On Thu, 14 Mar 2013 11:38:52 -0400 Andrei Alexandrescu <seewebsiteforem...@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 <seewebsiteforem...@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.
