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| Subject | Re: query interface | |||||||||||||||||||||
| From | Jarrett Billingsley <jarrett.billingsley@gmail.com> | |||||||||||||||||||||
| Date | Wed, 21 Jan 2009 11:11:28 -0500 | |||||||||||||||||||||
| Newsgroups | digitalmars.D.learn | |||||||||||||||||||||
On Wed, Jan 21, 2009 at 10:30 AM, Qian Xu <quian.xu@stud.tu-ilmenau.de> wrote: > Hi All, > > can D check, whether a class A an Interface B supports? > > like: > > if (supports(class_A, intf_B)) > { > cast(intf_B) (class_A).hello(); > } At compile time, like Frits said, you can use is(class_A : intf_B). At runtime, you can use cast(intf_B)someInstance. That returns 'null' if someInstance does _not_ inherit from intf_B. if(auto i = cast(intf_B)instanceOfA) i.hello(); | ||||||||||||||||||||||
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