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.
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 operators (e.g. -= became =-) was eventually repealed in C.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@ccil.org
If I have not seen as far as others, it is because giants were standing
on my shoulders. --Hal Abelson