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digitalmars.D.learn - C++ vs D aggregates

reply Dejan Lekic <dejan.lekic gmail.com> writes:
I recently stumbled on this thread: http://stackoverflow.com/
questions/5666321/what-is-assignment-via-curly-braces-called-and-can-it-
be-controlled

The important part is this:

-------- 8< --------- begin ---------
The Standard says in section §8.5.1/1,

An aggregate is an array or a class (clause 9) with no user-declared 
constructors (12.1), no private or protected non-static data members 
(clause 11), no base classes (clause 10), and no virtual functions (10.3).

And then it says in §8.5.1/2 that,

When an aggregate is initialized the initializer can contain an 
initializer-clause consisting of a brace-enclosed, comma-separated list 
of initializer-clauses for the members of the aggregate, written in 
increasing subscript or member order. If the aggregate contains 
subaggregates, this rule applies recursively to the members of the 
subaggregate.
-------- >8 --------- end ---------

Do D2 aggregates behave the same, or are there notable differences?
Dec 03 2011
next sibling parent Don <nospam nospam.com> writes:
On 03.12.2011 20:14, Dejan Lekic wrote:

 I recently stumbled on this thread: http://stackoverflow.com/
 questions/5666321/what-is-assignment-via-curly-braces-called-and-can-it-
 be-controlled

 The important part is this:

 -------- 8<  --------- begin ---------
 The Standard says in section §8.5.1/1,

 An aggregate is an array or a class (clause 9) with no user-declared
 constructors (12.1), no private or protected non-static data members
 (clause 11), no base classes (clause 10), and no virtual functions (10.3).

 And then it says in §8.5.1/2 that,

 When an aggregate is initialized the initializer can contain an
 initializer-clause consisting of a brace-enclosed, comma-separated list
 of initializer-clauses for the members of the aggregate, written in
 increasing subscript or member order. If the aggregate contains
 subaggregates, this rule applies recursively to the members of the
 subaggregate.
 -------->8 --------- end ---------

 Do D2 aggregates behave the same, or are there notable differences?



Yes, struct static initializers are the same in D as in C++.
Differences are:
* D also has struct literals, which can be used in contexts other than 
initialization;
* There are no static initializers for classes. (D's classes are never 
'aggregates' in the C++ sense);
* Static initializers for unions are currently very buggy in DMD.
Dec 03 2011
prev sibling next sibling parent reply Kagamin <spam here.lot> writes:
Dejan Lekic Wrote:


 Do D2 aggregates behave the same, or are there notable differences?



D restricts usage to static initializers only, C++ doesn't have this limitation.
Dec 04 2011
next sibling parent Timon Gehr <timon.gehr gmx.ch> writes:
On 12/04/2011 12:00 PM, Kagamin wrote:

 Dejan Lekic Wrote:


 Do D2 aggregates behave the same, or are there notable differences?



 D restricts usage to static initializers only, C++ doesn't have this
limitation.



This works:

struct S{int x;}

void main(){
     int a;
     S x = {a};
}

What does not?
Dec 04 2011
prev sibling parent "Dejan Lekic" <dejan.lekic gmail.com> writes:
 What does not?
Dec 07 2011
prev sibling parent =?UTF-8?B?QWxleCBSw7hubmUgUGV0ZXJzZW4=?= <xtzgzorex gmail.com> writes:
On 03-12-2011 20:14, Dejan Lekic wrote:

 I recently stumbled on this thread: http://stackoverflow.com/
 questions/5666321/what-is-assignment-via-curly-braces-called-and-can-it-
 be-controlled

 The important part is this:

 -------- 8<  --------- begin ---------
 The Standard says in section §8.5.1/1,

 An aggregate is an array or a class (clause 9) with no user-declared
 constructors (12.1), no private or protected non-static data members
 (clause 11), no base classes (clause 10), and no virtual functions (10.3).

 And then it says in §8.5.1/2 that,

 When an aggregate is initialized the initializer can contain an
 initializer-clause consisting of a brace-enclosed, comma-separated list
 of initializer-clauses for the members of the aggregate, written in
 increasing subscript or member order. If the aggregate contains
 subaggregates, this rule applies recursively to the members of the
 subaggregate.
 -------->8 --------- end ---------

 Do D2 aggregates behave the same, or are there notable differences?



Does TDPL have a chapter on this? I think my searching skills may be 
failing me.

- Alex
Dec 04 2011