checking if a list is empty

[Roy Smith]

In article <mailman.1549.1305383294.9059.python-list at python.org>,
 David Robinow <drobinow at gmail.com> wrote:

> On Fri, May 13, 2011 at 10:34 PM, Gregory Ewing
> <greg.ewing at canterbury.ac.nz> wrote:
> > rusi wrote:
> >
> >> Dijkstra's problem (paraphrased) is that python, by choosing the
> >> FORTRAN alternative of having a non-first-class boolean type, hinders
> >> scientific/mathematical thinking/progress.
> >
> > Python doesn't have the flaw that Dijkstra was talking about.
> > Fortran's flaw wasn't so much the lack of a boolean type, but
> > that you couldn't assign the result of a logical expression to
> > a variable. Python has always been able to do that, even before
> > it had a distinct boolean type.
> And Fortran could do it at least 25 years before Python was invented.

I vaguely remember that Fortran called the data type LOGICAL, but yes, 
it was exactly what most modern languages call a bool or boolean.  And 
the operators were spelled .NOT., .AND., .OR., etc but that's because 
Fortran was designed for punch cards, which didn't have much in the way 
of special characters.