RE:CINT bug(s)

Masaharu Goto (MXJ02154@nifty.ne.jp)
Sun, 18 Apr 1999 12:54:47 +0900


Jacek,

Thank you for reporting these problems.
I analyzed the problem. Both are CINT syntax limitation.
Please use simple expression.

I'll think if those can be fixed, however, I can not put priority on fixing
this kind of complex expression which you can easily find simpler and
clearer ones. CINT is not aimed to be 100% C/C++ compliant interpreter.

NOT RECOMMENDED SIMPLE EXPRESSION RECOMMENDED
return a=b; vs a=b; return a;
f()[1] = val; vs int* tmp=f(); tmp[1]=val;

Best Regard,
Masaharu Goto

1) returning reference of assignment expression.
In following class XYZ, member function x and z returns reference.

class XYZ {
public:
int p_x;
int p_y;
int p_z;

int &x(int xx) {cout << "xx -> " << xx << " p_x -> " << p_x << endl;
return p_x=xx;}
int y(int &yy) {cout << "yy -> " << yy << " p_y -> " << p_y << endl;
return p_y=yy;}
int &z(int &zz) {cout << "zz -> " << zz << " p_z -> " << p_z << endl;
return p_z=zz;}
};

The problem is in 'return p_x=xx;'. CINT returns reference to xx. This
causes the problem. Please separate assignment and return statement.

p_x=x;
return p_x;

2) In following source, XYZ::x , y, z returns pointer. In main function,
[] operator is used for the return value of the function.

f()[0] = value;

Unfortunately this kind of syntax is not supported in CINT. Please rewrite
this as

int *tmp = f();
tmp[0] = value;

-------------------------- trial2.cxx BEGIN --------------------------
#include <stream.h>

class XYZ {
public:
int p_x[10];
int p_y[20];
int p_z[30];

int *x() {return p_x;}
// int *y() {return p_y;}
int *y() {cout << "*p_y -> " << *p_y ;*p_y=6;cout << " -> " << *p_y <<
endl;return p_y;}
int *z() {return p_z;}

XYZ() {return;}
~XYZ() {return;}
int *x(int xx) {cout << "xx -> " << xx << " *p_x -> " << *p_x <<
endl;p_x[0]=xx;return p_x;}
int *y(int yy) {cout << "yy -> " << yy << " *p_y -> " << *p_y <<
endl;p_y[0]=yy;return p_y;}
int *z(int zz) {cout << "zz -> " << zz << " *p_z -> " << *p_z <<
endl;p_z[0]=zz;return p_z;}
};

main()
{
XYZ *xyz = new XYZ;

cout << "donald duck" << endl;

xyz->x(1)[0] = 10; cout << "xyz->x(1)[0] = 10 -> " << *xyz->p_x << endl;
xyz->y(2); cout << "*xyz->y(2) -> " << *xyz->p_y << endl;
xyz->z(3)[0] = 30; cout << "xyz->z(3)[0] = 30 -> " << *xyz->p_z << endl;

xyz->x()[0] = 4;
xyz->y()[0] = 5; cout << "*xyz->y() = 5 -> " << *xyz->p_y << endl;

cout << *xyz->x() << " " << *xyz->y() << " " << *xyz->z() << endl;

cout << "miki mouse" << endl;

}