textmodes/ispell.el: Experimental support for support debugging.

 * (ispell-create-debug-buffer): Create a `ispell-debug-buffer' debug
   buffer for ispell.
 * (ispell-print-if-debug): New function to print stuff to 
   `ispell-debug-buffer' if debugging is enabled.
 * (ispell-region, ispell-process-line): Use `ispell-print-if-debug' to
   show some debugging info.
 * (ispell-buffer-with-debug): New function that creates a debugging
   buffer and calls `ispell-buffer' with debugging enabled.  This is also 
   en example of a possible way to use this system.

2 files changed, 86 insertions, 22 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 1f1868745de..7470a0677b2 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -3,6 +3,16 @@
         * textmodes/ispell.el (ispell-region): Standard re-indent for better
         readability.
 
+        * textmodes/ispell.el: Experimental support for support debugging.
+        (ispell-create-debug-buffer): Create a `ispell-debug-buffer' debug
+        buffer for ispell.
+        (ispell-print-if-debug): New function to print stuff to
+        `ispell-debug-buffer' if debugging is enabled.
+        (ispell-region, ispell-process-line): Use `ispell-print-if-debug' to
+        show some debugging info.
+        (ispell-buffer-with-debug): New function that creates a debugging
+        buffer and calls `ispell-buffer' with debugging enabled.
+
 2012-11-06  Dmitry Antipov  <dmantipov@yandex.ru>
 
         * emacs-lisp/byte-opt.el (toplevel): Add compare-window-configurations,
diff --git a/lisp/textmodes/ispell.el b/lisp/textmodes/ispell.el
index 0af619ce773..424a83c1713 100644
--- a/lisp/textmodes/ispell.el
+++ b/lisp/textmodes/ispell.el
@@ -907,6 +907,24 @@ Otherwise returns the library directory name, if that is defined."
       (setq default-directory (expand-file-name "~/")))
     (apply 'call-process-region args)))
 
+(defun ispell-create-debug-buffer (&optional append)
+  "Create an ispell debug buffer for debugging output.
+Use APPEND to append the info to previous buffer if exists,
+otherwise is reset.  Returns name of ispell debug buffer.
+See `ispell-buffer-with-debug' for an example of use."
+  (let ((ispell-debug-buffer (get-buffer-create "*ispell-debug*")))
+    (with-current-buffer ispell-debug-buffer
+      (if append
+          (insert
+           (format "-----------------------------------------------\n"))
+        (erase-buffer)))
+    ispell-debug-buffer))
+
+(defsubst ispell-print-if-debug (string)
+  "Print STRING to `ispell-debug-buffer' buffer if enabled."
+  (if (boundp 'ispell-debug-buffer)
+      (with-current-buffer ispell-debug-buffer
+        (insert string))))
 
 
 ;; The preparation of the menu bar menu must be autoloaded
@@ -2902,14 +2920,15 @@ amount for last line processed."
   (if (not recheckp)
       (ispell-accept-buffer-local-defs)) ; set up dictionary, local words, etc.
   (let ((skip-region-start (make-marker))
-        (rstart (make-marker)))
+        (rstart (make-marker))
+        (region-type (if (and (= reg-start (point-min)) (= reg-end (point-max)))
+                         (buffer-name) "region"))
+        (program-basename (file-name-nondirectory ispell-program-name))
+        (dictionary (or ispell-current-dictionary "default")))
     (unwind-protect
         (save-excursion
           (message "Spell-checking %s using %s with %s dictionary..."
-                   (if (and (= reg-start (point-min)) (= reg-end (point-max)))
-                       (buffer-name) "region")
-                   (file-name-nondirectory ispell-program-name)
-                   (or ispell-current-dictionary "default"))
+                   region-type program-basename dictionary)
           ;; Returns cursor to original location.
           (save-window-excursion
             (goto-char reg-start)
@@ -2917,18 +2936,30 @@ amount for last line processed."
                   (case-fold-search case-fold-search)
                   (query-fcc t)
                   in-comment key)
-              (let (message-log-max)
-                (message "searching for regions to skip"))
+              (ispell-print-if-debug
+               (concat
+                (format
+                 "ispell-region: (ispell-skip-region-list):\n%s\n"
+                 (ispell-skip-region-list))
+                (format
+                 "ispell-region: (ispell-begin-skip-region-regexp):\n%s\n"
+                 (ispell-begin-skip-region-regexp))
+                "ispell-region: Search for first region to skip after (ispell-begin-skip-region-regexp)\n"))
               (if (re-search-forward (ispell-begin-skip-region-regexp) reg-end t)
                   (progn
                     (setq key (match-string-no-properties 0))
                     (set-marker skip-region-start (- (point) (length key)))
-                    (goto-char reg-start)))
-              (let (message-log-max)
-                (message
-                 "Continuing spelling check using %s with %s dictionary..."
-                 (file-name-nondirectory ispell-program-name)
-                 (or ispell-current-dictionary "default")))
+                    (goto-char reg-start)
+                    (ispell-print-if-debug
+                     (format "ispell-region: First skip: %s at (pos,line,column): (%s,%s,%s).\n"
+                             key
+                             (save-excursion (goto-char skip-region-start) (point))
+                             (line-number-at-pos skip-region-start)
+                             (save-excursion (goto-char skip-region-start) (current-column))))))
+              (ispell-print-if-debug
+               (format
+                "ispell-region: Continue spell-checking with %s and %s dictionary...\n"
+                program-basename dictionary))
               (set-marker rstart reg-start)
               (set-marker ispell-region-end reg-end)
               (while (and (not ispell-quit)
@@ -2961,7 +2992,13 @@ amount for last line processed."
                             (setq key (match-string-no-properties 0))
                             (set-marker skip-region-start
                                         (- (point) (length key)))
-                            (goto-char rstart))
+                            (goto-char rstart)
+                            (ispell-print-if-debug
+                             (format "ispell-region: Next skip: %s at (pos,line,column): (%s,%s,%s).\n"
+                                     key
+                                     (save-excursion (goto-char skip-region-start) (point))
+                                     (line-number-at-pos skip-region-start)
+                                     (save-excursion (goto-char skip-region-start) (current-column)))))
                         (set-marker skip-region-start nil))))
                 (setq reg-end (max (point)
                                    (if (marker-position skip-region-start)
@@ -2971,6 +3008,10 @@ amount for last line processed."
                        (ispell-end (min (point-at-eol) reg-end))
                        (string (ispell-get-line
                                 ispell-start ispell-end in-comment)))
+                  (ispell-print-if-debug
+                   (format
+                    "ispell-region: string pos (%s->%s), eol: %s, [in-comment]: [%s], [string]: [%s]\n"
+                    ispell-start ispell-end (point-at-eol) in-comment string))
                   (if in-comment                ; account for comment chars added
                       (setq ispell-start (- ispell-start (length in-comment))
                             in-comment nil))
@@ -3006,10 +3047,7 @@ amount for last line processed."
         ;; Only save if successful exit.
         (ispell-pdict-save ispell-silently-savep)
         (message "Spell-checking %s using %s with %s dictionary...done"
-                 (if (and (= reg-start (point-min)) (= reg-end (point-max)))
-                     (buffer-name) "region")
-                 (file-name-nondirectory ispell-program-name)
-                 (or ispell-current-dictionary "default"))))))
+                 region-type program-basename dictionary)))))
 
 
 (defun ispell-begin-skip-region-regexp ()
@@ -3256,10 +3294,19 @@ Returns the sum SHIFT due to changes in word replacements."
             ;; Alignment cannot be tracked and this error will occur when
             ;; `query-replace' makes multiple corrections on the starting line.
             (or (ispell-looking-at (car poss))
-                ;; This occurs due to filter pipe problems
-                (error (concat "Ispell misalignment: word "
-                               "`%s' point %d; probably incompatible versions")
-                       (car poss) (marker-position word-start)))
+                ;; This error occurs due to filter pipe problems
+                (let* ((ispell-pipe-word (car poss))
+                       (actual-point (marker-position word-start))
+                       (actual-line (line-number-at-pos actual-point))
+                       (actual-column (save-excursion (goto-char actual-point) (current-column))))
+                  (ispell-print-if-debug
+                   (concat
+                    "ispell-process-line: Ispell misalignment error:\n"
+                    (format "  [Word from ispell pipe]: [%s], actual (point,line,column): (%s,%s,%s)\n"
+                            ispell-pipe-word actual-point actual-line actual-column)))
+                  (error (concat "Ispell misalignment: word "
+                                 "`%s' point %d; probably incompatible versions")
+                         ispell-pipe-word actual-point)))
             ;; ispell-cmd-loop can go recursive & change buffer
             (if ispell-keep-choices-win
                 (setq replace (ispell-command-loop
@@ -3393,6 +3440,13 @@ Returns the sum SHIFT due to changes in word replacements."
   (interactive)
   (ispell-region (point-min) (point-max)))
 
+;;;###autoload
+(defun ispell-buffer-with-debug (&optional append)
+  "`ispell-buffer' with some output sent to `ispell-debug-buffer' buffer.
+Use APPEND to append the info to previous buffer if exists."
+  (interactive)
+  (let ((ispell-debug-buffer (ispell-create-debug-buffer append)))
+    (ispell-buffer)))
 
 ;;;###autoload
 (defun ispell-continue ()