Re: default-truncate-lines

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> -(defcustom gnus-article-truncate-lines default-truncate-lines
>> +(defcustom gnus-article-truncate-lines (default-value 'truncate-lines)
> I don't care about this change, but out of curiosity: (why) does it
> make a difference?

Every time I see one of those default-FOO variable used I get flashes of
the following code:

	  /* If this variable is a default for something stored
	     in the buffer itself, such as default-fill-column,
	     find the buffers that don't have local values for it
	     and update them.  */
	  if (XOBJFWD (valcontents)->objvar > (Lisp_Object *) &buffer_defaults
	      && XOBJFWD (valcontents)->objvar < (Lisp_Object *) (&buffer_defaults + 1))
	    {
	      int offset = ((char *) XOBJFWD (valcontents)->objvar
			    - (char *) &buffer_defaults);
	      int idx = PER_BUFFER_IDX (offset);

	      Lisp_Object tail;

	      if (idx <= 0)
		break;

	      for (tail = Vbuffer_alist; CONSP (tail); tail = XCDR (tail))
		{
		  Lisp_Object buf;
		  struct buffer *b;

		  buf = Fcdr (XCAR (tail));
		  if (!BUFFERP (buf)) continue;
		  b = XBUFFER (buf);

		  if (! PER_BUFFER_VALUE_P (b, idx))
		    PER_BUFFER_VALUE (b, offset) = newval;
		}
	    }

and every time I get to replace it with a use of `default-value', I feel
like maybe this madness will disappear some day.


        Stefan