Re: `add-face'

[Lars Magne Ingebrigtsen]

Stefan Monnier <address@hidden> writes:

>> This is too vague.  What does "add the text properties" mean?  If the
>> current value of a property is nil, and the argument to
>> add-text-properties specifies a value `foo', does the new value become
>> `foo' or `(foo)'?  If the current value is `1', does the new value
>> become `(foo 1)' or something else?
>> And, specifically for face properties, what if the current value is a
>> list specifying an anonymous face, like `(:foreground "black")'?
>
> Yup, it's much better to provide a dedicated add-face-text-property.

I totally dropped the ball on this one, but was reminded when I
re-discovered that most of the time spent in shr.el when rendering
Wikipedia pages is doing manual face/overlay stuff.

I looked for the code for quite a while until I remembered that it was
on a laptop.  I've now re-spun the code, and there is a dedicated
`add-face-text-property' function and anonymous face properties are
handled correctly.

But I'd still like to have the extended `add-text-properties' function,
because then shr.el can say

(add-text-properties start end
 '(face underline shr-data :foo widget-stuff :blah)
 nil t)

instead of splitting stuff up.  For some reason or other, that speeds
stuff up by 20%...

But if the `add-text-properties' extension is a no-no, I can re-spin the
patch to not include that, but it'll entail a bit more code-change,
since the body of `add-text-properties' will have to be split up for
reuse.

Here's the patch:

=== modified file 'src/editfns.c'
--- src/editfns.c       2013-05-18 05:32:17 +0000
+++ src/editfns.c       2013-06-17 07:15:47 +0000
@@ -3563,7 +3563,7 @@
 
   Fadd_text_properties (make_number (0),
                        make_number (SCHARS (string)),
-                       properties, string);
+                       properties, string, Qnil);
   RETURN_UNGCPRO (string);
 }
 

=== modified file 'src/minibuf.c'
--- src/minibuf.c       2013-05-04 19:27:41 +0000
+++ src/minibuf.c       2013-06-17 07:15:47 +0000
@@ -649,7 +649,7 @@
        Fput_text_property (make_number (BEG), make_number (PT),
                            Qfield, Qt, Qnil);
        Fadd_text_properties (make_number (BEG), make_number (PT),
-                             Vminibuffer_prompt_properties, Qnil);
+                             Vminibuffer_prompt_properties, Qnil, Qnil);
       }
     unbind_to (count1, Qnil);
   }

=== modified file 'src/textprop.c'
--- src/textprop.c      2013-06-17 06:03:19 +0000
+++ src/textprop.c      2013-06-17 07:43:38 +0000
@@ -370,7 +370,8 @@
    are actually added to I's plist) */
 
 static bool
-add_properties (Lisp_Object plist, INTERVAL i, Lisp_Object object)
+add_properties (Lisp_Object plist, INTERVAL i, Lisp_Object object,
+               bool replace)
 {
   Lisp_Object tail1, tail2, sym1, val1;
   bool changed = 0;
@@ -416,7 +417,17 @@
              }
 
            /* I's property has a different value -- change it */
-           Fsetcar (this_cdr, val1);
+           if (replace)
+             Fsetcar (this_cdr, val1);
+           else {
+             if (CONSP (Fcar (this_cdr)) &&
+                 /* Special-case anonymous face properties. */
+                 (! EQ (sym1, Qface) ||
+                  NILP (Fkeywordp (Fcar (Fcar (this_cdr))))))
+               Fsetcar (this_cdr, Fcons (val1, Fcar (this_cdr)));
+             else
+               Fsetcar (this_cdr, Fcons (val1, Fcons (Fcar (this_cdr), Qnil)));
+           }
            changed = 1;
            break;
          }
@@ -1127,20 +1138,24 @@
 /* Callers note, this can GC when OBJECT is a buffer (or nil).  */
 
 DEFUN ("add-text-properties", Fadd_text_properties,
-       Sadd_text_properties, 3, 4, 0,
+       Sadd_text_properties, 3, 5, 0,
        doc: /* Add properties to the text from START to END.
 The third argument PROPERTIES is a property list
 specifying the property values to add.  If the optional fourth argument
 OBJECT is a buffer (or nil, which means the current buffer),
 START and END are buffer positions (integers or markers).
 If OBJECT is a string, START and END are 0-based indices into it.
+If NOREPLACE, add the text properties instead of replacing any
+existing ones.  This is mainly useful for faces.
 Return t if any property value actually changed, nil otherwise.  */)
-  (Lisp_Object start, Lisp_Object end, Lisp_Object properties, Lisp_Object 
object)
+  (Lisp_Object start, Lisp_Object end, Lisp_Object properties,
+   Lisp_Object object, Lisp_Object noreplace)
 {
   INTERVAL i, unchanged;
   ptrdiff_t s, len;
   bool modified = 0;
   struct gcpro gcpro1;
+  bool replace = NILP (noreplace);
   bool first_time = 1;
 
   properties = validate_plist (properties);
@@ -1230,7 +1245,7 @@
 
          if (LENGTH (i) == len)
            {
-             add_properties (properties, i, object);
+             add_properties (properties, i, object, replace);
              if (BUFFERP (object))
                signal_after_change (XINT (start), XINT (end) - XINT (start),
                                     XINT (end) - XINT (start));
@@ -1241,7 +1256,7 @@
          unchanged = i;
          i = split_interval_left (unchanged, len);
          copy_properties (unchanged, i);
-         add_properties (properties, i, object);
+         add_properties (properties, i, object, replace);
          if (BUFFERP (object))
            signal_after_change (XINT (start), XINT (end) - XINT (start),
                                 XINT (end) - XINT (start));
@@ -1249,7 +1264,7 @@
        }
 
       len -= LENGTH (i);
-      modified |= add_properties (properties, i, object);
+      modified |= add_properties (properties, i, object, replace);
       i = next_interval (i);
     }
 }
@@ -1268,7 +1283,7 @@
 {
   Fadd_text_properties (start, end,
                        Fcons (property, Fcons (value, Qnil)),
-                       object);
+                       object, Qnil);
   return Qnil;
 }
 
@@ -1287,6 +1302,23 @@
 }
 
 
+DEFUN ("add-face-text-property", Fadd_face_text_property,
+       Sadd_face_text_property, 3, 4, 0,
+       doc: /* Add the face property to the text from START to END.
+The third argument FACE specifies the face to add.
+If any text in the region already has any face properties, this new
+face property will be added to the front of the face property list.
+If the optional fourth argument OBJECT is a buffer (or nil, which means
+the current buffer), START and END are buffer positions (integers or
+markers).  If OBJECT is a string, START and END are 0-based indices into it.  
*/)
+  (Lisp_Object start, Lisp_Object end, Lisp_Object face, Lisp_Object object)
+{
+  Fadd_text_properties (start, end,
+                       Fcons (Qface, Fcons (face, Qnil)),
+                       object, Qt);
+  return Qnil;
+}
+ 
 /* Replace properties of text from START to END with new list of
    properties PROPERTIES.  OBJECT is the buffer or string containing
    the text.  OBJECT nil means use the current buffer.
@@ -1893,7 +1925,7 @@
     {
       res = Fcar (stuff);
       res = Fadd_text_properties (Fcar (res), Fcar (Fcdr (res)),
-                                 Fcar (Fcdr (Fcdr (res))), dest);
+                                 Fcar (Fcdr (Fcdr (res))), dest, Qnil);
       if (! NILP (res))
        modified = 1;
       stuff = Fcdr (stuff);
@@ -1984,7 +2016,7 @@
       end = make_number (XINT (XCAR (XCDR (item))) + XINT (delta));
       plist = XCAR (XCDR (XCDR (item)));
 
-      Fadd_text_properties (start, end, plist, object);
+      Fadd_text_properties (start, end, plist, object, Qnil);
     }
 
   UNGCPRO;
@@ -2292,6 +2324,7 @@
   DEFSYM (Qforeground, "foreground");
   DEFSYM (Qbackground, "background");
   DEFSYM (Qfont, "font");
+  DEFSYM (Qface, "face");
   DEFSYM (Qstipple, "stipple");
   DEFSYM (Qunderline, "underline");
   DEFSYM (Qread_only, "read-only");
@@ -2326,6 +2359,7 @@
   defsubr (&Sadd_text_properties);
   defsubr (&Sput_text_property);
   defsubr (&Sset_text_properties);
+  defsubr (&Sadd_face_text_property);
   defsubr (&Sremove_text_properties);
   defsubr (&Sremove_list_of_text_properties);
   defsubr (&Stext_property_any);

=== modified file 'src/xdisp.c'
--- src/xdisp.c 2013-06-15 09:34:20 +0000
+++ src/xdisp.c 2013-06-17 07:15:47 +0000
@@ -11692,7 +11692,7 @@
       else
        end = i + 1;
       Fadd_text_properties (make_number (i), make_number (end),
-                           props, f->desired_tool_bar_string);
+                           props, f->desired_tool_bar_string, Qnil);
 #undef PROP
     }
 
@@ -20886,7 +20886,7 @@
          props = Fplist_put (props, Qface, face);
        }
       Fadd_text_properties (make_number (0), make_number (len),
-                           props, lisp_string);
+                           props, lisp_string, Qnil);
     }
   else
     {
@@ -20913,7 +20913,7 @@
        }
       if (!NILP (props))
        Fadd_text_properties (make_number (0), make_number (len),
-                             props, lisp_string);
+                             props, lisp_string, Qnil);
     }
 
   if (len > 0)
@@ -20928,7 +20928,7 @@
       lisp_string = Fmake_string (make_number (field_width), make_number (' 
'));
       if (!NILP (props))
        Fadd_text_properties (make_number (0), make_number (field_width),
-                             props, lisp_string);
+                             props, lisp_string, Qnil);
       mode_line_string_list = Fcons (lisp_string, mode_line_string_list);
       n += field_width;
     }

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/