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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Why is abs an operator, not a function?
Date: Wed, 18 Oct 2006 21:45:24 -0400
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"Jerry" <lanceboyle@qwest.net> writes:

> Why is abs an operator and not a function? Just wondering.

An operator _is_ a function.  So the question really is, why is the name
of the abs function an operator symbol (a reserved word) rather than an
identifier?

In early (pre-1983) versions of Ada, Abs was not an operator -- just a
normal function with identifier Abs as its name.  I think it was changed
to make implementations easier -- implementations usually special-case
the overloading resolution for operator symbols, since they are so
heavily overloaded.  Maybe the fact that all predefined functions
are operators simplifies that.  Not a big deal, but it does have
a certain uniformity -- e.g. "not" is an operator symbol, too,
and works the same way as "abs".

> Is there no way to write a function abs() that, say, computes the
> absolute value of each of the components of a float array?

As others have pointed out, you can write a such an "abs" function.

If you want to call it like this:

    abs(X)

that's fine.

- Bob