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From: lsr@apple.UUCP (Larry Rosenstein)
Newsgroups: net.micro.mac
Subject: Dead Keys
Message-ID: <94@apple.UUCP>
Date: Mon, 28-Jul-86 21:01:21 EDT
Article-I.D.: apple.94
Posted: Mon Jul 28 21:01:21 1986
Date-Received: Tue, 29-Jul-86 01:52:53 EDT
Organization: Advanced Development Group, Apple Computer
Lines: 42
Keywords: dead keys, MacTerminal, Red Ryder

{}

A long time ago there was a discussion of using the Option key as Control in
Red Ryder.  The problem is that certain option key combinations (eg.,
Option-e) are dead keys and don't generate a character until the next key is
typed.  

Contrary to the messages posted at the time, it is very easy to disable
dead keys in the keyboard driver (although I'm not sure that this has been
documented).  MacTerminal does it, in fact.

Basically, there are 2 resources (pieces of code, actually) that map raw
keycodes, generated by the keyboard, into ASCII characters.  One resource
handles the main keyboard and the other the external keypad.  It is
possible to completely replace these resources if you want to modify the
mapping in some unusual way.

Turning off dead keys, however, is very easy and already provided in the
system.  Low memory location $29E contains the address of the main mapping
function.  The resource begins with a 2-byte BRA instruction, followed by a
1-byte flag.

If the flag is $FF then dead keys are on, if it is $00, then dead keys are
off (ie., typing option-E will give you an accent character immediately).
It's as easy as that.  Programs that turn off dead keys should make sure to
re-enable them when they terminate.

It would be trivial to write a desk accessory that allows you to
enable/disable dead keys at any time.  Then it might be more convenient to
use the Option key in Red Ryder.

I hope this helps current and future terminal emulators.

-- 
Larry Rosenstein

Object Specialist
Apple Computer

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