Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!apple!bionet!agate!ucbvax!SUMEX-AIM.STANFORD.EDU!lane
From: lane@SUMEX-AIM.STANFORD.EDU (Christopher Lane)
Newsgroups: comp.sys.xerox
Subject: Re: End to reverse-video PAGEFULLFNs
Message-ID: <622126715.A4816.KSL-1186-13.lane@SUMEX-AIM.Stanford.EDU>
Date: 6 Oct 88 16:12:43 GMT
References: <12436151294.19.KARP@SUMEX-AIM.Stanford.EDU>
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: info-1100@tut.cis.ohio-state.edu
Organization: The Internet
Lines: 44

Peter,

you might want to consider a formulation of the function something like:

(PAGEFULLFN
  (LAMBDA (WINDOW)             
          (if (NOT (READP T))
           then (RESETLST (RESETSAVE (CONTROL T))
                          (RESETSAVE (INVERTW WINDOW PAGEFULL.TEXTURE)
                                     `(INVERTW ,WINDOW ,PAGEFULL.TEXTURE))
                          (READC))))) 
  
This will restore the window both on the user typing a character and if an
error occurs, eg. the user types ^E (which leaves the window full of dots if
you use the function you provided).

Also, unless I'm missing something, it seems you want (CONTROL NIL) after your
READC, not (CONTROL T) again, as your function permanently leaves things in
the non-default state (the RESETSAVE version above fixes this problem).  You
might also want to remove ':'s in comments (on 'PKarp' and 'Actions') to make
the code easier to enter for post-Koto users (':' is the package marker).

Another problem with your PAGEFULLFN (and the rewrite above), at least under
Medley--haven't tried Koto, is that if you evaluate the following two forms
(in a small EXEC window) the window holding is not the same:

SYSFILES

(PROGN SYSFILES)

due to the READC & CONTROL interacting (or not) with the <RETURN>.  An
alternate approach which gets around this problem (works in Medley but might
need tuning for Koto) is:

(DEFINEQ (PAGEFULL.INVERTW (LAMBDA (WINDOW SHADE)
                              (INVERTW WINDOW (OR SHADE PAGEFULL.TEXTURE)))))

(CHANGENAME 'PAGEFULLFN 'INVERTW 'PAGEFULL.INVERTW)

which preserves the functionality of the original PAGEFULLFN but imposes a new
shade on it (note you can't use ADVISE here as INVERTW is both called twice,
once as part of a reset form, thus the second call would not be modified).

- Christopher