• terranium <spam here.lot> May 08 2008
• BCS <ao pathlink.com> May 08 2008

BCS Wrote:

 The point is that offtent a failed cast is not an indecation of an 
 error. For instance code like this
 
 class A {}
 class B1 : A {}
 class B2 : A {}
 
 void foo(A a)
 {
    if(auto b = cast(B1)a) {}
    else if(auto b = cast(B2)a) {}
    else {}
 }


I see polimorphism should help here.

Reply to terranium,

 BCS Wrote:
 
 The point is that offtent a failed cast is not an indecation of an
 error. For instance code like this
 
 class A {}
 class B1 : A {}
 class B2 : A {}
 void foo(A a)
 {
 if(auto b = cast(B1)a) {}
 else if(auto b = cast(B2)a) {}
 else {}
 }


 


dosn't always work

module third.party.lib;
class A {}

module my.lib.one
class B1 : A { int newFn(){...}}

module my.lib.teo
class B2 : A { char somthingNew(char[] c){...}}

void foo(A a)
{
  if(auto b = cast(B1)a)
    b.newFn();
  else if(auto b = cast(B2)a)
    b.somthingNew("hello");
  else
    throw new Error("a isn't a B1 or B2");
}