Pass leading and trailing tab characters in paragraph formatting.

ansi.scm

@@ -149,25 +149,41 @@
    (irregex-replace/all (irregex "\x1b\\[[0-9;]*[^0-9;]" 'u) str ""))
 
  ;; Formats string as paragraph of maximum given width while removing
- ;; all ANSI CSI SGR from it.
+ ;; all ANSI CSI SGR from it. If the first character is \t, align
+ ;; right, if both first and last characters are \t, align center. The
+ ;; alignment is not done here, but the \t are added to all lines
+ ;; accordingly.
  (define (ansi-paragraph-format str width)
-   (let loop ((words (string-split
-		      (ansi-remove str)))
-	      (res '("")))
-     (if (null? words)
-	 (string-intersperse (reverse res) "\n")
-	 (let* ((word (car words))
-		(wlen (ansi-string-length word))
-		(llen (ansi-string-length (car res))))
-	   (loop (cdr words)
-		 (if (> (+ llen wlen 1) width)
-		     (cons word res)
-		     (cons (string-append (car res)
-					  (if (eq? (string-length (car res)) 0)
-					      ""
-					      " ")
-					  word)
-			   (cdr res))))))))
+   (let* ((strl (string->list str))
+	  (first-char (car strl))
+	  (last-char (car (reverse strl)))
+	  (first-tab (eq? first-char #\tab))
+	  (last-tab (eq? last-char #\tab)))
+     (let loop ((words (string-split
+			(ansi-remove str)))
+		(res '("")))
+       (if (null? words)
+	   (string-intersperse
+	    (reverse
+	     (map
+	      (lambda (line)
+		(string-append (if first-tab "\t" "")
+			       line
+			       (if last-tab "\t" "")))
+	      res))
+	    "\n")
+	   (let* ((word (car words))
+		  (wlen (ansi-string-length word))
+		  (llen (ansi-string-length (car res))))
+	     (loop (cdr words)
+		   (if (> (+ llen wlen 1) width)
+		       (cons word res)
+		       (cons (string-append (car res)
+					    (if (eq? (string-length (car res)) 0)
+						""
+						" ")
+					    word)
+			     (cdr res)))))))))
 
  ;; Returns a concatenation of all ANSI styles specified by this
  ;; module