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From: lra@rduxb.UUCP (Lonnie R. Abelbeck, AT&T Bell Labs)
Newsgroups: net.micro.mac
Subject: Re: Use of command keys
Message-ID: <503@rduxb.UUCP>
Date: Sun, 9-Jun-85 02:12:59 EDT
Article-I.D.: rduxb.503
Posted: Sun Jun  9 02:12:59 1985
Date-Received: Mon, 10-Jun-85 21:00:27 EDT
References: <190@tmq.UUCP> <26700017@inmet.UUCP> <653@wanginst.UUCP>
Organization: AT&T Bell Laboratories, Reading, PA
Lines: 34

> 
> Was this a MacTerminal mistake that everyone copied?  Or is there some
> reason?  Lonnie Abelbeck, do you know the answer?
> 

Well, I'm not one for copying MacTerminal mistakes, but there are a couple
good reasons for using the Command Key for the "control" key.

First, the Command and Option keys are treated differently by the Event
Manager.  The Command key is "detected" while another key is depressed,
therefore Command-A is treated as "A" with the Command key depressed.
The Option key treats the key as a totally new character defined in the
KeyMap Resource on startup.  Typically the Option key generates characters
with Hex values greater than 0x7F with no real order, so Option-A is
the foobar character and Option-A is not neccessarily one less than
Option-B.  Therefore by simply AND'ing the generated character with 0x1f
when the Command key is detected results in both Command-a and Command-A
yielding Control-A.

Second.... you say, just DEFINE Option-A to yield Control-A in the KeyMap
Resource.  You don't want to do this if you want to keep foreign compatibility.
By using the Command key approach, when the foreign Localizer program is
run to edit the Key resource, the new A'ish character is detected with the
Command key and a Control-A is generated.  If the terminal program messes
around with the Keymap you will no doubt screw-up the foreign mapping.
(this is the reason I have resisted using the Option Key as a Meta Key
in VersaTerm)

Third, the Command key is easier to hit than the Option Key.

I hope this helps....

Lonnie Abelbeck
ihnp4!rduxb!lra