Re: C++ reluctant to overload function

On 13 okt, 18:59, spop...@speedymail.org (Steve Pope) wrote:


I do not really see why you need them as overloads but hopefully you
tell the reason.

Lets first see what we have. There are several sin() in current C++.
1) In <complex> there is such std::sin():

 namespace std
 {
     template<class T> complex<T> sin(const complex<T>& x);
 }

2) In <valarray> there is such std::sin():

 namespace std
 {
     template<class T> valarray<T> sin(const valarray<T>&);
 }

3) In <cmath> there are such sin():

 double sin(double);
 float sin(float);
 long double sin(long double);

Lets now see solutions.

1) These are all usable side-by-side. Just call ::sin() for double,
float and long double or std::sin() for valarray<T> and complex<T>.

2) If you want to define your own sin in your scope (namespace) and
have the C++ sin variants also there as overloads:

 #include <complex>
 #include <valarray>
 #include <cmath>

 namespace stevemath
 {
     using ::sin;
     using std::sin;
     vector<double> sin(vector<double> x);
 }

3) If you want them to be all useful as overloads in a global
namespace then that is bad idea to burden global namespace but also
doable:

 #include <complex>
 #include <valarray>
 #include <cmath>
 using std::sin;
 vector<double> sin(vector<double> x); // Steves sin

So what is so difficult about it?


e.

I do not understand ... why you need them all sins as overloads of
each other. If there is reason then i don not understand how can it be
so good i have not met it but you desire it without indicating it?

Majority would really hate if some of thousands of functions from
<windows.h> or other place like that started to compete in overload
resolution with member functions within their classes or with
functions within their namespace and cause typos to compile for
confusing results. Describe the poor design choice you are steered
towards. For me C++ is as liberal as it can only get when choices of
paradigms, idioms or design patterns are under discussion.