lpil/ante

A safe, easy systems language

Ante

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Ante is a low-level functional language for exploring refinement types, lifetime inference, and other fun features. Here's a quick taste:

type Person = name: string, job: ref string

// Infer that the data referenced via `&` should not be freed inside this function
make_person name =
    Person name &"programmer"

// bob is only used at this scope, so it can be safely freed afterward
bob = make_person "bob"

// unlike ownership systems, aliasing is allowed with lifetime inference
bob_twin = bob
assert (bob.name == bob_twin.name)

In general, ante is low-level (no GC, values aren't boxed by default) while also trying to be as readable as possible by encouraging high-level approaches that can be optimized with low-level details later on.

See the website and language tour for more information.

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Roadmap

• Whitespace-sensitive lexer
• Parser
• Name Resolution
• Full type inference
  • Traits with multiple parameters and limited functional dependencies
  • Compiler option to write inferred types into program source after successful compilation
• LLVM Codegen
• No Garbage Collector
  • Region Inference for refs
  • RAII to allow Rc t or Box t when necessary
• Language Documentation:
  • Article on Ante's use of whitespace for line continuations
  • Article on the sugar for immediately invoked recursive functions (loop/recur)
  • Article on interactions between mut, ref, and passing by reference
  • Article on autoboxing recursive types for polymorphic pointer types
• Refinement Types
• Cranelift backend for faster debug builds
• Incremental compilation metadata
• REPL

Nice to have but not currently required:

• Reasonable automatic C/C++ interop with clang api
• Build system built into standard library
  • Ante should always be able to build itself along with any required libraries, the main question is how should a build system facilitate the more complex tasks of building other languages or running arbitrary programs like yacc/bison.

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Contributing

The compiler is still in a rather early state so any contributors are greatly welcome. Feel free to contribute to either any known issues/improvements (some are listed in the "Quick Tasks" list below) or any standard library functions you think may be useful.

Each file in the codebase is prefixed with a module comment explaining the purpose of the file and any algorithms used. src/main.rs is a good place to start reading.

Make sure any PRs pass the tests in the examples directory. These tests have commands in them which the goldentests library uses to run the ante compiler and check its output for each file against the expected output contained within comments of that file.

Quick Tasks to contribute to

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Community

The best place to follow ante's development is in the #ante channel of the Programming Languages discord: https://discord.gg/4Kjt3ZE. There is also the subreddit at /r/ante which is mainly used for questions about the language rather than development updates.

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Building

Ante currently requires llvm 13.0 while building. If you already have this installed with sources, you may be fine building with cargo build alone. If cargo build complains about not finding any suitable llvm version, the easiest way to build llvm is through llvmenv. In that case, you can build from source using the following:

Linux and Mac

$ cargo install llvmenv
$ llvmenv init
$ llvmenv build-entry -G Makefile -j7 13.0.0
$ llvmenv global 13.0.0
$ LLVM_SYS_130_PREFIX=$(llvmenv prefix)
$ cargo build

If llvmenv prefix defaults to a path with spaces in it, you may get an error during cargo build complaining it cannot find the path to llvm. If this happens, try manually moving the installation in llvmenv prefix to a new directory without spaces, updating LLVM_SYS_130_PREFIX to this new location and re-running cargo build.

Windows

$ cargo install llvmenv
$ llvmenv init
$ llvmenv build-entry -G VisualStudio -j7 13.0.0
$ llvmenv global 12.0.1
$ for /f "tokens=*" %a in ('llvmenv prefix') do (set LLVM_SYS_120_PREFIX=%a)
$ cargo build

You can confirm your current version of llvm by running llvmenv version or llvm-config

If the above steps don't work for you, you can try building llvm from source with cmake. If you're on windows this requires you to have Visual Studio 2017 or later installed already.

$ git clone https://github.com/llvm/llvm-project --branch=release/10.x
$ mkdir llvm-build
$ cd llvm-build
$ cmake ../llvm-project/llvm

At this point, cmake may error that it failed to find z3, or the windows SDK in which case you may need to install them. For the windows SDK, you can install it via the Visual Studio Installer (under Modify -> Individual Components). I used version 10.0.17763.0, though it is likely newer versions will work as well. Rerun the last cmake command to test that everything is installed right. Once this is done, move on to compiling llvm and ante:

$ cmake --build .
$ cmake --build . --target install
$ cd ..
$ set LLVM_SYS_120_PREFIX=/absolute/path/to/llvm-build
$ cargo build