Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!apple!vsi1!ubvax!ardent!rap
From: rap@ardent.UUCP (Rob Peck)
Newsgroups: comp.sys.amiga
Subject: Re: more 1.4 wishes
Summary: some of objections already addressed
Message-ID: <4128@ardent.UUCP>
Date: 6 Mar 89 19:33:43 GMT
References: <4Y3LOgy00WB7NFUmZh@andrew.cmu.edu> <61@snll-arpagw.UUCP>
Organization: Dana Computer, Inc., Sunnyvale, CA
Lines: 73

In article <61@snll-arpagw.UUCP>, paolucci@snll-arpagw.UUCP (Sam Paolucci) writes:
> I would like to see AmigaDOS grow up into a full blown command
> language which supports looping, testing (and I don't just mean WARN
> and all that crap), branching (like a goto (god forbid) so you can go
> back up in a script), variables, etc.
> 
> write a program.  All you have to do is look at the ASK command.  You
> can only use it for YES/NO questions, and even then you cannot even
> just test for YES/NO, you have to test for error condition flags.  Can

I believe that some of Sam's objections have already been addressed in
1.3 (I just finished a very thorough examination of the released docs
for an update to the Amiga Companion and found a lot to smile about).

Regarding looping, take a look at the SKIP <label> BACK 
which does indeed let you form a loop.  And the ENDSKIP command,
when used, forms what might be called the "default:" part of a case
statement wherein the execute-script-function does not fall off the
end just because it never found the label you asked it to skip to.

Related to the above, and handy because of it is the ability to
answer ANY question, not just YES/NO ... from an example by Andy
Finkel, and paraphrased:

	LAB BEGIN
	ECHO "TELL ME WHAT TO DO NEXT"
	ECHO "Commands may be abbreviated to one letter if you wish" 
	ECHO "YOUR OPTIONS ARE 'LIST', 'DIR', and 'QUIT'" NOLINE
	SKIP >NIL: ?
	LAB LIST
	LAB L
	    LIST
	    SKIP BEGIN BACK
	LAB DIR
	LAB D
	    DIR
	    SKIP BEGIN BACK
	LAB QUIT
	    [do what you wish here, then cause the script to exit... ]  
	ENDSKIP
	; now comes the default, if nothing was recognized
	ECHO "YOU MUST CHOOSE ONE OF THE AVAILABLE COMMANDS"
	SKIP BEGIN BACK

So AmigaDOS HAS looping, and recognition of defaults, and more than
just YES/NO built into it.

About VARIABLES, well, there ARE environment variables recognized by
the IF command, and ways to do things uniquely based on which CLI
process is doing it (the <$$> option that substitutes the current
CLI process to form variable names that are unique to the running process.

Sam - to help me make the Amiga Companion a better book in this area, maybe
you'd be willing to tell me what else you think AmigaDOS is missing,
that might just be vague in someone's documentation.   Yes, there are
plenty of things that CSH and WSHELL address that are not in the DOS,
but it seems that there are things that ARE there that some folks may
not yet be aware of.  Please use my email address, I am interested in
getting to know what you "miss having" about AmigaDOS... I might not
be able to influence CBM to add them, but as shown above, SOME of what
you asked already seems to be there, with not much pain to access it.
What else, please?   I'll post to the net with answers if I can solve
similar problems.

(The first edition of the Amiga Companion does cover this topic in
more detail, and includes descriptions of many if not all of the
1.3 options in command-scripts).  Second edition will be even better,
I believe.  More examples, including explaining the startup-sequence
in English, and a lucid description of the EVAL command example in
the Enhancer docs.  Kinda neat example, actually.  Just needed
some explaining.

Rob Peck			{ <anywhere>... !uunet!ardent!rap }