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digitalmars.D - mutable

reply Marc =?UTF-8?B?U2Now7x0eg==?= <schuetzm gmx.net> writes:
I've adapted my previous DIP on lazy initialization to make it 
usable for logical immutability, as is useful for reference 
counting, among other things:

http://wiki.dlang.org/DIP89
Feb 21 2016
next sibling parent reply Nick Treleaven <ntrel-pub mybtinternet.com> writes:
On Sunday, 21 February 2016 at 15:03:39 UTC, Marc Schütz wrote:

 I've adapted my previous DIP on lazy initialization to make it 
 usable for logical immutability, as is useful for reference 
 counting, among other things:

 http://wiki.dlang.org/DIP89


BTW the Usage section still uses lazy. I think the RCObject code 
shouldn't use new to construct the struct here:

auto o = new immutable(RCObject);

It probably needs to be on the stack instead.

(I also made a minor edit for formatting/readability, hope that's 
OK).
Feb 21 2016
parent Marc =?UTF-8?B?U2Now7x0eg==?= <schuetzm gmx.net> writes:
On Sunday, 21 February 2016 at 18:19:35 UTC, Nick Treleaven wrote:

 BTW the Usage section still uses lazy. I think the RCObject 
 code shouldn't use new to construct the struct here:

 auto o = new immutable(RCObject);

 It probably needs to be on the stack instead.


Thanks, fixed.


 (I also made a minor edit for formatting/readability, hope 
 that's OK).


Sure :-)
Feb 21 2016
prev sibling next sibling parent Nick Treleaven <ntrel-pub mybtinternet.com> writes:
On Sunday, 21 February 2016 at 15:03:39 UTC, Marc Schütz wrote:

 I've adapted my previous DIP on lazy initialization to make it 
 usable for logical immutability, as is useful for reference 
 counting, among other things:

 http://wiki.dlang.org/DIP89


 From the DIP:


 The second rule ( system) prevents accidental accesses that 
 violate [logical const-ness]


It seems we could use  mutable as a method attribute instead of 
 trusted const. The advantage would be that code is still checked 
for  safety. Requiring it still helps to prevent unintentional 
mutation and remind the programmer about correct logical const 
encapsulation. I realise  trusted has more impact but really here 
this use isn't related to memory safety, (or is it)?
Feb 21 2016
prev sibling parent reply Guillaume Chatelet <chatelet.guillaume gmail.com> writes:
 static make() {


The return type is missing for the make() function:
Feb 22 2016
parent reply Nick Treleaven <ntrel-pub mybtinternet.com> writes:
On Monday, 22 February 2016 at 17:28:03 UTC, Guillaume Chatelet 
wrote:

 static make() {


 The return type is missing for the make() function:


I'm pretty sure static here works just like 'static auto'. In D I 
think you can use storage classes (and even attributes) to imply 
auto:

const foo(){return 5;}

assert(foo() == 5);
Feb 22 2016
next sibling parent Guillaume Chatelet <chatelet.guillaume gmail.com> writes:
On Monday, 22 February 2016 at 18:03:03 UTC, Nick Treleaven wrote:

 On Monday, 22 February 2016 at 17:28:03 UTC, Guillaume Chatelet 
 wrote:

 static make() {


 The return type is missing for the make() function:


 I'm pretty sure static here works just like 'static auto'. In D 
 I think you can use storage classes (and even attributes) to 
 imply auto:

 const foo(){return 5;}

 assert(foo() == 5);


Ha right indeed it's probably going to work. It was just a bit 
surprising.
Feb 23 2016
prev sibling parent Timon Gehr <timon.gehr gmx.ch> writes:
On 22.02.2016 19:03, Nick Treleaven wrote:

 On Monday, 22 February 2016 at 17:28:03 UTC, Guillaume Chatelet wrote:

 static make() {


 The return type is missing for the make() function:


 I'm pretty sure static here works just like 'static auto'. In D I think
 you can use storage classes (and even attributes) to imply auto:

 const foo(){return 5;}

 assert(foo() == 5);


It does not really "imply auto". 'auto' means nothing in this context, 
it's just a crutch for  the parser. The return type is deduced if it is 
left out. In order to leave it out, you need to provide some storage 
class. 'auto' is just one possibility.
Feb 23 2016