Re: Making sure I'm not checking email (or doing other things) too often

[Michael Heerdegen]

Marcin Borkowski <mbork@mbork.pl> writes:

> (defun create-stopwatch ()
>   "Return a closure which returns time (in seconds) since its
> last invocation every time it is called."
>   (let (last-invocation-time (current-time))
>     (lambda ()
>       (prog1
>         (time-to-seconds (time-subtract (current-time) last-invocation-time))
>       (setq last-invocation-time (current-time))))))
>
> I don't claim it to be better, but I noticed a strange phenomenon.  When
> I invoke the "stopwatch object" (closure, in fact) for the first time,
> I get negative result.  Why is that so?

Eehm, eh...looks like your let bindings are not what you intended...
Ask the byte compiler!


Regards,

Michael.