Re: why still use C?

Brian Inglis wrote:
> "Mike Cowlishaw" <[EMAIL PROTECTED]> wrote:
> > Morris Dovey wrote:
> > > Never wanting to miss an opportunity to display my considerable
> > > ignorance, why not leave selection of floating point radix a
> > > compile/link option? I've been thinking back over all the
> > > financial code I've ever written/seen and can't think of any
> > > instance where use of more than a single floating point radix
> > > made any sense at all. Why not simply use the type names we
> > > already have?
> >
> > This would mean that one could never have both binary and decimal
> > FP data in the same program/structure.
>
> This is a very good idea -- mixing binary, decimal (and hex) FP 
> formats in a structure or a set of related modules is a very bad
> idea -- unless the radix can be detected at the hardware level.

Well, to cite one place where both decimal and binary arithmetic will 
have to be supported concurrently, think of the major DBMS.

They typically support a FLOAT type that is based on a C-style binary 
double type, and they also typically support a DECIMAL type that is 
based on a (proprietary) software decimal floating point package. 
When hardware decimal types are provided, backwards compatibility 
requirements (a very heavy chain shackling the legs of those who have 
to implement the DBMS) will require the existing code - both binary 
and decimal - to continue to work as now, warts and all, while new 
data types are added to work with the new standard IEEE 754R decimal 
data types.  Fun will be had determining the rules of mixed mode 
arithmetic.  For backwards compatibility, existing code will continue 
to work unchanged, but new code using new expressions and the new 
types will use the new decimal arithmetic.  (That means, amongst other 
things, that we may need a new notation to write a new-style decimal 
literal value, though there's a chance that the existing rules can be 
adapted to suit - such as the constant is DECIMAL unless one of the 
other operands is a new-style decimal type.)

I doubt that DBMS will be the only such programs - spreadsheets might 
be another, for example (though maybe not; who knows?).  Scripting 
languages such as Perl migh be another example - or maybe not.  Such 
specialized programs are likely to be in the minority, but it will not 
be a negligible minority.

--
Jonathan Leffler                   #include <disclaimer.h>
Email: [EMAIL PROTECTED], [EMAIL PROTECTED]
Guardian of DBD::Informix v2003.04 -- http://dbi.perl.org/
--
comp.lang.c.moderated - moderation address: [EMAIL PROTECTED]