Commit 61a4b57f authored by Artur Malabarba's avatar Artur Malabarba

* lisp/character-fold.el: Add back multi-char matching

(character-fold-to-regexp): Uncomment recently commented code
and make the algorithm "dummer" by not checking every possible
combination.  This will miss some possible matches, but it
greatly reduces regexp size.

* test/automated/character-fold-tests.el
(character-fold--test-fold-to-regexp): Comment out test of
functionality no longer supported.
parent 13258026
......@@ -180,43 +180,49 @@ from which to start."
(regexp-quote (string c))))
(alist nil))
;; Long string. The regexp would probably be too long.
;; (unless (> end 50)
;; (setq alist (aref multi-char-table c))
;; (when case-fold-search
;; (let ((other-c (aref lower-case-table c)))
;; (when (or (not other-c)
;; (eq other-c c))
;; (setq other-c (aref upper-case-table c)))
;; (when other-c
;; (setq alist (append alist (aref multi-char-table other-c)))
;; (setq regexp (concat "\\(?:" regexp "\\|"
;; (or (aref character-fold-table other-c)
;; (regexp-quote (string other-c)))
;; "\\)"))))))
(push (let ((alist-out '("\\)")))
(pcase-dolist (`(,suffix . ,out-regexp) alist)
(let ((len-suf (length suffix)))
(unless (> end 50)
(setq alist (aref multi-char-table c))
(when case-fold-search
(let ((other-c (aref lower-case-table c)))
(when (or (not other-c)
(eq other-c c))
(setq other-c (aref upper-case-table c)))
(when other-c
(setq alist (append alist (aref multi-char-table other-c)))
(setq regexp (concat "\\(?:" regexp "\\|"
(or (aref character-fold-table other-c)
(regexp-quote (string other-c)))
"\\)"))))))
(push (let ((matched-entries nil)
(max-length 0))
(dolist (entry alist)
(let* ((suffix (car entry))
(len-suf (length suffix)))
(when (eq (compare-strings suffix 0 nil
string (1+ i) (+ i 1 len-suf)
nil)
t)
;; FIXME: If N suffixes match, we "branch"
;; out into N+1 executions for the rest of
;; the string. This involves redundant
;; work and makes a huge regexp.
(push (concat "\\|" out-regexp
(character-fold-to-regexp
string nil (+ i 1 len-suf)))
alist-out))))
(push (cons len-suf (cdr entry)) matched-entries)
(setq max-length (max max-length len-suf)))))
;; If no suffixes matched, just go on.
(if (not (cdr alist-out))
(if (not matched-entries)
regexp
;; Otherwise, add a branch for the
;; no-suffix case, and stop the loop here.
(prog1 (apply #'concat "\\(?:" regexp
(character-fold-to-regexp string nil (1+ i))
alist-out)
(setq i end))))
;;; If N suffixes match, we "branch" out into N+1 executions for the
;;; length of the longest match. This means "fix" will match "fix" but
;;; not "fⅸ", but it's necessary to keep the regexp size from scaling
;;; exponentially. See https://lists.gnu.org/archive/html/emacs-devel/2015-11/msg02562.html
(let ((subs (substring string (1+ i) (+ i 1 max-length))))
;; `i' is still going to inc by 1 below.
(setq i (+ i max-length))
(concat
"\\(?:"
(mapconcat (lambda (entry)
(let ((length (car entry))
(suffix-regexp (cdr entry)))
(concat suffix-regexp
(character-fold-to-regexp subs nil length))))
`((0 . ,regexp) . ,matched-entries) "\\|")
"\\)"))))
out))))
(setq i (1+ i)))
(when (> spaces 0)
......
......@@ -93,7 +93,10 @@
(aset multi ?1 '(("2" . "yy")))
(character-fold--test-match-exactly "a1" "xx44" "99")
(character-fold--test-match-exactly "a12" "77" "xx442" "992")
(character-fold--test-match-exactly "a12" "xxyy")))
;; Support for this case is disabled. See function definition or:
;; https://lists.gnu.org/archive/html/emacs-devel/2015-11/msg02562.html
;; (character-fold--test-match-exactly "a12" "xxyy")
))
(provide 'character-fold-tests)
......
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