"Vincent Cantin" <MY***************@astrocorp.com.tw> wrote in message news:2k************@uni-berlin.de...
I have a class defined by a template which needs to "say" its type to the
user via string.
As an example, here is the class that I want to fix :
template<class T> class Container : public Serializable
{
public:
T value;
static string classIdentifier;
string& getClassIdentifier();
};
template <class T> string& Container<T>::getClassIdentifier()
{
return classIdentifier;
}
For now, the only way I found to initiliaze the string is with :
string Container<bool>::classIdentifier("Container<bool>" );
string Container<char>::classIdentifier("Container<char>" );
string Container<short>::classIdentifier("Container<short >");
string Container<int>::classIdentifier("Container<int>");
string Container<float>::classIdentifier("Container<float >");
string Container<double>::classIdentifier("Container<doub le>");
string Container<unsigned char>::classIdentifier("Container<unsigned
char>");
string Container<unsigned short>::classIdentifier("Container<unsigned
short>");
string Container<unsigned int>::classIdentifier("Container<unsigned int>");
string Container<unsigned float>::classIdentifier("Container<unsigned
float>");
string Container<unsigned double>::classIdentifier("Container<unsigned
double>");
This solution works for the basis types, but now imagine that I would like
to use my template class with another type which is not in the list ? The
compiler will say that my static variable is not defined :-(
I think there might be a way to do it with a macro but I don't know how to
do. Does someone here have a solution ?
Vincent
If you are using GNU g++ version 3.3
the following method can be used.
========= C++ code : foo.cpp : BEGIN =========
#include <string>
#include <iostream>
using namespace std;
template<class T>
class Container
{
public:
static const string classIdentifier;
static string getClassIdentifier();
};
template<class T>
string Container<T>::getClassIdentifier()
{
const string str0 (__PRETTY_FUNCTION__);
string str1 (str0.substr (0, str0.find ("<")));
str1 = str1.substr (str1.find_last_of (' ') + 1);
string str2 (str0.substr (str0.find_last_of (' ') + 1));
str2 = str2.substr (0, str2.size() - 1);
return str1 + "<" + str2 + ">";
}
template<class T>
const string Container<T>::classIdentifier(Container<T>::getCla ssIdentifier());
class Foo {};
template<class T>
class Bar {};
int main ()
{
cout << Container<bool>::classIdentifier << endl;
cout << Container<int>::classIdentifier << endl;
cout << Container<Foo>::classIdentifier << endl;
cout << Container<Bar<int> >::classIdentifier << endl;
cout << Container<Bar<Foo> >::classIdentifier << endl;
cout << endl;
cout << Container<bool>().classIdentifier << endl;
cout << Container<int>().classIdentifier << endl;
cout << Container<Foo>().classIdentifier << endl;
cout << Container<Bar<int> >().classIdentifier << endl;
cout << Container<Bar<Foo> >().classIdentifier << endl;
return 0;
}
========= C++ code : foo.cpp : END ===========
========= Compilation & Run : BEGIN =========
$ g++ --version
g++ (GCC) 3.3.1 (cygming special)
[snip]
$ g++ foo.cpp
$ a
Container<bool>
Container<int>
Container<Foo>
Container<Bar<int>>
Container<Bar<Foo>>
Container<bool>
Container<int>
Container<Foo>
Container<Bar<int>>
Container<Bar<Foo>>
========= Compilation & Run : END ===========
--
Alex Vinokur
http://mathforum.org/library/view/10978.html http://sourceforge.net/users/alexvn 
