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D - Circular Imports

reply Deja Augustine <Deja_member pathlink.com> writes:
I was curious what happens in the following situation:

a.d
---
import b;

class A
{
B x;
}

---
b.d
---
import a;

class B
{
A x;
}


it didn't generate any compile-time errors, so I'm wondering what exactly
happens with it.
Mar 18 2003
parent reply Burton Radons <loth users.sourceforge.net> writes:
Deja Augustine wrote:

 I was curious what happens in the following situation:
 
 a.d
 ---
 import b;
 
 class A
 {
 B x;
 }
 
 ---
 b.d
 ---
 import a;
 
 class B
 {
 A x;
 }
 
 
 it didn't generate any compile-time errors, so I'm wondering what exactly
 happens with it.



D, unlike C, splits semantic phases into a set of stages.  In the 
initial parsing it sees B and A fields in one and the other and doesn't 
try to interpret it; it's only in the semantic phases that it links them 
together.  It should also be possible to do this:

    class B : A { }
    class A { }

And this:

    class A { B x; }
    struct B { }

And this:

    A x = { 1, 2 };
    struct A { int a, b; }
Mar 18 2003
parent reply "Deja Augustine" <DejaD scratch-ware.net> writes:
"Burton Radons" <loth users.sourceforge.net> wrote in message
news:b595vf$25cs$1 digitaldaemon.com...

 Deja Augustine wrote:

 I was curious what happens in the following situation:

 a.d
 ---
 import b;

 class A
 {
 B x;
 }

 ---
 b.d
 ---
 import a;

 class B
 {
 A x;
 }


 it didn't generate any compile-time errors, so I'm wondering what







 happens with it.



 D, unlike C, splits semantic phases into a set of stages.  In the
 initial parsing it sees B and A fields in one and the other and doesn't
 try to interpret it; it's only in the semantic phases that it links them
 together.  It should also be possible to do this:

     class B : A { }
     class A { }

 And this:

     class A { B x; }
     struct B { }

 And this:

     A x = { 1, 2 };
     struct A { int a, b; }



Yeah, that's not really what I was asking.  What I wanted to know was, can
someone, using my initial example, write a chunk of code like so:
-----
 c.d
-----
import a;

B var;

int main()
{
  var.x = new A();
  var.x.x = new B();
  var.x.x.x = new A();
}

on into infinity
Mar 18 2003
parent reply Burton Radons <loth users.sourceforge.net> writes:
Deja Augustine wrote:

 Yeah, that's not really what I was asking.  What I wanted to know was, can
 someone, using my initial example, write a chunk of code like so:
 -----
  c.d
 -----
 import a;
 
 B var;
 
 int main()
 {
   var.x = new A();
   var.x.x = new B();
   var.x.x.x = new A();
 }
 
 on into infinity



Yes, because they're classes.  If they were struct, it would be a 
circular field error.
Mar 18 2003
parent "Deja Augustine" <DejaD scratch-ware.net> writes:
"Burton Radons" <loth users.sourceforge.net> wrote in message
news:b59753$263r$1 digitaldaemon.com...

 Deja Augustine wrote:

 Yeah, that's not really what I was asking.  What I wanted to know was,







 someone, using my initial example, write a chunk of code like so:
 -----
  c.d
 -----
 import a;

 B var;

 int main()
 {
   var.x = new A();
   var.x.x = new B();
   var.x.x.x = new A();
 }

 on into infinity



 Yes, because they're classes.  If they were struct, it would be a
 circular field error.



Okay.

As a side note treat for anyone reading this, I hope to have DEnv Beta 1.2f
out sometime this week.
Mar 18 2003