meta key

[Andy Witkin]

		HOW TO INSTALL A META KEY IN IRIX 3.1

1.  If you use gnu emacs, put 
	(setq meta-flag 1)
    into your .emacs file.  You need do nothing special 
    for unipress emacs.

2.  Copy /usr/NeWS/lib/NeWS/UI.ps to ~/NeWS/UI.ps

3.  Edit your private copy of UI.ps:

Find this portion: 

    /deliver_keyboard_to_focus {				% event => -
	dup dup begin						% ev ev
	    sgi_translatekey					% ev (string)
	    /ClientData exch def				% ev

and add code before and after as follows:


/MetaDown false def			% true when either alt key is down

{
    createevent dup begin 		% gobble alt key
	    /Name [28560 28559] def
	    /Priority 4 def
	    /Exclusivity true def
	end
    expressinterest
    {
	awaitevent
	dup /Action get /DownTransition eq
		{/MetaDown true store}     % downtrans -> set  flag
		{/MetaDown false store}	   % uptrans -> clear flag
	ifelse
    } loop
} fork


    /deliver_keyboard_to_focus {		% EXISTING CODE
	dup dup begin				% EXISTING CODE
	    sgi_translatekey			% EXISTING CODE
	    dup dup type /stringtype eq		% if there's a string
	    exch length 0 ne and		% of nonzero length
	    MetaDown and			% and meta is down
	    Action /DownTransition eq and	% and ev is a keypress
	    {dup dup 0 get 128 or		% then ior 128 into
	     0 exch put				% the 1st char in the string
	    } if
	    /ClientData exch def		% EXISTING CODE


4. Log out and log back in.  Alt is now a meta key.  (If you get in
trouble, log in as someone else, rename ~/NeWS/UI.ps to something
else, and figure out what you did wrong.)


(This hack does two things: We fork a process that gobbles alt key
presses and maintains our /MetaDown flag.  And we add some code to
deliver_keyboard_to_focus, a routine that runs whenever a key is
pressed.  

deliver_keyboard_to_focus calls sgi_translatekey, sgi's routine that
takes an event and stuffs a translation string on the stack.  When the
meta key is down, our added code checks to see if sgi_translatekey
left a non-empty string on top of the stack, and if so, sets the high
bit in the string's first character.  The hacked string is then salted
away in the /ClientData field of the event for god-knows-who to look
at later.)

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