C++ violates, what does it mean?

[siavoshkc]

C++ violates the separation of contract and implementation when inline functions are declared.
Ada does not.

What does it mean?

[whiteflags]

This is a class contract:

class X {
  public:
    X(int);
    ~X();
    int foo();
    int get_int();
    void set_int();
  private:
    int x;
};

Say for example that I wanted to inline foo(), for some reason. I could define the function in the class contract to achieve that; therefore, I've violated a common style guideline that states you should keep implementation of a class and definition of a class separate. I find it a weak argument, but that's me.

In fact the whole way that page makes its point bothers me.

[siavoshkc]

In fact the whole way that page makes its point bothers me.

Of course it is Ada site. ;-)

[Mario F.]

Particularly considering we can still define the function outside the class body. Inlined or not.

Besides...

55. C++ is widely used.
Ada is not.

[whiteflags]

C++ does that! Ada does this!

<unstated>And Ada must be better because of this!</unstated> Okay, but write something the critical reader can appreciate.

[Salem]

> C++ violates the separation of contract and implementation when inline functions are declared.
That's the least of the problems - the fact that C++ classes have to list their private parts in the class for all the world to see should be more of a concern.

I suppose you could do this

class foo_private;
class foo {
  public:
    foo();
    ~foo();
  private:
    foo_private *private;
};

Where only foo.cpp implementation files get to include foo_private.h and all the things it offers.

On the plus side, this may help to stop rebuild cascades when you change some base class and EVERYTHING has to be rebuilt because of it.

[laserlight]

That "Comparison of Ada and C++ Features" was done before C++ was standardised, so it is out of date.

[CornedBee]

I suppose you could do this

Also known as the PIMPL idiom and widely used.