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000169_icon-group-sender_Tue Dec 31 15:20:41 2002.msg
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Return-Path: <icon-group-sender>
Received: (from root@localhost)
by baskerville.CS.Arizona.EDU (8.11.1/8.11.1) id gBVMIg617195
for icon-group-addresses; Tue, 31 Dec 2002 15:18:42 -0700 (MST)
Message-Id: <200212312218.gBVMIg617195@baskerville.CS.Arizona.EDU>
From: ernobe <ernobe@msn.com>
X-Newsgroups: comp.lang.icon
Subject: Re: Scanning question
Date: Tue, 31 Dec 2002 02:15:39 +0200
X-Newsreader: MicroPlanet Gravity v2.50
To: icon-group@cs.arizona.edu
Errors-To: icon-group-errors@cs.arizona.edu
Status: RO
>
> > if the 'then' clause fails in the conjunction, does the 'if'
> > clause itself fail?
>
> Yes. Depending on the "if" condition, the "then" or the "else" part is
> executed. The outcome of the entire statement will be the outcome of the
> chosen "then" or "else" part. If the else part is missing, it is like a
> failure - effectively a missing else part generates zero results which will
> be a failure that will force backtracking.
>
> In either situation, if the "then" or "else" part generates results, that is
> the result of the entire "if" statement. Note that the condition is never
> resumed - it is driven to produce ANY result so that the "then" or the
> "else" part can be selected but after that it is finished.
>
Thank-you for your very informative post. This particular issue with the if
statement was the cause of my problems. I suspect that I must be missing
informatin on facts as basic as this, since I hadn't come across it in the
documentation. Perhaps it is something one learns in the first year of
computer science courses in the university. I found Icon on the Web after
nearly a year of searching for and trying several languages, particularly Forth
and Euphoria. I have the general impression that most of the documentation is
written for advanced students. Perhaps part of it is intentional in order not
to share information that may be used maliciously. Just today I found a
website of a hacker who has one of the best tutorials on Dos programming that
I've seen so far. I've noticed the similarity of some of Icons functions with
the Dos functions that are available in my Windows 2000 OS, but proper or even
basic information as to how to use these commands is totally missing. I'd
appreciate it if anyone could direct me to an appropiate source.
--
my esoteric links:
http://www.costarricense.cr/pagina/ernobe/