Re: Ceiling function in Ada

[agate!howland.reston.ans.net!noc.near.net!inmet!spock!stt@ucbvax.Berkeley .EDU (Tucker Taft)]

In article <karen.734158490@lobo> 
  karen@lobo.canberra.edu.au (Karen George) writes:

>On the other hand, why wouldn't a high level language provide a
>function as basic as truncate.  This is an easy task at machine level,
>and is not an uncommon task.  . . .

In hindsight, it was a mistake in Ada 83 not to define
a standard package for support of floating point operations
such as truncate, ceiling, etc., as well as the elementary
functions.  At the time it was felt that there was not
a great need to standardize a lot of packages.  In more recent
years, language standards have devoted more and more "real estate"
to standard libraries.  In ANSI C, the standard libraries are
about half the standard.  In Common Lisp, of course, the standard
libraries are most of the standard (since there is almost no syntax
to speak of).

For Ada 9X, we have realized that standard packages can be just as
important as some bit of syntax, and a full set of primitive
and elementary functions for floating point types will be provided,
including Truncation, Ceiling, Floor, Rounding, Sin, Cos, ...
Hopefully this will avoid some of the wheel reinvention that
took place with Ada 83, and also encourage implementations to
map such standard operations directly to the appropriate hardware 
instructions.

In the meantime, there is a standard set of Generic Primitive Functions
that has been defined for Ada 83, and is progressing through the
ISO standardization process by itself.  Some vendors should be
supporting it already.

>Karen George 				Email: karen@lobo.canberra.edu.au
>Information Sciences and Engineering	Phone: 	+61 6 201 2430
>University of Canberra,	AUSTRALIA 	FAX:	+61 6 201 5227

S. Tucker Taft     stt@inmet.com
Ada 9X Mapping/Revision Team
Intermetrics, Inc.
Cambridge, MA  02138