Re: What would break if class was merged with struct

On Sunday, 28 May 2017 at 14:30:00 UTC, Ola Fosheim Grøstad wrote: Struct and class is one type in C++. The difference is in the syntax where the grammar does not allow access protection for the struct keyword. So not semantical, but syntactical. I.e. you can just search-and-replace "struct"

Re: What would break if class was merged with struct

On Sunday, 28 May 2017 at 12:31:35 UTC, Iain Buclaw wrote: I said it all in one breath, so you could leave it up to interpretation whether they applauded the fact that there is a separation in semantics, or whether there is no multiple inheritance in D (except via interfaces). When asking

Re: What would break if class was merged with struct

On 28 May 2017 at 13:30, Ola Fosheim Grøstad via Digitalmars-d wrote: > On Sunday, 28 May 2017 at 09:09:39 UTC, Iain Buclaw wrote: >> >> However, for extern(D) classes, there's actually nothing stopping a D >> compiler implementer from making class types more memory

Re: What would break if class was merged with struct

On Sunday, 28 May 2017 at 09:09:39 UTC, Iain Buclaw wrote: However, for extern(D) classes, there's actually nothing stopping a D compiler implementer from making class types more memory efficient, an optimizing compiler could decide to re-arrange class fields as: class Something {

Re: What would break if class was merged with struct

On 27 May 2017 at 20:13, Ola Fosheim Grøstad via Digitalmars-d wrote: > On Saturday, 27 May 2017 at 18:06:11 UTC, Stanislav Blinov wrote: >> >> Perhaps it wouldn't be if we were talking about new language. >> With D, such a change falls out of "some language changes,

Re: What would break if class was merged with struct

On Sunday, 28 May 2017 at 08:24:50 UTC, Iain Buclaw wrote: Strictly speaking, this already is the case. Something sth = new Something (...); all that is really doing is just: struct Something* sth = new Something (...); You just aren't exposed this in the language. Right, but since

Re: What would break if class was merged with struct

On 27 May 2017 at 20:34, Jonathan M Davis via Digitalmars-d wrote: > On Saturday, May 27, 2017 16:37:04 Ola Fosheim Grøstad via Digitalmars-d > wrote: >> > Monitor (i.e. for "synchronized") and >> >> Wasn't this going to be removed? > > There was definitely talk of

Re: What would break if class was merged with struct

On 27 May 2017 at 16:12, Ola Fosheim Grøstad via Digitalmars-d wrote: > I wonder, what would break if all the features of class was merged into > struct? > > Imagine that: > > class Something ... { ... } > > is lowered into: > > struct _class_Something ... {

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 20:24:26 UTC, Moritz Maxeiner wrote: Sure, and the definition requires it. [1] https://dlang.org/spec/abi.html#delegates Please note that an ABI is an implementation specific linkage detail, it cannot be portable so it does not define language semantics.

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 20:24:26 UTC, Moritz Maxeiner wrote: On Saturday, 27 May 2017 at 19:26:50 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 19:01:12 UTC, Moritz Maxeiner wrote: Here, `bar`, takes a (pointer to a) class instance as parameter `foo`. `foo` is a single

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 19:26:50 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 19:01:12 UTC, Moritz Maxeiner wrote: Here, `bar`, takes a (pointer to a) class instance as parameter `foo`. `foo` is a single pointer, i.e. 8 bytes on a 64bit OS, with *no* special semantics.

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 19:01:12 UTC, Moritz Maxeiner wrote: Here, `bar`, takes a (pointer to a) class instance as parameter `foo`. `foo` is a single pointer, i.e. 8 bytes on a 64bit OS, with *no* special semantics. Does the language spec say anything about the size of class references?

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:56:47 UTC, Stanislav Blinov wrote: I've seen this argument from you before, and it's incorrect. Structs may adopt reference semantics if they aggregate pointers, that's true. But they are not themselves reference types. Their representation is laid out inline.

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:42:02 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 18:26:07 UTC, Moritz Maxeiner wrote: mechanism, but you *cannot* use a smart pointer as a replacement for a class instance, because the latter is normal pointer, and the former adds features on

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:44:42 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 18:44:03 UTC, Stanislav Blinov wrote: On Saturday, 27 May 2017 at 18:13:52 UTC, Ola Fosheim Grøstad wrote: Or did we leave behind your original question? No. I am talking about language

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:13:52 UTC, Ola Fosheim Grøstad wrote: Or did we leave behind your original question? No. I am talking about language semantics. Are the semantics for class and struct conflicting or can they be merged? That is the question. I am talking about the language,

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:44:03 UTC, Stanislav Blinov wrote: On Saturday, 27 May 2017 at 18:13:52 UTC, Ola Fosheim Grøstad wrote: Or did we leave behind your original question? No. I am talking about language semantics. Are the semantics for class and struct conflicting or can they be

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:26:07 UTC, Moritz Maxeiner wrote: mechanism, but you *cannot* use a smart pointer as a replacement for a class instance, because the latter is normal pointer, and the former adds features on top of a pointer; they cannot be the same as a matter of definition,

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:33:36 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 18:21:41 UTC, Moritz Maxeiner wrote: Then please don't call them "smart", because that term is specifically reserved for something that adds at least some additional features over a regular pointer

Re: What would break if class was merged with struct

On Saturday, May 27, 2017 16:37:04 Ola Fosheim Grøstad via Digitalmars-d wrote: > > Monitor (i.e. for "synchronized") and > > Wasn't this going to be removed? There was definitely talk of doing it, but it's never actually happened. I don't think that it was actually decided that we would though,

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:21:41 UTC, Moritz Maxeiner wrote: Then please don't call them "smart", because that term is specifically reserved for something that adds at least some additional features over a regular pointer (bounds checking, memory / lifetime management, etc.). "smart

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 17:28:47 UTC, Stanislav Blinov wrote: On Saturday, 27 May 2017 at 17:19:48 UTC, Moritz Maxeiner wrote: On Saturday, 27 May 2017 at 17:02:40 UTC, Ola Fosheim Grøstad wrote: The class reference type should be fixable with a rewrite into templated smart pointers,

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 17:24:14 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 17:19:48 UTC, Moritz Maxeiner wrote: On Saturday, 27 May 2017 at 17:02:40 UTC, Ola Fosheim Grøstad wrote: The class reference type should be fixable with a rewrite into templated smart

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 18:06:11 UTC, Stanislav Blinov wrote: Perhaps it wouldn't be if we were talking about new language. With D, such a change falls out of "some language changes, a bit of automated source updating and a little bit of breakage", and becomes "whole language change, a

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 17:30:49 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 17:22:02 UTC, Stanislav Blinov wrote: But they are incompatible precisely because structs "don't have it". Inheritance for one. Reference semantics for another. A class reference is a pointer in

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 17:22:02 UTC, Stanislav Blinov wrote: But they are incompatible precisely because structs "don't have it". Inheritance for one. Reference semantics for another. A class reference is a pointer in disguise, struct is full layout on the stack. The only way to retain

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 17:19:48 UTC, Moritz Maxeiner wrote: On Saturday, 27 May 2017 at 17:02:40 UTC, Ola Fosheim Grøstad wrote: The class reference type should be fixable with a rewrite into templated smart pointers, so no need for big changes there, I think. Smart pointers impose

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 17:19:48 UTC, Moritz Maxeiner wrote: On Saturday, 27 May 2017 at 17:02:40 UTC, Ola Fosheim Grøstad wrote: The class reference type should be fixable with a rewrite into templated smart pointers, so no need for big changes there, I think. Smart pointers impose

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 17:02:40 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 16:52:17 UTC, Stanislav Blinov wrote: But structs in D have none of that. Neither does C++ if you don't add a virtual function to it, so it would be the same. My question isn't whether structs

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 17:02:40 UTC, Ola Fosheim Grøstad wrote: The class reference type should be fixable with a rewrite into templated smart pointers, so no need for big changes there, I think. Smart pointers impose a specific object lifetime, whereas (D) classes do not. You

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 16:52:17 UTC, Stanislav Blinov wrote: But structs in D have none of that. Neither does C++ if you don't add a virtual function to it, so it would be the same. My question isn't whether structs have it now, but if the concept struct and class could be merged.

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 16:37:04 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 16:31:32 UTC, Stanislav Blinov wrote: There's a lot more difference in D. Classes in D are fat memory chunks storing pointers to ClassInfo (inc. vtable), So are classes with virtual functions in

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 16:31:32 UTC, Stanislav Blinov wrote: There's a lot more difference in D. Classes in D are fat memory chunks storing pointers to ClassInfo (inc. vtable), So are classes with virtual functions in C++, to get RTTI you need to have a virtual member function. I don't

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 16:23:33 UTC, Ola Fosheim Grøstad wrote: On Saturday, 27 May 2017 at 16:04:42 UTC, Stanislav Blinov wrote: It's not "a little bit", it's ABI down the drain, along with a good part of runtime. And we'd lose interfaces and extern(C++). Why would you loose interfaces

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 16:04:42 UTC, Stanislav Blinov wrote: It's not "a little bit", it's ABI down the drain, along with a good part of runtime. And we'd lose interfaces and extern(C++). Why would you loose interfaces and extern(C++)? "struct" and "class" are interchangeable keywords in

Re: What would break if class was merged with struct

On Saturday, 27 May 2017 at 14:12:09 UTC, Ola Fosheim Grøstad wrote: I wonder, what would break if all the features of class was merged into struct? Imagine that: class Something ... { ... } is lowered into: struct _class_Something ... { ... } alias Something =

What would break if class was merged with struct

I wonder, what would break if all the features of class was merged into struct? Imagine that: class Something ... { ... } is lowered into: struct _class_Something ... { ... } alias Something = MagicClassRef!_class_Something; Is it conceivable with some language changes, a bit of