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000038_icon-group-sender _Fri Oct 23 16:46:21 1992.msg
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1993-01-04
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Received: by cheltenham.cs.arizona.edu; Wed, 28 Oct 1992 09:34:08 MST
Date: 23 Oct 92 16:46:21 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!malgudi.oar.net!caen!spool.mu.edu!darwin.sura.net!paladin.american.edu!news.univie.ac.@!hp4at!mcsun!Germany.EU.net!sbsvax!coli-gate.coli.uni-sb (Stephen Spackman)
Organization: DFKI Saarbruecken GmbH, D-W 6600 Saarbruecken
Subject: Re: confusing errors
Message-Id: <SPACKMAN.92Oct23174836@disco-sun6.dfki.uni-sb.de>
References: <1992Oct12.140817.25199@midway.uchicago.edu>
Sender: icon-group-request@cs.arizona.edu
To: icon-group@cs.arizona.edu
Status: R
Errors-To: icon-group-errors@cs.arizona.edu
In article <1992Oct15.155939.2562@midway.uchicago.edu> goer@ellis.uchicago.edu (Richard L. Goerwitz) writes:
|stephen@acm.org writes:
|>|If anybody find the Icon tokenizer interesting (automatic semicolon inser-
|>|tion is really a great idea - why don't all languages do it?), then here's
|>|a fun program.
|>
|>Makes about as much sense as automatic plus insertion or automatic
|>atanh() insertion, if you ask me.
|
|I didn't ask, Stephen, but since you interject I respond with a basic
|remark about tokens and their semantics: Some terminals map to nodes
|in the abstract syntax tree; some only demarcate expressions. When and
|if they are superfluous, they should be eliminated, as long as doing so
|does not render the language more opaque.
But but but. The semicolon operator DOES have semantics: it explicitly
evaluates and discards its left argument and returns its right! It's the
most drastic operator in the book! Now *parentheses*, I grant, don't do
anything at abstract syntax. Wanna make THOSE optional?
|Opacity is a subjective judgment, of course, so let's check to see if
|you know Icon in the first place. Can you illustrate where automatic
|semicolon insertion might render Icon source code less readable, or
|introduce unexpected behavior? I'm waiting....
Nono, not my point. It reduces regularity in the language, limits the
ease with it can be read and written automatically, and increases the
potential for errors to be introduced during the editing process.
Readability and unexpected behaviour are not the only criteria -
otherwise we'd use natural language prose cross-checked by requiring
submission of source in english and two other natural languages related
at a time depth of no less than three thousand years....
Now Icon isn't a language whose syntax fits on half a page anyway, so
perhaps I shouldn't kick; but I can't help feeling that we should
*start* demanding that languages be reasonably straightforward....
stephen