Lisp - Splitting Input into Separate Strings

Question

I'm trying to take user input and storing it in a list, only instead of a list consisting of a single string, I want each word scanned in to be its own string. Example:

> (input)
This is my input. Hopefully this works

would return:

("this" "is" "my" "input" "hopefully" "this" "works")

Taking note that I don't want any spaces or punctuation in my final list.

Any input would be greatly appreciated.

Answer 1

split-sequence is the off-the-shelf solution.

you can also roll your own:

(defun my-split (string &key (delimiterp #'delimiterp))
  (loop :for beg = (position-if-not delimiterp string)
    :then (position-if-not delimiterp string :start (1+ end))
    :for end = (and beg (position-if delimiterp string :start beg))
    :when beg :collect (subseq string beg end)
    :while end))

where delimiterp checks whether you want to split on this character, e.g.

(defun delimiterp (c) (or (char= c #\Space) (char= c #\,)))

or

(defun delimiterp (c) (position c " ,.;/"))

PS. looking at your expected return value, you seem to want to call string-downcase before my-split.

PPS. you can easily modify my-split to accept :start, :end, :delimiterp &c.

PPPS. Sorry about bugs in the first two versions of my-split. Please consider that an indicator that one should not roll one's own version of this function, but use the off-the-shelf solution.