9 Jan
2014
9 Jan
'14
11:13 a.m.
The other part is that in LISP, the operation is over
a list.
(+ 4 5 6 ) in LISP is not same as 4 5 6 + in Forth.
Yes. Lisp does not quite use (non-reverse) Polish notation; it
surrounds calls with parens so as to support variable-arity functions.
(For example, most Lisps support not only (+ 1 2) but (+ 1 2 3) and
(+ 4 5 6 7) and the like, whereas FORTH does the analog with 1 2 + and
1 2 3 + + and 4 5 6 7 + + +). If all Lisp operations had fixed arity,
the parens could in principle be omitted in code, though that would
have two problems: (1) they are useful enough to humans that it would
arguably be a good idea to provide them anyway for error checking and
(2) it would break homoiconicity to some extent - even if the +
function always takes exactly two args, the list (+ 1 2 3 4 5) still
makes sense as a list, just one that errors if evaluated.
/~\ The ASCII Mouse
\ / Ribbon Campaign
X Against HTML mouse at rodents-montreal.org
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B