+@defun add-face-text-property start end face &optional appendp object
+This function acts on the text between @var{start} and @var{end},
+adding the face @var{face} to the @code{face} text property.
+@var{face} should be a valid value for the @code{face} property
+(@pxref{Special Properties}), such as a face name or an anonymous face
+(@pxref{Faces}).
+
+If any text in the region already has a non-@code{nil} @code{face} property,
+those face(s) are retained. This function sets the @code{face}
+property to a list of faces, with @var{face} as the first element (by
+default) and the pre-existing faces as the remaining elements. If the
+optional argument @var{append} is non-@code{nil}, @var{face} is
+appended to the end of the list instead. Note that in a face list,
+the first occurring value for each attribute takes precedence.
+
+For example, the following code would assign a italicized green face
+to the text between @var{start} and @var{end}:
+
+@example
+(add-face-text-property @var{start} @var{end} 'italic)
+(add-face-text-property @var{start} @var{end} '(:foreground "red"))
+(add-face-text-property @var{start} @var{end} '(:foreground "green"))
+@end example
+
+The optional argument @var{object}, if non-@code{nil}, specifies a
+buffer or string to act on, rather than the current buffer. If
+@var{object} is a string, then @var{start} and @var{end} are
+zero-based indices into the string.
+@end defun
+
+ The easiest way to make a string with text properties is with
+@code{propertize}: