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/**
* @file mystring.cpp Example of extending GiNaC: writing new classes
*/
#include <iostream>
#include <string>
#include <stdexcept>
using namespace std;
#include <ginac/ginac.h>
using namespace GiNaC;
class mystring : public basic
{
GINAC_DECLARE_REGISTERED_CLASS(mystring, basic)
public:
mystring(const string &s);
ex eval(int level) const;
private:
string str;
protected:
void do_print(const print_context &c, unsigned level = 0) const;
};
GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(mystring, basic,
print_func<print_context>(&mystring::do_print))
// ctors
mystring::mystring() { }
mystring::mystring(const string &s) : str(s) { }
// comparison
int mystring::compare_same_type(const basic &other) const
{
const mystring &o = static_cast<const mystring &>(other);
int cmpval = str.compare(o.str);
if (cmpval == 0)
return 0;
else if (cmpval < 0)
return -1;
else
return 1;
}
// printing
void mystring::do_print(const print_context &c, unsigned level) const
{
// print_context::s is a reference to an ostream
c.s << '\"' << str << '\"';
}
/**
* evaluation: all strings automatically converted to lowercase with
* non-alphabetic characters stripped, and empty strings removed
*/
ex mystring::eval(int level) const
{
string new_str;
for (size_t i=0; i<str.length(); i++) {
char c = str[i];
if (c >= 'A' && c <= 'Z')
new_str += tolower(c);
else if (c >= 'a' && c <= 'z')
new_str += c;
}
if (new_str.length() == 0)
return 0;
else
return mystring(new_str).hold();
}
int main(int argc, char** argv)
{
ex e = mystring("Hello, world!");
cout << is_a<mystring>(e) << endl;
cout << ex_to<basic>(e).class_name() << endl;
cout << e << endl;
ex another = pow(mystring("One string"), 2*sin(Pi-mystring("Another string")));
cout << another << endl;
return 0;
}
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