Interesting link, but if anybody is interested in making real practical use of generics in a C-style language, then it's best to take a look at Zig.
Generics in C without void* or macros – enabled by psychec
11–20 of 74 posts
Re: Generics in C without void* or macros – enabled by psychec
#12No void* or macros, but requires a special compiler frontend.
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Re: Generics in C without void* or macros – enabled by psychec
#13I don't really understand what the point of all this is, and why anyone would consider using this in a real-world application they're developing. There's already a C-like language which lets you write type-safe generic programs: it's called C++! And if for some reason you really want or need to restrict yourself to using C language features (almost) exclusively, you can disable RTTI, exceptions, and use a technique to avoid linking to libstdc++ (or equivalent). It really seems to me that the point of all this is just to reinvent the wheel, but maybe I'm missing something, I only skimmed the paper.
Re: Generics in C without void* or macros – enabled by psychec
#14[deleted]
Re: Generics in C without void* or macros – enabled by psychec
#15Type generic expressions [1] already exist in C11. You can do this without a special compiler front-end if you need it, you would just need to define each variant by hand. These are supported in GCC and Clang with the -std=c11 flag. [1]: http://www.robertgamble.net/2012/01/c11-generic-selections.h...
I developed these ideas a bit further with the use of XX macros, which allow you to make a set of functions generic across some list of types. There can be real performance wins to this over void*: https://abissell.com/2014/01/16/c11s-_generic-keyword-macro-...
Re: Generics in C without void* or macros – enabled by psychec
#16You should never typedef a pointer to an object. That’s common knowledge amongst experienced C developers and an immediate red flag, even for myself normally welcoming of anything built with Haskell.
I'm not an expert C developer but can see some semantic benefits of typedefing a pointer. Is this considered harmful because it hides the fact that you're dealing with a pointer in the first place?
As evidenced by countless examples of somethingPTR-types, it is done regularly. But the main problem is indeed that you hide the pointer.
If you apply qualifiers like const to your type, results might me unexpected.
It might have semantic benefits, but C developers should be trained to ignore all these strange *-symbols anyway.
Re: Generics in C without void* or macros – enabled by psychec
#17I don't really understand what the point of all this is, and why anyone would consider using this in a real-world application they're developing. There's already a C-like language which lets you write type-safe generic programs: it's called C++! And if for some reason you really want or need to restrict yourself to using C language features (almost) exclusively, you can disable RTTI, exceptions, and use a technique t…
I also think it is rather strange for many projects to continue with C, esp for large projects, where c++ offers much conveniences to the programmer. IIRC gcc only recently started allowing c++ in it's source, and I wonder if emacs allows it still in it's source.
Re: Generics in C without void* or macros – enabled by psychec
#18I don't really understand what the point of all this is, and why anyone would consider using this in a real-world application they're developing. There's already a C-like language which lets you write type-safe generic programs: it's called C++! And if for some reason you really want or need to restrict yourself to using C language features (almost) exclusively, you can disable RTTI, exceptions, and use a technique t…
It seems to be aimed at quick prototyping of small programs, relieving you from declaring any structs or datatypes at all. The fields and layout of structs are inferred from the usage. With their frontend, you would be able to implement a type-generic list or a tree only with a few function definitions.
Looking at their example:
_Generic void prepend(_Forall(node_t)** head,
_Forall(value_t) value)
{
node_t* n = malloc(sizeof(node_t));
n->value = value;
n->next = *head;
*head = n;
}
Re: Generics in C without void* or macros – enabled by psychec
#19I don't really understand what the point of all this is, and why anyone would consider using this in a real-world application they're developing. There's already a C-like language which lets you write type-safe generic programs: it's called C++! And if for some reason you really want or need to restrict yourself to using C language features (almost) exclusively, you can disable RTTI, exceptions, and use a technique t…
The problem with C++ is that in addition to generic functionality, it also brings a ton of other baggage that even if you do not use, you still pay for (e.g. personally i really dislike how slow C++ compilers are).
Though TBH i wouldn't use OP's preprocessor either as i think that void* and macros are perfectly fine.
Re: Generics in C without void* or macros – enabled by psychec
#20I don't really understand what the point of all this is, and why anyone would consider using this in a real-world application they're developing. There's already a C-like language which lets you write type-safe generic programs: it's called C++! And if for some reason you really want or need to restrict yourself to using C language features (almost) exclusively, you can disable RTTI, exceptions, and use a technique t…
The problem with C++ is that in addition to generic functionality, it also brings a ton of other baggage that even if you do not use, you still pay for (e.g. personally i really dislike how slow C++ compilers are). Though TBH i wouldn't use OP's preprocessor either as i think that void* and macros are perfectly fine.
Exceptions being one of the notable pieces of baggage...