[](https://input-output-hk.github.io/cardano-ledger/)

This repository contains the formal specifications, executable models, and implementations of the Cardano Ledger.

The documents are built in our CI and can be readily accessed using the following links:

Other Documents:

• Non-integer calculations specification: details on the parts of the Shelley specification that use real numbers.
• Stake pool ranking specification: details for a robust stake pool ranking mechanism.
• Explanation of the small-step-semantics framework: a guide to the notation and style used by our ledger rules.

In addition, there is a formalization of the Ledger Specification in Isabelle/HOL which can be found here.

Some user documentation is published on Read the Docs

Haddock code documentation of the latest master branch is available here.

The directory structure of this repository is as follows:

• byron
  • ledger
    • formal-spec
    • executable-spec
    • implementation
  • chain
    • formal-spec
    • executable-spec
  • cddl
• shelley
  • design-spec
  • formal-spec
  • implementation
  • tests
  • cddl
• Timelocks and Multi-Assets
  • formal-spec
  • implementation
  • tests
• Smart Contracts
  • formal-spec
  • implementation
  • tests
• Libraries

It is recommended to use nix for building everything in this repository. Haskell files can be built with cabal inside of a nix shell.

When using nix it is recommended that you setup the cache, so that it can reuse built artifacts, reducing the compilation times dramatically:

If you are using NixOS add the snippet below to your /etc/nixos/configuration.nix:

nix.settings = {
  experimental-features = [ "nix-command" "flakes" ];
  substituters = [
    "https://cache.nixos.org"
    "https://cache.iog.io"
  ];
  trusted-public-keys = [
    "hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="
  ];
};

If you are using the nix package manager next to another operating system put the following in /etc/nix/nix.conf:

experimental-features = nix-command flakes
substituters        = https://cache.iog.io https://cache.nixos.org/
trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=

When using nix the documents and Haskell code can be readily built by running:

nix build .#specs

The LaTeX documents will be placed inside a directory named result, e.g.:

result/byron-ledger.pdf
result/shelley-delegation.pdf
result/non-integer-calculations.pdf
result/small-step-semantics.pdf
result/shelley-ledger.pdf
result/byron-blockchain.pdf

Change to the latex directory where the latex document is (e.g. eras/shelley/formal-spec for the ledger specification corresponding to the Shelley release, or eras/byron/ledger/formal-spec for the ledger specification corresponding to the Byron release). Then, build the latex document by running:

cd <myLaTexDir>
nix develop --command make

For a continuous compilation of the LaTeX file run:

cd <myLaTexDir>
nix develop --command make watch

Before running tests with cabal test, the CARDANO_MAINNET_MIRROR environment variable should be set to the path to mainnet epochs on your local storage. Note that this is only needed for the Byron tests.

Issues can be filed in the GitHub Issue tracker.

However, note that this is pre-release software, so we will not usually be providing support.

See CONTRIBUTING.