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From: Ted Dennison <dennison@telepath.com>
Subject: Re: About conversions
Date: 2000/11/22
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In article <8vfjhn$t4e$1@nnrp1.deja.com>,
  Robert Dewar <robert_dewar@my-deja.com> wrote:
> In article <8vetq2$bkb$1@nnrp1.deja.com>,
> Why is it confusing? Simple, most people think of conversions
> as basically function calls, and it is peculiar to have a
> function call as an Lvalue. (peculiar in Ada as well, and indeed

I prefer to think of them as a kind of in-line compiler directive, in
effect saying "think of this object as really being of this type". I
generally tell this to others as well, since thinking of it as a
function call leads people to the erronious conclusion that the
conversion is liable to have some kind of subprogram-like overhead.

>From this point of view, *not* allowing it for "out" parameters would be
confusing. (And yes, to this way of thinking it is a bit odd that you
can't use it on the left side of an assignment).

> -14 mod 5

Not a chance. I don't think I've ever needed to use "mod" for negative
numbers, so I would definitely have to look it up. That's just a matter
of use though. If I had to do it all the time, I'm sure I'd know it just
as well as a heavy C coder knows how to properly use the "?" operator.

Pretty much the only time I ever use "mod" is to index into circular
data structures. Occasionly I'll use it to effect a bit mask on an
unsigned value. There's probably a use for applying it to signed values,
but I haven't encountered it in 11 years.

--
T.E.D.

http://www.telepath.com/~dennison/Ted/TED.html


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