Re: ADA Popularity Discussion Request

[kevin.cline@gmail.com (Kevin Cline)]

Georg Bauhaus <sb463ba@l1-hrz.uni-duisburg.de> wrote in message news:<choh37$8i9$1@a1-hrz.uni-duisburg.de>...
> Kevin Cline <kevin.cline@gmail.com> wrote:
> : If you want bounded types in C++ it's easy enough to write a template
> : class:
> 
> True, but it is not quite the same thing, is it? You can write bounded
> types in C. Yet, they don't become C language types, with ISO definded
> semantics beyond what you'd expect for any user defined type.

The Ada designers evidently thought arrays were really really
important, because they provided elaborate language facilities to
support array-based programming.  The C language designers instead
created a small but useful language.  Stroustrup didn't spend much
effort on arrays, perhaps because he didn't think they were so
important.  Instead he tried to make it easy to define and use new
types as easily as one could use the fundamental types.

> Does the C++ standard directly address the behavior of handwritten
> bounded numbers? How many lines of template code will it take
> to get the effect of
> 
>   type A is array(Some_Index_Type) of Foo;?

I don't know.  It could be done in C++ if Some_Index_Type had the
right properties.  But as a practical matter, no one seems to care, at
least no one in the C++ community.  I very rarely have any need or use
for a statically sized array.  Even if I did want a static array with
non-integer indexing, unless it's really important to shave 100
nanoseconds from the lookup time, a map will do just as well, and
that's the canonical solution in both C++ and Perl.

> #include <assert.h>
> 
> struct _bint {
>   long v;
>   int up, lo;
> };

This is quite ugly, not to mention inefficient.  But I would never
advocate use of C for writing an application of any size.