RFC: std.concepts

[Leandro Motta Barros via Digitalmars-d]

Looks very nice! I think I could make use of it. (Though I use D only
recreationally :-) )

LMB


On Sun, Oct 19, 2014 at 7:10 PM, Shammah Chancellor via Digitalmars-d <
digitalmars-d at puremagic.com> wrote:

> It was request that I create a NG thread about a module I was hoping to
> merge with phobos. (std.concepts)  Please take a look.
>
> Thanks in advance.
>
> -S
>
> Link to PR:
>
> https://github.com/D-Programming-Language/phobos/pull/2627
>
> Docs:
>
>
> bool isConcept(T, C, bool diagnostics = false, string errorPrefix = "")();
> Returns true if T supports the concept C. Note, templated member functions
> are not supported currently.
>
> Concepts should be defined as in the following example:
> ----
> class CInputRange(E) : Concept
> {
>         abstract void popFront();
>         @property abstract E front();
>         bool empty;
>
>         //Optional axioms function.  This will be checked if it compiles,
> and that it returns true if it does.
>         static bool axioms(T)()
>         {
>                 return true;
>         }
> }
>
> class CInfinite() : Concept
> {
>         static bool axioms(T)() {
>                 enum empty = T.empty;
>                 return !empty;
>         }
> }
>
> class CInfiniteInputRange(E) : CInputRange!E
> {
>         mixin CInfinite;
> }
> ---
>
> template conceptDiagnostic(R, string F, int L, C...)
> Prints error messages for why template instantiation failed.
>
> Examples:
> ---
> bool DoStuff(R)(R infRange) if ( isConcept!(R, CInfiniteInputRange!string))
> {
>         return true;
> }
>
> bool DoStuff(R)(R infRange) if ( isConcept!(R, COutputRange!string))
> {
>         return true;
> }
>
> //Example of using conceptDiagnostic
> bool DoStuff(R, string F = __FILE__, size_t L = __LINE__ )(R infRange)
> {
>         mixin conceptDiagnostic!(R, F, L, COutputRange!string,
> CInfiniteInputRange!string);
>         return false;
> }
> ---
>
> class Concept;
> Base class for Concepts. All Concepts should derive from this, or another
> concept.
>
>
>
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