[cfe-dev] Don't help the compiler!

[Nicola Gigante]

Hi.

> Il giorno 26/gen/2015, alle ore 10:15, David Chisnall <David.Chisnall at cl.cam.ac.uk> ha scritto:
> 
> The latter form seems less readable.  The fact that a floating point literal is a double unless suffixed with f is something that is rarely important for developers to remember, so this extra piece of information increases the cognitive burden when reading the code.
> 
> The goal of the former form is not to 'help the compiler', it is to help the poor sap who has to maintain this code in a couple of years.
> 

While this might be true, the point of std::make_pair is to deduce the type of the arguments.
If one wants to explicitly specify the types, he can simply do:

auto p = std::pair<int,double>(42, 3.14);

or

std::pair<int,double> p{42, 3.14};

which are also a few less keystrokes. It doesn’t need make_pair, which is perfectly redundant if
you don’t want it to deduce the types.

Also in general, explicitly specifying the types of arguments of a template function which is
designed with deduction in mind, seems to me bad practice, because it’s fragile if one
change the arguments but not the types of vice-versa, and could break or slowdown things
when perfect-forwarding comes in the mix.

This example exacerbates the issue:
auto p = std::make_unique<T, ArgT1, ArgT2, ArgT3>(arg1, arg2, arg3); // Please don’t.

So IMHO a check to tell the inexperienced user about this redundancy is very helpful.

> David


Bye,
Nicola