Tricky C++

07. July 2014 · Categories: Software

One of the problems with C++ is that it has a very brittle syntax, meaning that it is easy to trip over subtle differences:

class D {
  D();
  D( int);
}
void test() {
  D a;
  D b( 1);
  D c();
}

class D {

D();

D( int);

}

void test() {

D a;

D b( 1);

D c();

}

In this code, what is c? Given the definition of b, it sure looks like a class instantiation, but it actually is a function declaration that returns a class D. This is a problem that could easily be solved by requiring a function declaration without a parameter to use void, as in:

class D {
  D( void);
  D( int);
}
void test() {
  D a;
  D b( 1);
  D c( void);
}

class D {

D( void);

D( int);

}

void test() {

D a;

D b( 1);

D c( void);

}

This is more verbose, but it is also more difficult to get wrong. I believe this is what will kill C/C++ in the future: the unwillingness to sacrifice some backward compatibility for a safer syntax, even if one could do a perfect automatic translation.