9 Mar
2016
9 Mar
'16
1:10 a.m.
How were they spelled in Lisp 1.5? The manual lists add1 and sub1, but says
nothing about them modifying the value of a variable.
Sent from my phone. Please excuse my brevity.
On Mar 8, 2016 10:20 AM, "John Cowan" <cowan(a)mercury.ccil.org> wrote:
Doug McIlroy scripsit:
Various aspects of the language were borrowed
from PL/I, BCPL and Algol
68. ++ and -- were novel operators. The reversal of Algol's assignment
operators (e.g. -= became =-) was eventually repealed in C.
Algol 68, like Algol 60 and Pascal, used := (pronounced "becomes") for
assignment, and the Algol 68 assignment operators were spelled :+=,
:-=, etc. (pronounced "plus and becomes", "minus and becomes", etc.)
Pre-increment operators were already known in Lisp 1.5 long before;
they are now spelled incf and decf in Common Lisp.
--
John Cowan http://www.ccil.org/~cowan cowan(a)ccil.org
If I have not seen as far as others, it is because giants were standing
on my shoulders. --Hal Abelson