C++ guys hate static_if?

[Nick Sabalausky]

On Thu, 14 Mar 2013 11:38:52 -0400
Andrei Alexandrescu <SeeWebsiteForEmail at erdani.org> wrote:

> On 3/14/13 11:05 AM, monarch_dodra wrote:
> > Having to instantiate a template just to check to make sure it is
> > semantically correct is a huge pain.
> 
> I'm not sure about that. The way I see it, no code should be not 
> delivered without being unittested. Ubiquitous unittesting is now 
> mainstream. The way I see it, a type system on top of templates would 
> only help people who don't write unittests.
> 

What the hell is this, a JS/Python forum all of a sudden? You're
literally making the exact same argument as "We don't need no steenkin'
static type checking."


On Thu, 14 Mar 2013 13:07:16 -0400
Andrei Alexandrescu <SeeWebsiteForEmail at erdani.org> wrote:
> 
> Very simple. Traditionally there's two crucial epochs known as 
> compilation time and run time. (There's some minor distinctions like 
> link time etc.) The whole notion of concepts and other type systems
> for templates is predicated on three crucial epochs: library
> compilation time, library user compilation time, and run time. The
> logic goes, someone writes a generic library and wants to distribute
> it to users. Users shouldn't ever see bugs caused by e.g. typos in
> the library.
> 
> So the crowd that use meta-type systems is formed of library writers
> who want to distribute libraries without ever instantiating them. I
> don't think that's a good crowd to cater for.
> 
> I've been surprised to figure how many people don't get this flow, or 
> only have a vague image of it. Although meta-types are arguably "the 
> right thing" to do, they're a lot less attractive once it's clear
> what scenarios they help.
> 

That's because the flow is completely wrong. Particularly so in the
context of a static-typed language. Where do I start?:

- The branch of the discussion you're replying in has nothing to do
  with meta-types and yet you seem to be arguing on the false dichotomy
  of "Introduce meta-types vs no static checks on templates without
  instantiation". Please check the link in Don's post a few replies up.

- "...library writers who want to distribute libraries without ever
  instantiating them..." is a hyperbolic strawman. Do you really expect
  us to believe that you and other respectable coders, let alone
  ordinary coders,  *never* miss an instantiation? Of course not, and
  we both know that. So don't insult us by trying to paint this out as
  some "it only helps/encourages the lazy" bullshit.

- We're talking a static-typed language here. The philosophy that "it's
  better to catch a whole class of errors as early regardless of
  whether the code in question gets used than to delay the check until
  a point where it may or may not get caught" is already a given. We're
  not Python here.