Re: [boost] Generic type inferencer function?

Subject: Re: [boost] Generic type inferencer function?
From: Nat Goodspeed (nat_at_[hidden])
Date: 2015-12-21 09:14:24

On Fri, Dec 18, 2015 at 11:50 AM, Nevin Liber <nevin_at_[hidden]> wrote:

> On 18 December 2015 at 10:37, Stefan Seefeld <stefan_at_[hidden]> wrote:

>> On 18.12.2015 11:20, Nat Goodspeed wrote:

>> > Am I overlooking a generic boost::make<something>() of this general form?

>> Given the small amount of code potentially to be reused, what would be
>> the advantage of having a generic version ? The goal of abstraction
>> should be clarity, but more often than not, generalizing code rips off
>> not only unnecessary details but also its meaning, making the code
>> harder, not easier, to understand.

> I disagree.  The make_* functions are just noise, and I'd love to see a
> generic one.  While return type deduction has made it somewhat easier to
> write these functions, a generic one would be superior.

Nevin speaks truth: the make_SomeTemplate() functions in our code base
are just boilerplate.

More importantly, encountering make_SomeTemplate() in the code
*increases* the cognitive load on the maintainer. What does
make_SomeTemplate() do? Oh: it returns an instance of
SomeTemplate<deduced args>. Every such call requires an indirection:
the maintainer must look up make_SomeTemplate() to discover its role.

If we introduce a std::make() template function, that becomes part of
the maintainer's working vocabulary. S/he only needs to look it up
*once*.

You could reasonably argue that a consistent naming convention
(make_SomeTemplate() should surely return an instance of SomeTemplate)
nearly eliminates the cognitive burden. And you'd almost be right --
if we could trust that no such function ever snuck in any side
effects.  :-(

I would counter that std::make<SomeTemplate>() is an even clearer
"naming convention." Moreover, I could be pretty confident that
std::make() would have no undocumented side effects.

I applaud Vicente's work at
https://github.com/viboes/std-make

Vicente, would you be willing to float the library via Boost?