5 ms·

Lisp Idioms

• araxima 15y ago
  If you happen to know the sequence is a list then might as well (apply #'min '(1 2 3 4 5)) instead of (reduce #'min '(1 2 3 4 5)). I'm sure the author is aware of that, but a reader might get the impression that #'min can only take two arguments.
  • sedachv 15y ago
    Apply has the problem in that Common Lisp allows compilers to restrict the number of arguments passed to a function to a small value (specified by call-arguments-limit: http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/HyperSpec/Body/convar_call-a_uments-limit.html http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/HyperSpec...).
    • jpr 15y ago
      I'm not well versed in CLHS legalese, but don't &rest arguments count as one argument? One would suspect so since &rest is allowed to be not copied.
      • gchpaco 15y ago
        Even if it is you still have to cons up all those arguments whereas reduce doesn't.
  • deleted 15y ago
    [deleted]
• technomancy 15y ago
  Might be useful to mention that these are mostly specific to CL.
• aidenn0 15y ago
  His first accumulate misses what is to me the most obvious way: (defun accumulate-f (n) (let* ((end (list (next))) (n (1- n)) (start end)) (dotimes (_ n start) (rplacd end (cons (next) nil)) (setq end (cdr end)))))
• zachbeane 15y ago
  Gene Michael Stover wrote about Common Lisp as someone who hardly ever looked at anyone else's idiomatic use of the language. I was pretty bummed that he got published in Dr. Dobbs with some pretty awful CL code.