Using ispell/aspell to spell check camelcased words

Question

I need to spell check a large document containing many camelcased words. I want ispell or aspell to check if the individual words are spelled correctly.

So, in case of this word:

ScientificProgrezGoesBoink

I would love to have it suggest this instead:

ScientificProgressGoesBoink

Is there any way to do this? (And I mean, while running it on an Emacs buffer.) Note that I don't necessarily want it to suggest the complete alternative. However, if it understands that Progrez is not recognized, I would love to be able to replace that part at least, or add that word to my private dictionary, rather than including every camel-cased word into the dictionary.

Answer 1

I took @phils suggestions and dug around a little deeper. It turns out that if you get camelCase-mode and reconfigure some of ispell like this:

(defun ispell-get-word (following)
  (when following
    (camelCase-forward-word 1))
  (let* ((start (progn (camelCase-backward-word 1)
                       (point)))
         (end (progn (camelCase-forward-word 1)
                     (point))))
    (list (buffer-substring-no-properties start end)
          start end)))

then, in that case, individual camel cased words suchAsThisOne will actually be spell-checked correctly. (Unless you're at the beginning of a document -- I just found out.)

So this clearly isn't the fullblown solution, but at least it's something.

Answer 2

There is "--run-together" option in aspell. Hunspell can't check camelcased word.

If you read the code of aspell, you will find its algorithm actually does not split camelcase word into a list of sub-words. Maybe this algorithm is faster, but it will wrongly report word containing two character sub-word as typo. Don't waste time to tweak other aspell options. I tried and they didn't work.

So we got two problems:

1. aspell reports SOME camelcased words as typos

2. hunspell reports ALL camelcased words as typos

Solution to solve BOTH problems is to write our own predicate in Emacs Lisp.

Here is a sample predicate written for javascript:

(defun split-camel-case (word)
  "Split camel case WORD into a list of strings.
Ported from 'https://github.com/fatih/camelcase/blob/master/camelcase.go'."
  (let* ((case-fold-search nil)
         (len (length word))
         ;; ten sub-words is enough
         (runes [nil nil nil nil nil nil nil nil nil nil])
         (runes-length 0)
         (i 0)
         ch
         (last-class 0)
         (class 0)
         rlt)

    ;; split into fields based on class of character
    (while (< i len)
      (setq ch (elt word i))
      (cond
       ;; lower case
       ((and (>= ch ?a) (<= ch ?z))
        (setq class 1))
       ;; upper case
       ((and (>= ch ?A) (<= ch ?Z))
        (setq class 2))
       ((and (>= ch ?0) (<= ch ?9))
        (setq class 3))
       (t
        (setq class 4)))

      (cond
       ((= class last-class)
        (aset runes
              (1- runes-length)
              (concat (aref runes (1- runes-length)) (char-to-string ch))))
       (t
        (aset runes runes-length (char-to-string ch))
        (setq runes-length (1+ runes-length))))
      (setq last-class class)
      ;; end of while
      (setq i (1+ i)))

    ;; handle upper case -> lower case sequences, e.g.
    ;;     "PDFL", "oader" -> "PDF", "Loader"
    (setq i 0)
    (while (< i (1- runes-length))
      (let* ((ch-first (aref (aref runes i) 0))
             (ch-second (aref (aref runes (1+ i)) 0)))
        (when (and (and (>= ch-first ?A) (<= ch-first ?Z))
                   (and (>= ch-second ?a) (<= ch-second ?z)))
          (aset runes (1+ i) (concat (substring (aref runes i) -1) (aref runes (1+ i))))
          (aset runes i (substring (aref runes i) 0 -1))))
      (setq i (1+ i)))

    ;; construct final result
    (setq i 0)
    (while (< i runes-length)
      (when (> (length (aref runes i)) 0)
        (setq rlt (add-to-list 'rlt (aref runes i) t)))
      (setq i (1+ i)))
     rlt))

(defun flyspell-detect-ispell-args (&optional run-together)
  "If RUN-TOGETHER is true, spell check the CamelCase words.
Please note RUN-TOGETHER will make aspell less capable. So it should only be used in prog-mode-hook."
  ;; force the English dictionary, support Camel Case spelling check (tested with aspell 0.6)
  (let* ((args (list "--sug-mode=ultra" "--lang=en_US"))args)
    (if run-together
        (setq args (append args '("--run-together" "--run-together-limit=16"))))
    args))

;; {{ for aspell only, hunspell does not need setup `ispell-extra-args'
(setq ispell-program-name "aspell")
(setq-default ispell-extra-args (flyspell-detect-ispell-args t))
;; }}

;; ;; {{ hunspell setup, please note we use dictionary "en_US" here
;; (setq ispell-program-name "hunspell")
;; (setq ispell-local-dictionary "en_US")
;; (setq ispell-local-dictionary-alist
;;       '(("en_US" "[[:alpha:]]" "[^[:alpha:]]" "[']" nil ("-d" "en_US") nil utf-8)))
;; ;; }}

(defvar extra-flyspell-predicate '(lambda (word) t)
  "A callback to check WORD.  Return t if WORD is typo.")

(defun my-flyspell-predicate (word)
  "Use aspell to check WORD.  If it's typo return t."
  (let* ((cmd (cond
               ;; aspell: `echo "helle world" | aspell pipe`
               ((string-match-p "aspell$" ispell-program-name)
                (format "echo \"%s\" | %s pipe"
                        word
                        ispell-program-name))
               ;; hunspell: `echo "helle world" | hunspell -a -d en_US`
               (t
                (format "echo \"%s\" | %s -a -d en_US"
                        word
                        ispell-program-name))))
         (cmd-output (shell-command-to-string cmd))
         rlt)
    ;; (message "word=%s cmd=%s" word cmd)
    ;; (message "cmd-output=%s" cmd-output)
    (cond
     ((string-match-p "^&" cmd-output)
      ;; it's a typo because at least one sub-word is typo
      (setq rlt t))
     (t
      ;; not a typo
      (setq rlt nil)))
    rlt))

(defun js-flyspell-verify ()
  (let* ((case-fold-search nil)
         (font-matched (memq (get-text-property (- (point) 1) 'face)
                             '(js2-function-call
                               js2-function-param
                               js2-object-property
                               js2-object-property-access
                               font-lock-variable-name-face
                               font-lock-string-face
                               font-lock-function-name-face
                               font-lock-builtin-face
                               rjsx-text
                               rjsx-tag
                               rjsx-attr)))
         subwords
         word
         (rlt t))
    (cond
     ((not font-matched)
      (setq rlt nil))
     ;; ignore two character word
     ((< (length (setq word (thing-at-point 'word))) 2)
      (setq rlt nil))
     ;; handle camel case word
     ((and (setq subwords (split-camel-case word)) (> (length subwords) 1))
      (let* ((s (mapconcat (lambda (w)
                             (cond
                              ;; sub-word wholse length is less than three
                              ((< (length w) 3)
                               "")
                               ;; special characters
                              ((not (string-match-p "^[a-zA-Z]*$" w))
                               "")
                              (t
                               w))) subwords " ")))
        (setq rlt (my-flyspell-predicate s))))
     (t
      (setq rlt (funcall extra-flyspell-predicate word))))
    rlt))

(put 'js2-mode 'flyspell-mode-predicate 'js-flyspell-verify)

Or just use my new pacakge https://github.com/redguardtoo/wucuo