Re: Ada access vs C/C++ pointers and references

[Ole-Hjalmar Kristensen <ole-hjalmar.kristensen@substitute_employer_here.com>]

>>>>> "KHD" == Keith H Duggar <duggar@mit.edu> writes:

    >> No. This is just syntax. "." would have worked just fine for
    >> dereferencing C/C++ pointers. I suspect the reason for using "->" was
    >> just to make it more visible that you are using a pointer.

    KHD> Originally in C "x->" was shorthand for "(*x)."

Yes, but strictly speaking, since the compiler *knows* x is a pointer,
it could just have two versions of ".", one which works on records,
and one which works on pointers. So the shorthand for "(*x)." could
just as well have been "x." But i'm completely happy with "->"

    KHD> However, in C++ "->" serves the very useful purpose of
    KHD> (via operator overloading) allowing smart pointer types
    KHD> and iterator types to have the same semantics of raw
    KHD> pointers in addition to allowing the usual member access.
    KHD> Thus

    iterator-> f()       //access f() in object "pointed" to
    smart_pointer-> f()  //access f() in object "pointed" to
    KHD> iterator.f()        //access f() in iterator object
    KHD> smart_pointer.f()   //access f() in smart pointer object

    KHD> Otherwise, if the pointed to type had a function named f
    KHD> and the iterator had a function named f which function would
    KHD> interator.f() access?

If C++ had allowed dispatching on the return value of a function
(operator) you could use a cast to resolve the ambiguity.

    KHD> How is this resolved in Ada?

By not allowing you to overload "." :-)
Which means that smart pointers do not look so similar to normal
pointers in Ada, of course.

    KHD> Also, I'm sure there were C compatibility constraints as well.

-- 
   C++: The power, elegance and simplicity of a hand grenade.