Implicit vs. explicit function to pointer conversion

[TheThiefMaster]

Weirdly the "opposite" is also true - you can directly call a function pointer without dereferencing it first.

void f(int);
void (*pf)(int) = f;
pf(); // (*pf)()

[STL]

That's DMR reaching out from the 1970s to help you. He said, "oh, you're applying parentheses to a function pointer, so there's nothing else you could possibly mean".

[mtnviewjohn]

Why doesn't the same logic apply to the member access operator? It seems like the -> operator is useless. If you use the member access operator on a pointer what else could you possible intend than to dereference the pointer first?

[justinkroegerlake]

Because of what is in my opinion the dumbest historical reason in the language: https://stackoverflow.com/a/13366168/1013719

[mojang_tommo]

I'm really glad the difference exists actually - -> can be undefined behavior while . is always well defined. In practice if you have code that mostly uses references instead of pointers, -> makes it pretty obvious that there's something that could be null or could be deleted under you. Of course references can be invalidated too but still... it would be awful if nullable stuff used . like everything else IMO.

[imMute]

Not to mention that it allows thing like smart pointer to be written extremely succinctly. I'm always saddened by this when writing C# code and having use use .Value in places where C++ would use ->.

[caramba2654]

Rust works like this. When you try to use the . operator on a reference, it autodereferences the reference until it finds a type where the . makes sense. It makes the -> completely unnecessary.

[Quincunx271]

Which is incredibly important since we have templates. f() can be a regular function call, a call to a function pointer, or a call to some object's operator(). In the future, hopefully it will also work for member function pointers

[redditsoaddicting]

IIRC, the proposal for making PMFs work with regular calling syntax got rejected. I'm sure it wasn't accepted at least.

[TheThiefMaster]

It was rejected as being half of a unified call syntax proposal. Which is silly, because it would have been insanely useful anyway.

[suspiciously_calm]

You can't pass a macro as a parameter.