Re: %(~cut X) is broken

[Martin Kretzschmar <Martin.Kretzschmar@inf.tu-dresden.de>]

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Neal H Walfield <neal@cs.uml.edu> writes:

[snip]
> As you can see, %~(cut 3)d is only printing out `Se' when all I am
> doing is asking it to cut off the first three characters (which, it
> does do quite well, but, Gnus does not need to be so generous).

This is a problem in gnus-correct-substring. It will never include the
last character in a substring. Here's a patch to fix that:


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--- /tmp/gnus-spec.el	Thu Sep 13 18:23:30 2001
+++ /tmp/gnus-spec.el.new	Thu Sep 13 18:23:30 2001
@@ -273,20 +273,21 @@
 (defun gnus-correct-substring (string start &optional end)
   (let ((wstart 0)
 	(wend 0)
+	(wseek 0)
 	(seek 0)
-	(length (length string)))
+	(length (length string))
+	(string (concat string "\0"))) 
     ;; Find the start position.
     (while (and (< seek length)
-		(< wstart start))
-      (incf wstart (gnus-char-width (aref string seek)))
+		(< wseek start))
+      (incf wseek (gnus-char-width (aref string seek)))
       (incf seek))
-    (setq wend wstart
-	  wstart seek)
+    (setq wstart seek)
     ;; Find the end position.
-    (while (and (< seek length)
+    (while (and (<= seek length)
 		(or (not end)
-		    (<= wend end)))
-      (incf wend (gnus-char-width (aref string seek)))
+		    (<= wseek end)))
+      (incf wseek (gnus-char-width (aref string seek)))
       (incf seek))
     (setq wend seek)
     (substring string wstart (1- wend))))

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Is this too ugly or even buggy?

Looking at gnus-tilde-cut-form, I found another bug, a "," is missing,
in gnus-tilde-max-form, too, try this:

   (gnus-tilde-max-form 'bla -3) or, more high-level
   "%~(cut-right 3)L" as gnus-summary-line-format

Not only does the following patch insert the ",", it also make the
functions more readable than they were in the last weeks (IMO). If you
don't trust them, please insert at least the two ",".


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--- /tmp/gnus-spec.el2052Buh	Thu Sep 13 18:58:06 2001
+++ /tmp/gnus-spec.el.new2052O4n	Thu Sep 13 18:58:06 2001
@@ -293,74 +293,46 @@
 
 (defun gnus-tilde-max-form (el max-width)
   "Return a form that limits EL to MAX-WIDTH."
-  (let ((max (abs max-width)))
-    (if (symbolp el)
-	`(if (> (,(if gnus-use-correct-string-widths
+  (let ((max (abs max-width))
+	(length-fun (if gnus-use-correct-string-widths
 		      'gnus-correct-length
-		    'length) ,el)
-		,max)
-	     ,(if (< max-width 0)
-		  `(,(if gnus-use-correct-string-widths
-			 'gnus-correct-substring
-		       'substring)
-		    ,el (- (,(if gnus-use-correct-string-widths
-				 'gnus-correct-length
-			       'length)
-			    el) ,max))
-		`(,(if gnus-use-correct-string-widths
+		    'length))
+	(substring-fun (if gnus-use-correct-string-widths
 		       'gnus-correct-substring
-		     'substring)
-		  ,el 0 ,max))
+		     'substring)))
+    (if (symbolp el)
+	`(if (> (,length-fun ,el) ,max)
+	     ,(if (< max-width 0)
+		  `(,substring-fun ,el (- (,length-fun ,el) ,max))
+		`(,substring-fun ,el 0 ,max))
 	   ,el)
       `(let ((val (eval ,el)))
-	 (if (> (,(if gnus-use-correct-string-widths
-		      'gnus-correct-length
-		    'length) val) ,max)
+	 (if (> (,length-fun val) ,max)
 	     ,(if (< max-width 0)
-		  `(,(if gnus-use-correct-string-widths
-			 'gnus-correct-substring
-		       'substring)
-		    val (- (,(if gnus-use-correct-string-widths
-				 'gnus-correct-length
-			       'length) val) ,max))
-		`(,(if gnus-use-correct-string-widths
-		       'gnus-correct-substring
-		     'substring)
-		  val 0 ,max))
+		  `(,substring-fun val (- (,length-fun val) ,max))
+		`(,substring-fun val 0 ,max))
 	   val)))))
 
 (defun gnus-tilde-cut-form (el cut-width)
   "Return a form that cuts CUT-WIDTH off of EL."
-  (let ((cut (abs cut-width)))
-    (if (symbolp el)
-	`(if (> (,(if gnus-use-correct-string-widths
+  (let ((cut (abs cut-width))
+	(length-fun (if gnus-use-correct-string-widths
 		      'gnus-correct-length
-		    'length) ,el) ,cut)
-	     ,(if (< cut-width 0)
-		  `(,(if gnus-use-correct-string-widths
-			 'gnus-correct-substring
-		       'substring) ,el 0
-		       (- (,(if gnus-use-correct-string-widths
-				'gnus-correct-length
-			      'length) el) ,cut))
-		`(,(if gnus-use-correct-string-widths
+		    'length))
+	(substring-fun (if gnus-use-correct-string-widths
 		       'gnus-correct-substring
-		     'substring) ,el ,cut))
+		     'substring)))
+    (if (symbolp el)
+	`(if (> (,length-fun ,el) ,cut)
+	     ,(if (< cut-width 0)
+		  `(,substring-fun ,el 0 (- (,length-fun ,el) ,cut))
+		`(,substring-fun ,el ,cut))
 	   ,el)
       `(let ((val (eval ,el)))
-	 (if (> (,(if gnus-use-correct-string-widths
-		      'gnus-correct-length
-		    'length) val) ,cut)
+	 (if (> (,length-fun val) ,cut)
 	     ,(if (< cut-width 0)
-		  `(,(if gnus-use-correct-string-widths
-			 'gnus-correct-substring
-		       'substring) val 0
-		       (- (,(if gnus-use-correct-string-widths
-				'gnus-correct-length
-			      'length) val) ,cut))
-		`(,(if gnus-use-correct-string-widths
-		       'gnus-correct-substring
-		     'substring) val ,cut))
+		  `(,substring-fun val 0 (- (,length-fun val) ,cut))
+		`(,substring-fun val ,cut))
 	   val)))))
 
 (defun gnus-tilde-ignore-form (el ignore-value)

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2001-09-13  Martin Kretzschmar  <Martin.Kretzschmar@inf.tu-dresden.de>

	* gnus-spec.el (gnus-correct-substring): Still stopped one
	character before we wanted (never included last character).
	(gnus-tilde-max-form, gnus-tilde-cut-form) Made readable again,
	add missing "," (once per function)


        Martin