Re: comint read-only prompt

["Stefan Monnier" <monnier+gnu/emacs@rum.cs.yale.edu>]

> On Mon, Aug 19, 2002 at 08:57:59AM -0700, JD Smith wrote:
> > Another option I tried is adding, at the time of overlay move, a
> > read-only text property (and don't forget rear-nonsticky).  I reasoned
> > that this is perfectly acceptable given the new use of text properties
> > in CVS comint.  I didn't like the error message as much.
> 
> Given how often this sort of complaint turns up (that a read-only property is
> a good solution except for the error message), how about this idea: If a
> signalling an error due to a read-only property, if the property's value is a
> string, use that as the error message rather than the default.

I can only agree given that I've thought about the same thing a few
months back and even did some attempt at coding; see patch below.
The print_error_message needs to be updated as well, but I didn't
go that far.


	Stefan


Index: textprop.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/textprop.c,v
retrieving revision 1.132
diff -u -r1.132 textprop.c
--- textprop.c	16 Jul 2002 17:37:14 -0000	1.132
+++ textprop.c	20 Aug 2002 16:10:19 -0000
@@ -83,9 +83,10 @@
    to capture that error in GDB by putting a breakpoint on it.  */
 
 static void
-text_read_only ()
+text_read_only (propval)
+     Lisp_Object propval;
 {
-  Fsignal (Qtext_read_only, Qnil);
+  Fsignal (Qtext_read_only, STRINGP (propval) ? Fcons (propval, Qnil) : Qnil);
 }
 
 
@@ -2051,7 +2052,7 @@
 		      if (TMEM (Qread_only, tem)
 			  || (NILP (Fplist_get (i->plist, Qread_only))
 			      && TMEM (Qcategory, tem)))
-			text_read_only ();
+			text_read_only (after);
 		    }
 		}
 
@@ -2071,7 +2072,7 @@
 		      if (! TMEM (Qread_only, tem)
 			  && (! NILP (Fplist_get (prev->plist,Qread_only))
 			      || ! TMEM (Qcategory, tem)))
-			text_read_only ();
+			text_read_only (before);
 		    }
 		}
 	    }
@@ -2090,13 +2091,13 @@
 		  if (TMEM (Qread_only, tem)
 		      || (NILP (Fplist_get (i->plist, Qread_only))
 			  && TMEM (Qcategory, tem)))
-		    text_read_only ();
+		    text_read_only (after);
 
 		  tem = textget (prev->plist, Qrear_nonsticky);
 		  if (! TMEM (Qread_only, tem)
 		      && (! NILP (Fplist_get (prev->plist, Qread_only))
 			  || ! TMEM (Qcategory, tem)))
-		    text_read_only ();
+		    text_read_only (after);
 		}
 	    }
 	}
@@ -2118,7 +2119,7 @@
       do
 	{
 	  if (! INTERVAL_WRITABLE_P (i))
-	    text_read_only ();
+	    text_read_only (textget (i->plist, Qread_only));
 
 	  if (!inhibit_modification_hooks)
 	    {