Newsgroups: comp.lang.c++
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Can I hide data from my compiler?
Message-ID: <1989Mar28.170031.20729@utzoo.uucp>
Organization: U of Toronto Zoology
References: <10133@bloom-beacon.MIT.EDU>
Date: Tue, 28 Mar 89 17:00:31 GMT

In article <10133@bloom-beacon.MIT.EDU> sorensen@hstbme.mit.edu.UUCP (Gregory Sorensen) writes:
>Specifically, I'd like routines which I can pass a data object
>made up of, say, floats or shorts, and use the same identical
>code to process either, although I won't know _until run time_
>whether the data is made up of floats or shorts.  Is there a way
>to do this other than defining functions for each data object?

Basically, no, although some languages (not C++) will do some of the
work of defining the functions for you.  The "same identical code" is
not identical at the machine level:  different machine instructions
are used to manipulate the different data types, so there *have* to be
separate functions, or the equivalent, down there somewhere.  C++ lets
you hide this from the outside world, and clever use of the C preprocessor
might largely mechanize generating the functions, but basically C++ as it
is currently defined isn't a lot of help when it comes to writing the
code itself.  You're going to have to consult some separate indication
of what the data type is, and then invoke a suitable chunk of code.
-- 
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