Lambda Buffers

Introduction

LambdaBuffers is a schema language (similar to ProtoBuffers, ADL, ASN.1, JSON Schema, etc.) and associated code generation toolkit. The goal of this project is to provide developers tools to define algebraic data types in a language-agnostic format such that shared data types can be declared in one place while maintaining compatibility across a plethora of supported languages.

Users may refer to the comparison matrix for an in-depth comparison of LambdaBuffers' features against the feature-set of other popular schema-languages.

At a glance, you may wish to choose LambdaBuffers instead of one of its competitors if your project requires:

1. Parameterized Data Types (aka. type functions): Unlike ProtoBuffers or JSON Schema, LambdaBuffers allows users to define algebraic data types which take type variable arguments. If your project's domain is most accurately represented by parameterized data types, LamdaBuffers may be a good choice for your needs.

2. Opaque Types: Almost every competing schema language provides users a fixed set of builtin or primitive types, which are handled in a special manner by the code generation and cannot be extended. LambdaBuffers, by contrast, allows users to add their own builtin types and extend the existing code generation framework to handle those builtins in a manner intended by the users. There are no special primitive types in LambdaBuffers; a user-defined primitive type is defined in exactly the same way (i.e. as an opaque type) as a LambdaBuffers "builtin".

3. Typeclass Support: While nearly every schema language supports generating type definitions in supported target languages, to our knowledge no schema language supports generating commonly used functions that operate on those types. Unlike other schema languages, LambdaBuffers supports code generation for typeclass instances (or the equivalent in languages that lack support for typeclasses) to reduce the amount of boilerplate required to productively make use of the generated types. While LambdaBuffers is still a work-in-progress, we expect that, upon completion, an extensive test suite will provide a high degree of assurance that the instances/methods generated by the LamdaBuffers code generator behave identically.

Documentation

• Design,
• Compiler,
• Codegen,
• Comparison matrix,
• User feedback

Getting started

Installing Nix

This repository relies heavily on the Nix Package Manager for both development and package distribution.

To install run the following command:

sh <(curl -L https://nixos.org/nix/install) --daemon

and follow the instructions.

$ nix --version
nix (Nix) 2.8.0

NOTE: The repository should work with Nix version greater or equal to 2.8.0.

Make sure to enable Nix Flakes and IFD by editing either ~/.config/nix/nix.conf or /etc/nix/nix.conf on your machine and add the following configuration entries:

experimental-features = nix-command flakes
allow-import-from-derivation = true

Optionally, to improve build speed, it is possible to set up a binary caches maintained by IOHK and Plutonomicon by setting additional configuration entries:

substituters = https://cache.nixos.org https://iohk.cachix.org https://cache.iog.io https://public-plutonomicon.cachix.org
trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= iohk.cachix.org-1:DpRUyj7h7V830dp/i6Nti+NEO2/nhblbov/8MW7Rqoo= public-plutonomicon.cachix.org-1:3AKJMhCLn32gri1drGuaZmFrmnue+KkKrhhubQk/CWc=

Building and development

To facilitate seamlessly moving between directories and associated Nix development shells we use direnv and nix-direnv:

To install both using nixpkgs:

nix profile install nixpkgs#direnv
nix profile install nixpkgs#nix-direnv

Your shell and editors should pick up on the .envrc files in different directories and prepare the environment accordingly. Use direnv allow to enable the direnv environment and direnv reload to reload it when necessary.

Additionally, throughout the repository one can use:

$ pre-commit run --all
cabal-fmt............................................(no files to check)Skipped
fourmolu.................................................................Passed
hlint....................................................................Passed
markdownlint.............................................................Passed
nix-linter...............................................................Passed
nixpkgs-fmt..............................................................Passed
shellcheck...........................................(no files to check)Skipped
typos....................................................................Passed

To run all the code quality tooling specified in the pre-commit-check config file