frozen VS xvm

I found this extension that implements "frozen" versions of some C++ containers, but I was wondering if there is a good solution available in the standard library.

A library exists that can produce constexpr hash table based containers.

I use the Frozen library for that. Since the conversions should be known at compile time you can make constexpr hash tables for lookups.

The constexpr dependency of note here is frozen.

In C++, a drop-in replacement for your DSA can provide significant improvements over the standard library. Particularly the standard unordered_map class can be improved by 50% to 100% (e.g. https://github.com/greg7mdp/parallel-hashmap, or for static maps https://github.com/serge-sans-paille/frozen). Of course, recognize that creating a DS/A from scratch is an entire project, and you shouldn't roll your own for an independent codebase.

Technologies (for curious folks): C++17, SFML, Entt, Frozen, Protobuf, spdlog, GoogleTest, GoogleBenchmark, CMake and Dear ImGui for debug purpose.

In the language, I added anonymous array literals. I did some cleanup in the compiler and updated to LLVM 12 from 10 (which was pretty trivial, surprisingly). I also added frozen, a C++ perfect-hashing library, as a dependency to speed up the lookup of keywords in my lexer. The library exploits C++’s constexpr features to generate a perfect hash at compile-time without any separate build step, which is great, and it also provides a drop-in replacement for std::unordered_map that uses the hash.

This is where I plug Frozen :-] https://github.com/serge-sans-paille/frozen

I’ve no idea how hard it is to implement, but return type polymorphism would be nice. Especially returning different things based on the constexpress of the result. And then add Frozen eqivalents of associative containers to the STL, so that, for example constexpr auto set = std::make_set(...) would be frozen::set, and auto set = std::make_set(...) would be std::set.

In which case, I believe the answer your question would be yes: the frozen map.

Have a look at the ecstasy library for the language definitions of these types.

2) Funky interfaces: This is an Ecstasy interface that declares abstract static members (e.g. functions), which can then be implemented on any class and overridden on any sub-class, such that they can be invoked by type (instead of this), and virtually resolved (late bound at runtime) based on the type known at compile time. The best known example, of course, is Hashable, because it has to guarantee that a type implements both equals() and hashCode() on the same class, and the implementation is tied to the type, and not to the this. (C# added a similar feature last year in version 11.)

I'm just going to warn you in advance that invocation is one of the hardest things in the compiler to make easy. In other words, the nicer your language's "developer experience" is around invocation, the more hell you're going to have to go through to get there. The AST nodes for Name( (NameExpression) and Invoke( (InvocationExpression) alone are 7kloc in the Ecstasy implementation, for example -- but the result is well worth it.

Ecstasy uses message passing automatically behind the scenes for asynchronous calls, but the message passing isn't visible at the language level (i.e. there is no "message object" or something like that visible). Basically, all Ecstasy code is executing on a fiber inside a service, and services are all running concurrently, so from any service realm to any service realm, the communication is by message.

Regarding Ecstasy, we did not set out to build a new language; we actually set out to solve a real world problem. Specifically, we wanted to be able to dramatically improve the density of workloads in data centers, by at least two orders of magnitude in the case of lightly used applications. Our initial goal was to create a runtime design that would support 10,000 stateful application instances on a single server. Let's call it the "a10k" problem 🤣 ... a tribute to the c10k problem from 1999. We refer to our goal as "zero carbon compute", i.e. we want to push the power and hardware cost for an application to as close to zero as possible; you can't reach zero, but you can get close. If we succeed, we will help reduce the electricity used in data centers over the next few decades by a significant percentage.

Generally, left to right, one character at a time. If you’re looking for example code, here’s a simple hand-built lexer.

Parts of Ecstasy are now implemented in Ecstasy. Here's the Lexer, for example.

Ecstasy

Ecstasy and the xvm were designed assuming an adaptive runtime compiler (similar in concept to the Hotspot compiler for Java), but not necessarily using a JIT.

A Future reference has the various capabilities that you'd imagine, taking lambdas for thenDo(), whenComplete(), etc. The reference, in the above example, is a local variable, so you just obtain it using the C-style & operator: