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Date: Fri, 21 Jun 2013 22:42:45 +0200
From: Georg Bauhaus <rm.dash-bauhaus@futureapps.de>
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Subject: Re: null declarative parts
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Date: 2013-06-21T22:42:45+02:00
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On 21.06.13 20:58, Robert A Duff wrote:

> You probably like the syntax "(null record)" for an empty aggregate;
> I would prefer "[]" (with square brackets).  I might leave a blank,
> to emphasize its emptiness -- "[ ]" -- but that's as far as I'd go.

One meaning of [] is good, many meanings are bad.

[]-s added for null records would, I fear, (1) increase the puzzlement
of programmers in the popular languages market where we regularly
need to learn "new" languages that have [] but differ about its meaning.
(Just wasted 3 hours on forgetting that a deletion operator applied
to a [] (a list) and an index will remove the element, but not
the slot (will not splice), which is unlike what it does with
a table and an "index". Which is unlike what it does to whatever
[] means in C++, and don't mix that with Python, Javascript,
or the list notations of MLispThica.)

(2) A SIGCSE paper convincingly argues (against PL Turing) that it
is a good thing to have [] and {} and other brackets besides () to
denote different things, unlike Ada. But I'd hope that the used of
[] converges to only one or two commonly accepted meanings of [].