Why is Python popular, while Lisp and Scheme aren't?

[Michael Hudson]

maney at pobox.com writes:

> Michael Hudson <mwh at python.net> wrote:
> > come up with it.  Isn't there a pithy quote along the lines of
> > "constraints spark creativity"?
> 
> Form is liberating?  Though a slightly mangled old saw like "desperation is
> the mother of invention" seems more like what you're looking for.  :-)

Yeah, I thought about that one, but I sem to remember another
one... oh well, doesn't matter.

> > The only biggy for me is the lack of Lisp style (with-... ) macros;
> > which of these do you prefer:
> > 
> > def 
> 
> You got cutoff here, or the article got truncated on its way.  Want to try
> again?  I expect I'd enjoy seeing what you were going to say.

Ah yes, I went away to try and come up with a good example, got
distracted, and so on.

Consider this code from Python's getpass module:

    old = termios.tcgetattr(fd)     # a copy to save
    new = old[:]

    new[3] = new[3] & ~termios.ECHO # 3 == 'lflags'
    try:
        termios.tcsetattr(fd, termios.TCSADRAIN, new)
        passwd = _raw_input(prompt)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old)

In CL if you wanted to do this sort of thing often you'd write
something like (making up interface names as I go):

(defmacro with-invisible-input (fd &body body)
  (let ((old-state (gensym))
        (new-state (gensym)
        (fd-var (gensym)))
    `(let* ((,old-state (termios:tcgetattr ,fd))
            (,new-state (termios:copy-state ,old-state))
            (,fd-var ,fd))
       (setf (termios:lflags ,new-state) 
             (logior (termios:lflags ,new-state) termios:echo))
       (termios:tcsetattr ,fd-var ,new-state)
       (unwind-protect
         ,body
         (termios:tcsetattr ,fd-var ,old-state))))))

which isn't exactly pretty, but now the above Python becomes:

(with-invisible-input 
  (funcall input-func prompt))

which *is* better.

Cheers,
M.

-- 
  But since your post didn't lay out your assumptions, your goals,
  or how you view language characteristics as fitting in with 
  either, you're not a *natural* candidate for embracing Design by 
  Contract <0.6 wink>.    -- Tim Peters, giving Eiffel adoption advice