Some Self ideas

Richard A. O'Keefe ok at
Mon Jan 22 03:36:07 UTC 2001

Mark van Gulik <ghoul6 at> wrote:
	Funny you should mention Lispers.  Most of them seem
	quite happy when expressions like "(car 'x)" return nil.

> (car 'x)

ERROR: car: Wrong type in arg1 x
;Evaluation took 0 mSec (0 in gc) 7 cells work, 31 bytes other
: (car 'x)
*** ERROR -- PAIR expected
(car 'x(
----------------Macintosh CL------------------------------------
? (car 'x)
> Error: value X is not of the expected type LIST.
> While executing: CAR
> Type Command-. to abort.
See the Restarts... menu for further choices
1 >

	Then again, they used the empty list to represent false.  It
	shortens the code, but at what expense?

Shortening the code was not the issue.  It goes back to McCarthy's
original papers.  Lisp was invented as a notation for talking about
meta-mathematics.  It just had atoms, pairs, and functions, and minimality
was a *theoretical* point.  Scheme is a Lisp by any definition other than
"Lisp == Common Lisp", and it distinguishes between () (empty list), #f
(false), and NIL (just some random symbol).

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