Re: USR( ) commands?

[Don Bruder <dakidd@sonic.net>]

In article <1112927445.336713.310040@o13g2000cwo.googlegroups.com>,
 "mspangler" <mspangler@gemsi.com> wrote:

> There are stacks of ampersand routines available, and mounds of
> external commands for ProDos, and even a few for DOS 3.3, and I've even
> seen a couple of control-Y commands for the monitor add on command. But
> I haven't seen diddly for the USR( ) command. Did anyone bother with
> it, or was it just too much hassle dealing with the FAC (Floating point
> ACcumulator)?
> 

It was a pretty limited-use item, or so my opinion has always been. The 
ampersand vector was more flexible, and saw much heavier use because of 
that fact. Among other limiting factors, USR() was/is a one-input, one 
output function. Wiring up the ampersand vector let you literally "go 
wild" in pretty much any way you wanted to - Pass it one input value and 
12 output pointers if you want. Or pass 10 inputs and get back one 
output. Or whatever you care to dream up, and can write the code to 
handle. :) 

USR() was strictly "one in, one out" unless you did "naughty things" to 
get at stuff you really weren't supposed to be able to get at according 
to "the rules". Ampersand let you get at the same stuff, but without 
needing to "go behind Applesoft's back" quite as blatantly to do it.

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