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Don't mutate strings in cl-substitute

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This fixes cl-substitute, cl-substitute-if, cl-substitute-if-not,
cl-nsubstitute, cl-nsubstitute-if and cl-nsubstitute-if-not,
when called with a string sequence argument.

* lisp/emacs-lisp/cl-seq.el (cl-nsubstitute):
Avoid running in O(n^2) time and make future-safe.
This commit is contained in:
Mattias Engdegård 2024-05-08 12:13:48 +02:00
parent b82a003544
commit de5a89254c
1 changed files with 5 additions and 4 deletions
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9
lisp/emacs-lisp/cl-seq.el
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@ -452,14 +452,15 @@ to avoid corrupting the original SEQ.
(apply 'cl-substitute cl-new nil cl-list :if-not cl-pred cl-keys))
;;;###autoload
(defun cl-nsubstitute (cl-new cl-old cl-seq &rest cl-keys)
(defun cl-nsubstitute (cl-new cl-old seq &rest cl-keys)
"Substitute NEW for OLD in SEQ.
This is a destructive function; it reuses the storage of SEQ whenever possible.
\nKeywords supported: :test :test-not :key :count :start :end :from-end
\n(fn NEW OLD SEQ [KEYWORD VALUE]...)"
(cl--parsing-keywords (:test :test-not :key :if :if-not :count
(:start 0) :end :from-end) ()
(let ((len (length cl-seq)))
(let* ((cl-seq (if (stringp seq) (string-to-vector seq) seq))
(len (length cl-seq)))
(or (eq cl-old cl-new) (<= (or cl-count (setq cl-count len)) 0)
(if (and (listp cl-seq) (or (not cl-from-end) (> cl-count (/ len 2))))
(let ((cl-p (nthcdr cl-start cl-seq)))
@ -483,8 +484,8 @@ This is a destructive function; it reuses the storage of SEQ whenever possible.
(progn
(aset cl-seq cl-start cl-new)
(setq cl-count (1- cl-count))))
(setq cl-start (1+ cl-start)))))))
cl-seq))
(setq cl-start (1+ cl-start))))))
(if (stringp seq) (concat cl-seq) cl-seq))))
;;;###autoload
(defun cl-nsubstitute-if (cl-new cl-pred cl-list &rest cl-keys)