(Window System Selections): Mention scrap support for Mac.

Default value of x-select-enable-clipboard is t on Mac.

diff --git a/lispref/frames.texi b/lispref/frames.texi
index 09887d000ddac52c33c4a1d741dc66a74bdda308..09b0df1615c9fb85a6c2488782dc31e143f994a7 100644 (file)
--- a/lispref/frames.texi
+++ b/lispref/frames.texi
@@ -1694,12 +1694,33 @@ and @code{x-set-selection} on MS-Windows support the text data type
 only; if the clipboard holds other types of data, Emacs treats the
 clipboard as empty.
 
+@cindex scrap support (for Mac OS)
+On Mac OS, selection-like data transfer between applications is
+performed through a mechanism called @dfn{scraps}.  The clipboard is a
+particular scrap named @code{com.apple.scrap.clipboard}.  Types of scrap
+data are called @dfn{scrap flavor types}, which are identified by
+four-char codes such as @code{TEXT}.  Emacs associates a selection with
+a scrap, and a selection type with a scrap flavor type via
+@code{mac-scrap-name} and @code{mac-ostype} properties, respectively.
+
+@example
+(get 'CLIPBOARD 'mac-scrap-name)
+     @result{} "com.apple.scrap.clipboard"
+(get 'com.apple.traditional-mac-plain-text 'mac-ostype)
+     @result{} "TEXT"
+@end example
+
+Conventionally, selection types for scrap flavor types on Mac OS have
+the form of @acronym{UTI, Uniform Type Identifier} such as
+@code{com.apple.traditional-mac-plain-text},
+@code{public.utf16-plain-text}, and @code{public.file-url}.
+
 @defopt x-select-enable-clipboard
 If this is non-@code{nil}, the Emacs yank functions consult the
 clipboard before the primary selection, and the kill functions store in
 the clipboard as well as the primary selection.  Otherwise they do not
 access the clipboard at all.  The default is @code{nil} on most systems,
-but @code{t} on MS-Windows.
+but @code{t} on MS-Windows and Mac.
 @end defopt
 
 @node Drag and Drop