HTML export: Improved support for field alignment, including centering

* doc/org.texi: Document the <c> cookie.
* lisp/org-exp.el (org-store-forced-table-alignment):
(org-export-remove-special-table-lines): Allow the "c" cookie for
table alignment.
* lisp/org-html.el (org-export-table-header-tags):
(org-export-table-data-tags): Add another %s format for the alignment.
(org-export-html-table-align-individual-fields): New option.
(org-format-org-table-html): Implement field-by-field alignment and
support centering.
(org-format-table-table-html): Make sure the new table tag formats
don't break this function.
* lisp/org-table.el (org-table-cookie-line-p):
(org-table-align): Allow for the <c> cookie.
* lisp/org.el (org-set-font-lock-defaults): Allow for the <c> cookie.

doc/org.texi

@@ -1922,9 +1922,10 @@ on a per-file basis with:
 @end example
 
 If you would like to overrule the automatic alignment of number-rich columns
-to the right and of string-rich column to the left, you and use @samp{<r>} or
-@samp{<l>} in a similar fashion.  You may also combine alignment and field
-width like this: @samp{<l10>}.
+to the right and of string-rich column to the left, you and use @samp{<r>},
+@samp{c}@footnote{Centering does not work inside Emacs, but it does have an
+effect when exporting to HTML.} or @samp{<l>} in a similar fashion.  You may
+also combine alignment and field width like this: @samp{<l10>}.
 
 Lines which only contain these formatting cookies will be removed
 automatically when exporting the document.

lisp/org-exp.el

@@ -1776,19 +1776,19 @@ When it is nil, all comments will be removed."
 
 (defun org-store-forced-table-alignment ()
   "Find table lines which force alignment, store the results in properties."
-  (let (line)
+  (let (line cnt aligns)
     (goto-char (point-min))
-    (while (re-search-forward "|[ \t]*<[rl][0-9]*>[ \t]*|" nil t)
+    (while (re-search-forward "|[ \t]*<[lrc][0-9]*>[ \t]*|" nil t)
       ;; OK, this looks like a table line with an alignment cookie
       (org-if-unprotected
        (setq line (buffer-substring (point-at-bol) (point-at-eol)))
        (when (and (org-at-table-p)
 		  (org-table-cookie-line-p line))
 	 (setq cnt 0 aligns nil)
-	 (mapcar
+	 (mapc
 	  (lambda (x)
 	    (setq cnt (1+ cnt))
-	    (if (string-match "\\`<\\([lr]\\)" x)
+	    (if (string-match "\\`<\\([lrc]\\)" x)
 		(push (cons cnt (downcase (match-string 1 x))) aligns)))
 	  (org-split-string line "[ \t]*|[ \t]*"))
 	 (add-text-properties (org-table-begin) (org-table-end)
@@ -1810,7 +1810,7 @@ Also, store forcedalignment information found in such lines."
 		 (lambda (f)
 		   (or (= (length f) 0)
 		       (string-match
-			"\\`<\\([0-9]\\|[rl]\\|[rl][0-9]+\\)>\\'" f)))
+			"\\`<\\([0-9]\\|[lrc]\\|[lrc][0-9]+\\)>\\'" f)))
 		 (org-split-string ;; FIXME, can't we do without splitting???
 		  (buffer-substring (point-at-bol) (point-at-eol))
 		  "[ \t]*|[ \t]*")))))

lisp/org-html.el

@@ -400,17 +400,22 @@ borders and spacing."
   :group 'org-export-html
   :type 'string)
 
-(defcustom org-export-table-header-tags '("<th scope=\"%s\">" . "</th>")
+(defcustom org-export-table-header-tags '("<th scope=\"%s\"%s>" . "</th>")
   "The opening tag for table header fields.
 This is customizable so that alignment options can be specified.
-%s will be filled with the scope of the field, either row or col.
-See also the variable `org-export-html-table-use-header-tags-for-first-column'."
+The first %s will be filled with the scope of the field, either row or col.
+The second %s will be replaced by a style entry to align the field.
+See also the variable `org-export-html-table-use-header-tags-for-first-column'.
+See also the variable `org-export-html-table-align-individual-fields'."
   :group 'org-export-tables
   :type '(cons (string :tag "Opening tag") (string :tag "Closing tag")))
 
-(defcustom org-export-table-data-tags '("<td>" . "</td>")
+(defcustom org-export-table-data-tags '("<td%s>" . "</td>")
   "The opening tag for table data fields.
-This is customizable so that alignment options can be specified."
+This is customizable so that alignment options can be specified.
+The first %s will be filled with the scope of the field, either row or col.
+The second %s will be replaced by a style entry to align the field.
+See also the variable `org-export-html-table-align-individual-fields'."
   :group 'org-export-tables
   :type '(cons (string :tag "Opening tag") (string :tag "Closing tag")))
 
@@ -441,7 +446,13 @@ will give even lines the class \"tr-even\" and odd lines the class \"tr-odd\"."
 		  (string :tag "Specify")
 		  (sexp))))
 
-
+(defcustom org-export-html-table-align-individual-fields t
+  "Non-nil means attach style attributes for alignment to each table field.
+When nil, alignment will only be specified in the column tags, but this
+is ignored by some browsers (like Firefox, Safari).  Opera does it right
+though."
+  :group 'org-export-tables
+  :type 'boolean)
 
 (defcustom org-export-html-table-use-header-tags-for-first-column nil
   "Non-nil means format column one in tables with header tags.
@@ -1869,9 +1880,9 @@ lang=\"%s\" xml:lang=\"%s\">
 		    (delq nil (mapcar
 			       (lambda (x) (string-match "^[ \t]*|-" x))
 			       (cdr lines)))))
-
 	 (nline 0) fnum nfields i (cnt 0)
-	 tbopen line fields html gr colgropen rowstart rowend)
+	 tbopen line fields html gr colgropen rowstart rowend
+	 ali align aligns n)
     (setq caption (and caption (org-html-do-expand caption)))
     (when (and forced-aligns org-table-clean-did-remove-column)
     (setq forced-aligns
@@ -1899,23 +1910,26 @@ lang=\"%s\" xml:lang=\"%s\">
 	(push (concat rowstart
 		      (mapconcat
 		       (lambda (x)
-			 (setq i (1+ i))
+			 (setq i (1+ i) ali (format "@@align%03d@@" i))
 			 (if (and (< i nfields) ; make sure no rogue line causes an error here
 				  (string-match org-table-number-regexp x))
 			     (incf (aref fnum i)))
 			 (cond
 			  (head
 			   (concat
-			    (format (car org-export-table-header-tags) "col")
+			    (format (car org-export-table-header-tags)
+				    "col" ali)
 			    x
 			    (cdr org-export-table-header-tags)))
 			  ((and (= i 0) org-export-html-table-use-header-tags-for-first-column)
 			   (concat
-			    (format (car org-export-table-header-tags) "row")
+			    (format (car org-export-table-header-tags)
+				    "row" ali)
 			    x
 			    (cdr org-export-table-header-tags)))
 			  (t
-			   (concat (car org-export-table-data-tags) x
+			   (concat (format (car org-export-table-data-tags) ali)
+				   x
 				   (cdr org-export-table-data-tags)))))
 		       fields "")
 		      rowend)
@@ -1932,23 +1946,32 @@ lang=\"%s\" xml:lang=\"%s\">
       (push (mapconcat
 	     (lambda (x)
 	       (setq gr (pop org-table-colgroup-info)
-		     i (1+ i))
+		     i (1+ i)
+		     align (if (assoc i forced-aligns)
+			       (cdr (assoc (cdr (assoc i forced-aligns))
+					   '(("l" . "left") ("r" . "right")
+					     ("c" . "center"))))
+			     (if (> (/ (float x) nline)
+				    org-table-number-fraction)
+				 "right" "left")))
+	       (push align aligns)
 	       (format "%s<col align=\"%s\" />%s"
 		       (if (memq gr '(:start :startend))
 			   (prog1
-			       (if colgropen "</colgroup>\n<colgroup>" "<colgroup>")
+			       (if colgropen
+				   "</colgroup>\n<colgroup>"
+				 "<colgroup>")
 			     (setq colgropen t))
 			 "")
-		       (if (assoc i forced-aligns)
-			   (cdr (assoc (cdr (assoc i forced-aligns)) '(("l" . "left") ("r" . "right"))))
-			 (if (> (/ (float x) nline) org-table-number-fraction)
-			     "right" "left"))
+		       align
 		       (if (memq gr '(:end :startend))
 			   (progn (setq colgropen nil) "</colgroup>")
 			 "")))
 	     fnum "")
 	    html)
-      (if colgropen (setq html (cons (car html) (cons "</colgroup>" (cdr html)))))
+      (setq aligns (nreverse aligns))
+      (if colgropen (setq html (cons (car html)
+				     (cons "</colgroup>" (cdr html)))))
       ;; Since the output of HTML table formatter can also be used in
       ;; DocBook document, we want to always include the caption to make
       ;; DocBook XML file valid.
@@ -1956,6 +1979,18 @@ lang=\"%s\" xml:lang=\"%s\">
       (when label (push (format "<a name=\"%s\" id=\"%s\"></a>" label label)
 			html))
       (push html-table-tag html))
+    (setq html (mapcar
+		(lambda (x)
+		  (replace-regexp-in-string
+		   "@@align\\([0-9]+\\)@@"
+		   (lambda (txt)
+		     (if (not org-export-html-table-align-individual-fields)
+			 ""
+		       (setq n (string-to-number (match-string 1 txt)))
+		       (format " style=\"text-align:%s\""
+			       (or (nth n aligns) "left"))))
+		   x))
+		html))
     (concat (mapconcat 'identity html "\n") "\n")))
 
 (defun org-export-splice-attributes (tag attributes)
@@ -2000,10 +2035,10 @@ But it has the disadvantage, that no cell- or row-spanning is allowed."
 			 (if (equal x "") (setq x empty))
 			 (if head
 			     (concat
-			      (format (car org-export-table-header-tags) "col")
+			      (format (car org-export-table-header-tags) "col" "")
 			      x
 			      (cdr org-export-table-header-tags))
-			   (concat (car org-export-table-data-tags) x
+			   (concat (format (car org-export-table-data-tags) "") x
 				   (cdr org-export-table-data-tags))))
 		       field-buffer "\n")
 		      "</tr>\n"))

lisp/org-latex.el

@@ -1277,7 +1277,7 @@ OPT-PLIST is the options plist for current buffer."
        (plist-get opt-plist :latex-header-extra)))
      ;; append another special variable
      (org-export-apply-macros-in-string org-export-latex-append-header)
-     ;; define align if not yet defined
+     ;; define alert if not yet defined
      "\n\\providecommand{\\alert}[1]{\\textbf{#1}}"
      ;; insert the title
      (format

lisp/org-table.el

@@ -342,19 +342,18 @@ available parameters."
 
 (defun org-table-cookie-line-p (line)
   "Is this a table line with only alignment/width cookies?"
-
   (save-match-data
     (and (string-match "[<>]\\|&[lg]t;" line)
 	 (or (string-match
-	      "\\`[ \t]*|[ \t]*/[ \t]*\\(|[ \t<>0-9|lgt&;]+\\)\\'" line)
-	     (string-match "\\(\\`[ \t<>lr0-9|gt&;]+\\'\\)" line))
+	      "\\`[ \t]*|[ \t]*/[ \t]*\\(|[ \t<>0-9|lrcgt&;]+\\)\\'" line)
+	     (string-match "\\(\\`[ \t<>lrc0-9|gt&;]+\\'\\)" line))
 	 (not (delq nil (mapcar
 			 (lambda (s)
 			   (not (or (equal s "")
 				    (string-match
-				     "\\`<\\([lr]?[0-9]+\\|[lr]\\)>\\'" s)
+				     "\\`<\\([lrc]?[0-9]+\\|[lrc]\\)>\\'" s)
 				    (string-match
-				     "\\`&lt;\\([lr]?[0-9]+\\|[lr]\\)&gt;\\'"
+				     "\\`&lt;\\([lrc]?[0-9]+\\|[lrc]\\)&gt;\\'"
 				     s))))
 			 (org-split-string (match-string 1 line)
 					   "[ \t]*|[ \t]*")))))))
@@ -662,9 +661,9 @@ When nil, simply write \"#ERROR\" in corrupted fields.")
     (goto-char beg)
     (setq narrow (and org-table-do-narrow
 		      org-format-transports-properties-p
-		      (re-search-forward "<[rl]?[0-9]+>" end t)))
+		      (re-search-forward "<[lrc]?[0-9]+>" end t)))
     (goto-char beg)
-    (setq falign (re-search-forward "<[rl][0-9]*>" end t))
+    (setq falign (re-search-forward "<[lrc][0-9]*>" end t))
     (goto-char beg)
     ;; Get the rows
     (setq lines (org-split-string
@@ -705,7 +704,7 @@ When nil, simply write \"#ERROR\" in corrupted fields.")
 	(setq c column fmax nil falign1 nil)
 	(while c
 	  (setq e (pop c))
-	  (when (and (stringp e) (string-match "^<\\([rl]\\)?\\([0-9]+\\)?>$" e))
+	  (when (and (stringp e) (string-match "^<\\([lrc]\\)?\\([0-9]+\\)?>$" e))
 	    (if (match-end 1) (setq falign1 (match-string 1 e)))
 	    (if (and org-table-do-narrow (match-end 2))
 		(setq fmax (string-to-number (match-string 2 e)) c nil))))

lisp/org.el

@@ -5457,7 +5457,7 @@ needs to be inserted at a specific position in the font-lock sequence.")
 	   '("^[ \t]*|\\(?:.*?|\\)? *\\(:?=[^|\n]*\\)" (1 'org-formula t))
 	   '("^[ \t]*| *\\([#*]\\) *|" (1 'org-formula t))
 	   '("^[ \t]*|\\( *\\([$!_^/]\\) *|.*\\)|" (1 'org-formula t))
-	   '("| *\\(<[lr]?[0-9]*>\\)" (1 'org-formula t))
+	   '("| *\\(<[lrc]?[0-9]*>\\)" (1 'org-formula t))
 	   ;; Drawers
 	   (list org-drawer-regexp '(0 'org-special-keyword t))
 	   (list "^[ \t]*:END:" '(0 'org-special-keyword t))