• Zhenya (9/9) Oct 10 2012 Hi!
• Jonathan M Davis (11/23) Oct 10 2012 const Foo and const(Foo) are the same thing. They both create a const
• Zhenya (3/35) Oct 10 2012 Thank you)

"Zhenya" <zheny list.ru> writes:

Hi!

I thought that this should compile:
class Foo{}

const(Foo) foo = new Foo;// the same that const Foo foo?
foo = new Foo;

but compiler say that foo is const reference and it can't modify 
it.
It is normally?If yes,how can I declare non-const reference to 
const instance of class?

"Jonathan M Davis" <jmdavisProg gmx.com> writes:

On Wednesday, October 10, 2012 19:02:31 Zhenya wrote:
 Hi!
 
 I thought that this should compile:
 class Foo{}
 
 const(Foo) foo = new Foo;// the same that const Foo foo?
 foo = new Foo;
 
 but compiler say that foo is const reference and it can't modify
 it.
 It is normally?If yes,how can I declare non-const reference to
 const instance of class?

const Foo and const(Foo) are the same thing. They both create a const 
reference to const data. This is in contrast to a pointer where const Bar* and 
const(Bar)* are different. With a reference, there is no way to indicate that 
the object is const but not the reference. The type system just doesn't 
support the idea of a class object existing separately from a reference, so 
there's no way to make that distinction.

If you want to have a mutable reference to a const object, then you need a 
wrapper around the reference where the wrapper is mutable but the reference 
isn't. std.typecons.Rebindable does this. It's what you should use.

- Jonathan M Davis

"Zhenya" <zheny list.ru> writes:

On Wednesday, 10 October 2012 at 17:35:48 UTC, Jonathan M Davis 
wrote:
 On Wednesday, October 10, 2012 19:02:31 Zhenya wrote:
 Hi!
 
 I thought that this should compile:
 class Foo{}
 
 const(Foo) foo = new Foo;// the same that const Foo foo?
 foo = new Foo;
 
 but compiler say that foo is const reference and it can't 
 modify
 it.
 It is normally?If yes,how can I declare non-const reference to
 const instance of class?

 const Foo and const(Foo) are the same thing. They both create a 
 const
 reference to const data. This is in contrast to a pointer where 
 const Bar* and
 const(Bar)* are different. With a reference, there is no way to 
 indicate that
 the object is const but not the reference. The type system just 
 doesn't
 support the idea of a class object existing separately from a 
 reference, so
 there's no way to make that distinction.

 If you want to have a mutable reference to a const object, then 
 you need a
 wrapper around the reference where the wrapper is mutable but 
 the reference
 isn't. std.typecons.Rebindable does this. It's what you should 
 use.

 - Jonathan M Davis

Thank you)