Time to kill T() as (sometimes) working T.init alias ?

[Dan]

On Monday, 10 December 2012 at 11:03:28 UTC, Walter Bright wrote:
>
> Have you ever written a struct that requires a deep copy?
>
> I have, and I always wound up redoing it so the deep copy was 
> unnecessary.

How do you get around it? Let's say you have an address book 
structure that organizes addresses by email. Without a postblit 
or some deep copy, duplicating means sharing. When I see this, I 
think - I better add a postblit in case address books get copied. 
How would you approach it to not need deep copy? For something as 
simple as this would you introduce COW?

Thanks,
Dan

---------------------------
module phone.phone;

import std.stdio;

struct Address {
   string street;
   string zipCode;
   string state;
   string country;
}

struct AddressBook {
   alias Address[string] EmailAddressMap;

   void addAddress(string email, Address address) {
     _emailAddressMap[email] = address;
   }

   private {
     EmailAddressMap _emailAddressMap;
   }
}


unittest {
   AddressBook office;
   office.addAddress("foo at aol.com", Address("201 Foo Dr", "99999", 
"Fl", "USA"));
   AddressBook copy = office;
   copy.addAddress("goo at aol.com", Address("202 Foo Dr", "99999", 
"Fl", "USA"));
   writeln(office);
   writeln(copy);
}