keycap proposal

[Bob Stayton <bobs@sco.com>]

I'm following up on one of my action items from
the DocBook Technical Committee, this one
to develop a concrete proposal for semantic keycaps,
in response to RFE 697374 [1].

The RFE pointed out that while a keycap
element can contain text that indicates the marks
on the top of a key, there are some keys that
are special because they perform a function, such
as Ctrl, Shift, Alt, etc.  It would be better to capture
the semantic function of such special keys, so that they
can be rendered by a stylesheet in an appropriate manner
or language.  Examples: Ctrl-H,  C-h (Emacs), Strg-H (German).

The simplest solution is to add a 'function' attribute
with enumerated values to the keycap element.  The keycap
element content could then be empty, or could contain
a default text string.  The most common keys would be
enumerated, as shown below.  But it is not possible to
list all possible function keys for all keyboards.  So one
of the enumerated values would be 'other', which would
indicate that another CDATA attribute 'otherfunction'
should be used.  This is similar to the 'action' and
'otheraction' attributes of the keycombo element.

So the proposed new attributes for keycap are:

function     (alt
             |control
             |shift
	     |meta
	     |escape
	     |enter
	     |tab
	     |backspace
	     |command
	     |option
	     |space
	     |delete
	     |insert
	     |up
	     |down
	     |left
	     |right
	     |home
	     |end
	     |pageup
	     |pagedown
	     |other)        #IMPLIED

otherfunction  CDATA        #IMPLIED

Are there any comments on this proposal?


[1] https://sourceforge.net/tracker/index.php?func=detail&aid=697374&group_id=21935&atid=384107

Bob Stayton                                 400 Encinal Street
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