[SUGGESTION] change to unique and shared in cpp2 namespace

[farmerpiki]

They cause issues when being used with c++ modules ... yes, I know we're not supposed to talk about them yet... but they are supposed to be supported as first class citizens eventually.

Solutions include:

• renaming it as a namespace and removing the const on the functions and changing how they are accessed
• naming the structs instead and declaring the functions inside them static
• leaving everything dynamic and making them extern and available in a separately compiled file
• actually creating a module with their definitions
• leave a single name for each way to do things... right now for unique.new we have 3 names: new, cpp2_new and unique.new, maybe a single way for each would be simpler (new and shared_new?)
• have a way to annotate new(@shared new) ... the annotation may allow us to later choose which arena to allocate gc.new from

I'm just trying to pick on what the best path forward is, maybe it's too soon for the discusion and I understand that but some of these solutions change syntax a bit

[farmerpiki]

it's clang 16 with libstdc++ and headers from gcc 12.3 ... and I have the change from static to inline for nonesuch imported, should I try to produce minimal code to reproduce the problem?

[farmerpiki]

I tried to minimize the example as much as possible still needs 2 modules, but at least I got it relatively short, I left both the cpp2 files and generated files, also the build.log file and added a build.sh to see the commands I used to build this.
https://github.com/farmerpiki/cpp2-issue

the relevant part from the build.log file
In module 'personal' imported from /home/g-zu/projects/proofoffailure/public.pure.cpp:9:
/home/g-zu/projects/cppfront/include/cpp2util.h:519:3: error: definition with same mangled name '_ZN4cpp26uniqueE' as another definition
} unique;
^
/home/g-zu/projects/cppfront/include/cpp2util.h:519:3: note: previous definition is here
} unique;
^

P.S. I don't know, this might very well be a compiler issue with current modules, but since we plan to support them and the issue is present in one of the major compilers...

[JohelEGP]

shared isn't mentioned in the output.
So the reason for me not noticing this issue is because I used neither of the names unique or shared.
You did use unique, which is why you noticed.

[farmerpiki]

I didn't use shared but I imagine the same thing would happen since it's declared the same

[farmerpiki]

This still happens with inline!?
It also happens with shared, I checked

[hsutter]

OK, reopening... my impression was that changing them to inline would resolve the issue but evidently not, thanks for the information. It seemed like inline was an improvement anyway so I went ahead and did it, and I'm open to other improvements.

I'm not yet working on enabling full support for modules, until modules support appears and stabilizes in the major compilers. But I'm still happy to entertain suggestions for changes that would help this issue, especially if they would be an improvement anyway like inline on those static objects.

Thanks!

[farmerpiki]

Any idea which would be closer to an acceptable solution? I tried and the namespace version seems to work... though it involves one extra character in total...
I can try as many options as you wish in order to make it work if you give me ideas.
Willing to put in the work for this, unique pointers are especially dear to my heart and I want to have this work, trying to write a personal project with as much as possible pure cpp2 syntax.

[farmerpiki]

Oh, so nothing changed cause they're in the cpp2 namespace?
Would there be a chance we can include a way to declare the destructor type in the syntax of new? For the cases when we use libraries which allocate their own pointers and have special functionality to free them.

[JohelEGP]

Seems like make_unique doesn't permit specifying the deleter.

[farmerpiki]

would you be opposed to just moving the stuff from instantiated structs into functions

template
[[nodiscard]] auto cpp2_new(auto &&...args) -> std::unique_ptr {
return std::make_unique(CPP2_FORWARD(args)...);
}

template
[[nodiscard]] auto cpp2_shared_new(auto &&...args) -> std::unique_ptr {
return std::make_shared(CPP2_FORWARD(args)...);
}

these just work, without inline, static or other tricks
also we could have them as unique_new and shared_new instead of unique.new and shared.new and everything else would work the same I guess.

I realize this is a breaking change, I could also move them to a separate file just for your patches JohelEGP and build them as a separate module.