Doc improvements for face remapping.

* face-remap.el (face-remap-add-relative, face-remap-set-base)
(buffer-face-set, buffer-face-toggle, buffer-face-mode-invoke):
Doc fixes.

* doc/lispref/display.texi (Face Remapping): Minor clarification.

* doc/lispref/text.texi (Special Properties): Clarify the meaning of a
list of faces in the `face' property.

Fixes: debbugs:11225

5 files changed, 69 insertions, 44 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index 3c9f26d6a24..cbe081ca6b4 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,3 +1,10 @@
+2012-06-09  Chong Yidong  <cyd@gnu.org>
+
+	* text.texi (Special Properties): Clarify the meaning of a list of
+	faces in the `face' property.
+
+	* display.texi (Face Remapping): Minor clarification.
+
 2012-06-08  Chong Yidong  <cyd@gnu.org>
 
 	* display.texi (Face Attributes): Font family does not accept
diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 53e800bfbf0..3725b6fd820 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -2511,39 +2511,34 @@ Scale,,, emacs, The GNU Emacs Manual}).
 The value of this variable is an alist whose elements have the form
 @code{(@var{face} . @var{remapping})}.  This causes Emacs to display
 any text having the face @var{face} with @var{remapping}, rather than
-the ordinary definition of @var{face}.  @var{remapping} may be any
-face specification suitable for a @code{face} text property: either a
-face name, or a property list of attribute/value pairs, or a list in
-which each element is either a face name or a property list
-(@pxref{Special Properties}).
+the ordinary definition of @var{face}.
+
+@var{remapping} may be any face specification suitable for a
+@code{face} text property: either a face (i.e.@: a face name or a
+property list of attribute/value pairs), or a list of faces.  For
+details, see the description of the @code{face} text property in
+@ref{Special Properties}.  @var{remapping} serves as the complete
+specification for the remapped face---it replaces the normal
+definition of @var{face}, instead of modifying it.
 
 If @code{face-remapping-alist} is buffer-local, its local value takes
 effect only within that buffer.
 
-Two points bear emphasizing:
-
-@enumerate
-@item
-@var{remapping} serves as the complete specification for the remapped
-face---it replaces the normal definition of @var{face}, instead of
-modifying it.
-
-@item
-If @var{remapping} references the same face name @var{face}, either
-directly or via the @code{:inherit} attribute of some other face in
-@var{remapping}, that reference uses the normal definition of
-@var{face}.  In other words, the remapping cannot be recursive.
+Note: face remapping is non-recursive.  If @var{remapping} references
+the same face name @var{face}, either directly or via the
+@code{:inherit} attribute of some other face in @var{remapping}, that
+reference uses the normal definition of @var{face}.  For instance, if
+the @code{mode-line} face is remapped using this entry in
+@code{face-remapping-alist}:
 
-For instance, if the @code{mode-line} face is remapped using this
-entry in @code{face-remapping-alist}:
 @example
 (mode-line italic mode-line)
 @end example
+
 @noindent
 then the new definition of the @code{mode-line} face inherits from the
 @code{italic} face, and the @emph{normal} (non-remapped) definition of
 @code{mode-line} face.
-@end enumerate
 @end defvar
 
   The following functions implement a higher-level interface to
diff --git a/doc/lispref/text.texi b/doc/lispref/text.texi
index e2bdc707c5b..63a6d2cbab3 100644
--- a/doc/lispref/text.texi
+++ b/doc/lispref/text.texi
@@ -3004,7 +3004,11 @@ time you want to specify a particular attribute for certain text.
 @xref{Face Attributes}.
 
 @item
-A list, where each element uses one of the two forms listed above.
+A list of faces.  This specifies a face which is an aggregate of the
+attributes of each of the listed faces.  Faces occurring earlier in
+the list have higher priority.  Each list element must have one of the
+two above forms (i.e.@: either a face name or a property list of face
+attributes).
 @end itemize
 
 Font Lock mode (@pxref{Font Lock Mode}) works in most buffers by
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 72a9cb352a5..d75a1d52799 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2012-06-09  Chong Yidong  <cyd@gnu.org>
+
+	* face-remap.el (face-remap-add-relative, face-remap-set-base)
+	(buffer-face-set, buffer-face-toggle, buffer-face-mode-invoke):
+	Doc fixes (Bug#11225).
+
 2012-06-09  Stefan Monnier  <monnier@iro.umontreal.ca>
 
 	* emacs-lisp/macroexp.el (macroexp--expand-all): Only autoload
diff --git a/lisp/face-remap.el b/lisp/face-remap.el
index 46dad0fca3a..be2207a993f 100644
--- a/lisp/face-remap.el
+++ b/lisp/face-remap.el
@@ -109,14 +109,19 @@ The list structure of ENTRY may be destructively modified."
 Return a cookie which can be used to delete this remapping with
 `face-remap-remove-relative'.
 
-The remaining arguments, SPECS, should be either a list of face
-names, or a property list of face attribute/value pairs.  The
-remapping specified by SPECS takes effect alongside the
-remappings from other calls to `face-remap-add-relative', as well
-as the normal definition of FACE (at lowest priority).  This
-function tries to sort multiple remappings for the same face, so
-that remappings specifying relative face attributes are applied
-after remappings specifying absolute face attributes.
+The remaining arguments, SPECS, should form a list of faces.
+Each list element should be either a face name or a property list
+of face attribute/value pairs.  If more than one face is listed,
+that specifies an aggregate face, in the same way as in a `face'
+text property, except for possible priority changes noted below.
+
+The face remapping specified by SPECS takes effect alongside the
+remappings from other calls to `face-remap-add-relative' for the
+same FACE, as well as the normal definition of FACE (at lowest
+priority).  This function tries to sort multiple remappings for
+the same face, so that remappings specifying relative face
+attributes are applied after remappings specifying absolute face
+attributes.
 
 The base (lowest priority) remapping may be set to something
 other than the normal definition of FACE via `face-remap-set-base'."
@@ -165,9 +170,11 @@ to apply on top of the normal definition of FACE."
 (defun face-remap-set-base (face &rest specs)
   "Set the base remapping of FACE in the current buffer to SPECS.
 This causes the remappings specified by `face-remap-add-relative'
-to apply on top of the face specification given by SPECS.  SPECS
-should be either a list of face names, or a property list of face
-attribute/value pairs.
+to apply on top of the face specification given by SPECS.
+
+The remaining arguments, SPECS, should form a list of faces.
+Each list element should be either a face name or a property list
+of face attribute/value pairs, like in a `face' text property.
 
 If SPECS is empty, call `face-remap-reset-base' to use the normal
 definition of FACE as the base remapping; note that this is
@@ -361,12 +368,14 @@ variable `buffer-face-mode-face' is used to display the buffer text."
 ;;;###autoload
 (defun buffer-face-set (&rest specs)
   "Enable `buffer-face-mode', using face specs SPECS.
-SPECS can be any value suitable for the `face' text property,
-including a face name, a list of face names, or a face-attribute
-If SPECS is nil, then `buffer-face-mode' is disabled.
-
-This function will make the variable `buffer-face-mode-face'
-buffer local, and set it to FACE."
+Each argument in SPECS should be a face, i.e. either a face name
+or a property list of face attributes and values.  If more than
+one face is listed, that specifies an aggregate face, like in a
+`face' text property.  If SPECS is nil or omitted, disable
+`buffer-face-mode'.
+
+This function makes the variable `buffer-face-mode-face' buffer
+local, and sets it to FACE."
   (interactive (list (read-face-name "Set buffer face")))
   (while (and (consp specs) (null (cdr specs)))
     (setq specs (car specs)))
@@ -378,8 +387,10 @@ buffer local, and set it to FACE."
 ;;;###autoload
 (defun buffer-face-toggle (&rest specs)
   "Toggle `buffer-face-mode', using face specs SPECS.
-SPECS can be any value suitable for the `face' text property,
-including a face name, a list of face names, or a face-attribute
+Each argument in SPECS should be a face, i.e. either a face name
+or a property list of face attributes and values.  If more than
+one face is listed, that specifies an aggregate face, like in a
+`face' text property.
 
 If `buffer-face-mode' is already enabled, and is currently using
 the face specs SPECS, then it is disabled; if buffer-face-mode is
@@ -402,10 +413,12 @@ buffer local, and set it to SPECS."
 ARG controls whether the mode is enabled or disabled, and is
 interpreted in the usual manner for minor-mode commands.
 
-SPECS can be any value suitable for the `face' text property,
-including a face name, a list of face names, or a face-attribute
+SPECS can be any value suitable for a `face' text property,
+including a face name, a plist of face attributes and values, or
+a list of faces.
 
-If INTERACTIVE is non-nil, a message will be displayed describing the result.
+If INTERACTIVE is non-nil, display a message describing the
+result.
 
 This is a wrapper function which calls `buffer-face-set' or
 `buffer-face-toggle' (depending on ARG), and prints a status