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From: pepke@loligo (Eric Pepke)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Serious programming question
Message-ID: <299@fsu.scri.fsu.edu>
Date: 23 Oct 89 15:21:20 GMT
References: <89295.142753CXT105@PSUVM.BITNET> <4002@helios.ee.lbl.gov> <8785@hoptoad.uucp>
Sender: news@fsu.scri.fsu.edu
Reply-To: pepke@loligo.UUCP (Eric Pepke)
Organization: Supercomputer Computations Research Institute
Lines: 26

It just so happens that I am curently working on a text editor for programming
right now.  I am using a single buffer with a single gap using long integers
to remember the offsets to the gap, which I think is similar to the way Capps 
used to do it.  (If Capps were still a supported product, I would probably be
using it.)

A reasonably large gap is kept at the current insertion point.  Normal 
character insertions just go into the gap and make the gap one character 
smaller.  Deletions of single characters just increase the size of the gap by
one.  The only times that text has to be moved are when a new gap is allocated
or the old gap is removed.  The idle routine tries to do this at unobtrusive
times.

Scroll bar handling is done as an integral part of the text editor.  I strongly
recommend that you do this rather than follow TextEdit's method.  Scroll bar
handling for long integers is very easy to do cleanly if you have enough 
information available.  If you try to tack it on outside of the editor a la
TextEdit, it is very difficult to do cleanly.

Eric Pepke                                     INTERNET: pepke@gw.scri.fsu.edu
Supercomputer Computations Research Institute  MFENET:   pepke@fsu
Florida State University                       SPAN:     scri::pepke
Tallahassee, FL 32306-4052                     BITNET:   pepke@fsu

Disclaimer: My employers seldom even LISTEN to my opinions.
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