Implement new function `add-face-text-property'

* doc/lispref/text.texi (Changing Properties): Document `add-face-text-property'.

* src/textprop.c (property_set_type): New enum.
(add_properties): Allow appending/prepending text properties.
(add_text_properties_1): Factored out of Fadd_text_properties.
(Fadd_text_properties): Moved all the code into
add_text_properties_1.
(Fadd_face_text_property): New function that calls
add_text_properties_1.

1 files changed, 84 insertions, 17 deletions

diff --git a/src/textprop.c b/src/textprop.c
index 03b8de120cd..e5d4fe06c60 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -60,6 +60,13 @@ Lisp_Object Qinvisible, Qintangible, Qmouse_face;
 static Lisp_Object Qread_only;
 Lisp_Object Qminibuffer_prompt;
 
+enum property_set_type
+{
+  TEXT_PROPERTY_REPLACE,
+  TEXT_PROPERTY_PREPEND,
+  TEXT_PROPERTY_APPEND
+};
+
 /* Sticky properties.  */
 Lisp_Object Qfront_sticky, Qrear_nonsticky;
 
@@ -370,7 +377,8 @@ set_properties (Lisp_Object properties, INTERVAL interval, Lisp_Object object)
    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,
+                enum property_set_type set_type)
 {
   Lisp_Object tail1, tail2, sym1, val1;
   bool changed = 0;
@@ -416,7 +424,30 @@ add_properties (Lisp_Object plist, INTERVAL i, Lisp_Object object)
               }
 
             /* I's property has a different value -- change it */
-            Fsetcar (this_cdr, val1);
+            if (set_type == TEXT_PROPERTY_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))))))
+                /* The previous value is a list, so prepend (or
+                   append) the new value to this list. */
+                if (set_type == TEXT_PROPERTY_PREPEND)
+                  Fsetcar (this_cdr, Fcons (val1, Fcar (this_cdr)));
+                else
+                  nconc2 (Fcar (this_cdr), Fcons (val1, Qnil));
+              else {
+                /* The previous value is a single value, so make it
+                   into a list. */
+                if (set_type == TEXT_PROPERTY_PREPEND)
+                  Fsetcar (this_cdr,
+                           Fcons (val1, Fcons (Fcar (this_cdr), Qnil)));
+                else
+                  Fsetcar (this_cdr,
+                           Fcons (Fcar (this_cdr), Fcons (val1, Qnil)));
+              }
+            }
             changed = 1;
             break;
           }
@@ -1124,19 +1155,12 @@ back past position LIMIT; return LIMIT if nothing is found until LIMIT.  */)
     return make_number (previous->position + LENGTH (previous));
 }
 
-/* Callers note, this can GC when OBJECT is a buffer (or nil).  */
+/* Used by add-text-properties and add-face-text-property. */
 
-DEFUN ("add-text-properties", Fadd_text_properties,
-       Sadd_text_properties, 3, 4, 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.
-Return t if any property value actually changed, nil otherwise.  */)
-  (Lisp_Object start, Lisp_Object end, Lisp_Object properties, Lisp_Object object)
-{
+static Lisp_Object
+add_text_properties_1 (Lisp_Object start, Lisp_Object end,
+                       Lisp_Object properties, Lisp_Object object,
+                       enum property_set_type set_type) {
   INTERVAL i, unchanged;
   ptrdiff_t s, len;
   bool modified = 0;
@@ -1230,7 +1254,7 @@ Return t if any property value actually changed, nil otherwise.  */)
 
           if (LENGTH (i) == len)
             {
-              add_properties (properties, i, object);
+              add_properties (properties, i, object, set_type);
               if (BUFFERP (object))
                 signal_after_change (XINT (start), XINT (end) - XINT (start),
                                      XINT (end) - XINT (start));
@@ -1241,7 +1265,7 @@ Return t if any property value actually changed, nil otherwise.  */)
           unchanged = i;
           i = split_interval_left (unchanged, len);
           copy_properties (unchanged, i);
-          add_properties (properties, i, object);
+          add_properties (properties, i, object, set_type);
           if (BUFFERP (object))
             signal_after_change (XINT (start), XINT (end) - XINT (start),
                                  XINT (end) - XINT (start));
@@ -1249,13 +1273,31 @@ Return t if any property value actually changed, nil otherwise.  */)
         }
 
       len -= LENGTH (i);
-      modified |= add_properties (properties, i, object);
+      modified |= add_properties (properties, i, object, set_type);
       i = next_interval (i);
     }
 }
 
 /* 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,
+       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.
+Return t if any property value actually changed, nil otherwise.  */)
+  (Lisp_Object start, Lisp_Object end, Lisp_Object properties,
+   Lisp_Object object)
+{
+  return add_text_properties_1 (start, end, properties, object,
+                                TEXT_PROPERTY_REPLACE);
+}
+
+/* Callers note, this can GC when OBJECT is a buffer (or nil).  */
+
 DEFUN ("put-text-property", Fput_text_property,
        Sput_text_property, 4, 5, 0,
        doc: /* Set one property of the text from START to END.
@@ -1287,6 +1329,29 @@ the designated part of OBJECT.  */)
 }
 
 
+DEFUN ("add-face-text-property", Fadd_face_text_property,
+       Sadd_face_text_property, 3, 5, 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 APPENDP is non-nil, append to the end
+of the face property list instead.
+If the optional fifth 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 appendp, Lisp_Object object)
+{
+  add_text_properties_1 (start, end,
+                         Fcons (Qface, Fcons (face, Qnil)),
+                         object,
+                         NILP (appendp)? TEXT_PROPERTY_PREPEND:
+                         TEXT_PROPERTY_APPEND);
+  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.
@@ -2292,6 +2357,7 @@ inherits it if NONSTICKINESS is nil.  The `front-sticky' and
   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 +2392,7 @@ inherits it if NONSTICKINESS is nil.  The `front-sticky' and
   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);