Re: C++ is complicated
On 21 Mar., 11:31, jacob navia <ja...@nospam.org> wrote:
Some people here argue that C++ is not overly complicated.
I am reading "C++ Templates, the complete Guide". There,
the authors say (page 15)
"The rules for this decision may become rather
complicated even without templates. In this section we
discuss overloading when templates are involved. If
you are not familiar with the basic rules of overloading
without templates please look at Appendix B, where we
provide a reasonable detailed survey of the overload
resolution rules".
Great. That Appendix is 12 pages long! And it is not
complete of course!
Every C++ programmer *must* know those rules but maybe
1% of them know the WHOLE set of rules because the human
mind is not adapted to absorbing tons of programming trivia.
THEN, it is obviously the task of the maintenance programmer
to debug all those cases where the byzantine rules go
completely in other direction that the poor programmer
intended, when some new code using indirectly those
overloaded functions is written, 2 years AFTER the original
programmer left.
The great majority of C++ programmers doesn't know *exactly*
what are they doing when do a simple thing like overloading
a function...
Is this really necessary?
Now, look at this "concept" concept again. (Sorry but I find
no other way of saying it)
Behind it is the need to declare a set of types so that
template arguments can be checked by the compiler. OK.
But wasn't *inheritance* supposed to define this stuff?
No. Inheritance indicates "is-a" relationships, while what is needed
is a "has-a" relationship.
If you make a standard "super-class" that describes a
concept, wouldn't it be necessary just that your class
INHERITS from that super class to be cleanly checked
in the template argument list? Why is it necessary to
introduce YET ANOTHER huge construct?
For several reasons, one being that inheritance does not solve the
problem. But even if it did, you would require an inheritance relation-
ship that would quickly be unmaintainable. Just imagine all those
properties you would have to define in order to even simple types: are
they default-constructible, assignable, copy-constructible, can you
compare them, do they have a "less-than" relationship a.s.o. Using
concepts, all old code would have to be thrown out if inheritance or
something like that were to be used instead.
/Peter