frozen VS pika

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.

I just switched Pika to using significant indentation. This is mostly because of how annoying line continuation is in a ML-style language (so f a b syntax) without significant indentation or required semicolons, but you can read more about the reasons for that decision in this section of the README.

Recently, I've been working on adding garbage collection to Pika. I've successfully written an Immix-based garbage collector that works with the LLVM GC support infrastructure, and I'm currently working on integrating the GC with Pika, or really Durin, the dependently-typed intermediate representation that Pika compiles to. Because types are passed around at runtime, objects of unknown type and size can be stored unboxed in polymorphic data structures; but that makes keeping track of type information for heap allocations somewhat harder, because type information needs to be allocated and constructed at runtime in some cases. It's an interesting design problem, because you want constructing type information to be fast; but the GC will run much more often, so maximizing tracing speed by avoiding e.g. indirection in type information is important; and you also want to construct as much type information as possible at compile time and embed it as constants.

I've been working on adding algebraic effects to Pika during the past month. It's turned out to be harder than I thought it would, but I'm almost done - performing and catching one effect at a time works, and the compilation strategy I'm using now (I reimplemented the whole thing after realizing the strategy I was using wouldn't actually work) should be enough to handle multiple effects at once and also effect polymorphism, I just have to get those working in the elaborator.

After taking a break from Pika, my dependently-typed ML for systems programming, during the month of January, I've started working on it again by getting recursion to work properly. I'm planning on starting to implement algebraic effects next, and an Immix-based garbage collector for boxed values after that. Here's what my current plan for algebraic effects looks like: