Common Lisp 练习日常

渐渐能够写出越来越长的程序了😋

https://pastebin.com/NnAaGhrZ

CL-USER> (defstruct string-slice
           (string-data nil :type string)
           (begin-index 0 :type integer)
           (end-index nil :type integer))
STRING-SLICE
CL-USER> (defun string-split-by-char (ch str)
           (declare (type character ch)
                    (type string str)
                    (optimize (speed 3) (safety 1)))
           (let ((last-index 0)
                 (len (length str))
                 (result nil))
             (do ((i 0 (1+ i)))
                 ((>= i len)
                  (push (make-string-slice :string-data str
                                           :begin-index last-index
                                           :end-index i)
                        result)
                  (nreverse result))
               (if (eql ch (char str i))
                   (progn (push (make-string-slice :string-data str
                                             :begin-index last-index
                                             :end-index i)
                                result)
                          (setf last-index (1+ i)))))))
STRING-SPLIT-BY-CHAR
CL-USER> (string-split-by-char #\Space "To be, or not to be")
(#S(STRING-SLICE
    :STRING-DATA "To be, or not to be"
    :BEGIN-INDEX 0
    :END-INDEX 2)
 #S(STRING-SLICE
    :STRING-DATA "To be, or not to be"
    :BEGIN-INDEX 3
    :END-INDEX 6)
 #S(STRING-SLICE
    :STRING-DATA "To be, or not to be"
    :BEGIN-INDEX 7
    :END-INDEX 9)
 #S(STRING-SLICE
    :STRING-DATA "To be, or not to be"
    :BEGIN-INDEX 10
    :END-INDEX 13)
 #S(STRING-SLICE
    :STRING-DATA "To be, or not to be"
    :BEGIN-INDEX 14
    :END-INDEX 16)
 #S(STRING-SLICE
    :STRING-DATA "To be, or not to be"
    :BEGIN-INDEX 17
    :END-INDEX 19))
CL-USER> (defun slice-to-string (slice)
           (declare (type string-slice slice)
                    (optimize (speed 3) (safety 1)))
           (subseq (string-slice-string-data slice)
                   (string-slice-begin-index slice)
                   (string-slice-end-index slice)))
SLICE-TO-STRING
CL-USER> (mapcar #'slice-to-string
                 (string-split-by-char #\Space "To be, or not to be"))
("To" "be," "or" "not" "to" "be")
CL-USER>