• llothar (3/3) Jul 11 2005 Sorry a simple yes/no question.
• Ben Hinkle (22/26) Jul 11 2005 yes. Running
• Mike Capp (20/21) Jul 11 2005 Yes, insofar as
• Walter (11/14) Jul 12 2005 d, so i
• Craig Black (4/21) Jul 12 2005 C++ is retarted and D is cool.
• Mike Capp (14/15) Jul 12 2005 Yes, up to a point.
• Sean Kelly (3/18) Jul 16 2005 I assume the same is true for the dtor as well?

llothar <llothar_member pathlink.com> writes:

Sorry a simple yes/no question.

Just theoretical evaluating the chance to move my project from eiffel to d, so i
would really like to see a "yes" here.

"Ben Hinkle" <ben.hinkle gmail.com> writes:

"llothar" <llothar_member pathlink.com> wrote in message 
news:dauhd9$1uv0$1 digitaldaemon.com...
 Sorry a simple yes/no question.

 Just theoretical evaluating the chance to move my project from eiffel to 
 d, so i
 would really like to see a "yes" here.

yes. Running
class A {
  this(){foo();}
  void foo(){printf("hi\n");}
}
class B :A {
  void foo(){printf("hi2\n"); super.foo();}
}
int main() {
  B b = new B;
  return 0;
}
printf "hi2" then "hi". The object vtable is initialized before the ctor is 
called. Initializers are also applied before the ctor is run:
class A {
  int x = 20;
  this(){printf("%d\n",x);}
}
int main(){new A; return 0;}
will print "20". 

Mike Capp <mike.capp gmail.com> writes:

In article <dauhd9$1uv0$1 digitaldaemon.com>, llothar says...
Sorry a simple yes/no question.

Yes, insofar as














prints "derived".

Personally I can't help feeling that this is rather unsafe, but then D (unlike
C++) will statically-initialize members to (hopefully safe) defaults before
calling any ctors.


just a theoretical problem.

"Walter" <newshound digitalmars.com> writes:

"llothar" <llothar_member pathlink.com> wrote in message
news:dauhd9$1uv0$1 digitaldaemon.com...
 Sorry a simple yes/no question.

 Just theoretical evaluating the chance to move my project from eiffel to

d, so i
 would really like to see a "yes" here.

Yes.

D constructors are passed a "fully formed" class object instance, with each
of its fields set to its corresponding default value. This includes the
pointer to the virtual function table pointer (vptr), which is set to the
most derived class' vtbl[].

This is unlike C++, where the fields are garbage, and vptr is set to the
vtbl[] of the constructor's class, rather than the vtbl[] of the most
derived class.

"Craig Black" <cblack ara.com> writes:

C++ is retarted and D is cool.

-Craig

"Walter" <newshound digitalmars.com> wrote in message 
news:db11j9$176k$1 digitaldaemon.com...
 "llothar" <llothar_member pathlink.com> wrote in message
 news:dauhd9$1uv0$1 digitaldaemon.com...
 Sorry a simple yes/no question.

 Just theoretical evaluating the chance to move my project from eiffel to

 d, so i
 would really like to see a "yes" here.

 Yes.

 D constructors are passed a "fully formed" class object instance, with 
 each
 of its fields set to its corresponding default value. This includes the
 pointer to the virtual function table pointer (vptr), which is set to the
 most derived class' vtbl[].

 This is unlike C++, where the fields are garbage, and vptr is set to the
 vtbl[] of the constructor's class, rather than the vtbl[] of the most
 derived class.

 

Mike Capp <mike.capp gmail.com> writes:

In article <db11j9$176k$1 digitaldaemon.com>, Walter says...
D constructors are passed a "fully formed" class object instance,

Yes, up to a point.

According to the class docs, "The invariant is checked when a class constructor
completes [... or ...] before a public or exported member is run". So what about
when a public method is called virtually from a base-class constructor? Is the
invariant checked before the constructor has run? 

If not, why not? The object is supposed to be "fully formed", isn't it?

If so, the derived class invariant would need to be established by static
initialization, and if all interesting invariants could be established that way
then we wouldn't need constructors in the first place. So either you water down
the invariant, or you refrain from calling virtuals in ctors. Even virtuals
which don't touch any member data.

cheers,
Mike

Sean Kelly <sean f4.ca> writes:

In article <db11j9$176k$1 digitaldaemon.com>, Walter says...
"llothar" <llothar_member pathlink.com> wrote in message
news:dauhd9$1uv0$1 digitaldaemon.com...
 Sorry a simple yes/no question.

 Just theoretical evaluating the chance to move my project from eiffel to

d, so i
 would really like to see a "yes" here.

Yes.

D constructors are passed a "fully formed" class object instance, with each
of its fields set to its corresponding default value. This includes the
pointer to the virtual function table pointer (vptr), which is set to the
most derived class' vtbl[].

This is unlike C++, where the fields are garbage, and vptr is set to the
vtbl[] of the constructor's class, rather than the vtbl[] of the most
derived class.

I assume the same is true for the dtor as well?


Sean