howdy guys,
if I have something like,
(set 'a '())
(push this a)
(push that a)
how can I do, instead,
(push this that a)
I'm not getting it to work.
Does append work?
(set 'a (append a (list this) (list that)))
- doesn't look quite as nice ...
(push "hello" a -1) perhpas?
You could write your own version of push -- mypush-- that would be used something like this:
Notice that I quote the stack (in this case 'a) to prevent it from being evaluated.
Something like this (this code doesn't work):
(let
( stack (last (args))
list-of-items (butlast (args))
)
;body of let
(dolist (item list-of-items)
(push item (eval stack)) )))
Since newLisp doesn't have the 'butlast' function (anybody got a good one?), I'll hack it together like this (this code works):
(let
( stack (last (args))
list-of-items (reverse (rest (reverse (args))))
)
;body of let
(dolist (item list-of-items)
(push item (eval stack) -1)) ))
I'm sure someone (Lutz?) will suggest improvements.
An alternate solution would use define-macro for a syntax more like the built-in 'push'.
Edit: I figured out that 'butlast' is easily defined with chop:
;; return all but last n (default 1) elements of list / chars of string
;;
(define (butlast list-or-string n)
(chop list-or-string (or n 1)) )
> (set 'a '())
()
> (set 'b '("this" "that"))
("this" "that")
> (map (fn(x) (push x a)) b)
("this" "that")
> a
("that" "this")
This will push every element in b onto a.