" is clear.
>
>     Failing that, "only if".  As a last resort, "if and only if"
>     (yuck).
>
> Where just "if" is not clear, you need to get creative.  Find a
> rewrite which is clear.  "If and only if" is ok when you need it, but
> since it is a bit longer, you might look for a better method.

The conditionals "only if" and "if" are both unidirectional, whereas "if
and only if" is bidirectional.  If you want to preserve the logic, it is
best to change "iff" to "if and only if".  It's not nearly as gross as
changing the meaning would be.

-- 
       Michael Olson -- FSF Associate Member #652     |
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