Kore is the "core" part of the K framework.
In short, we need a formal semantics of K. In K, users can define formal syntax and semantics of programming languages as K definitions, and automatically obtain parsers, interpreters, compilers, and various verification tools for their languages. Therefore K is a language-independent framework.
Thanks to years of research in matching logic and reachability logic, we know that all K does can be nicely formalized as logic reasoning in matching logic. To give K a formal semantics, we only need to formally specify the underlying matching logic theories with which K does reasoning. In practice, these underlying theories are complex and often infinite, and it is tricky to specify infinite theories without a carefully designed formal specification language. And Kore is such a language.
The docs directory contains a collection of documents that describe the mathematical foundation of Kore and a BNF grammar that defines the syntax of Kore language. See /docs/introduction.md for an overview of the components of Kore.
kore project is an implementation in Haskell of a Kore parser and symbolic execution engine,
for use with the K Framework as a backend.
stack build kore # or cabal build kore
You may pass
stack build or
cabal build in order to
disable compiler optimizations and make build faster at the cost of slower runtime.
make all # builds all binaries
Developers will require all the dependencies listed above, in addition to the requirements and recommendations below.
For integration testing, we require:
- GNU make
- The K Framework frontend (its version should be the one stated in /deps/k_release)
- Python 3.x with the
You can install/have access to K by either:
- using kup
- using a pre-built binary (see the releases page in the K repository)
- if you use Nix, see the section below
- using the
Dockerfileto run the integration tests inside a container
- or by just building K from source
docker.sh to run commands inside the container:
./docker/build.sh # run once when dependencies change ./docker/run.sh make all # build the backend ./docker/run.sh make test # run all tests ./docker/run.sh make -C test/imp test # run all tests in test/imp
For setting up a development environment, we recommend:
- direnv to make the project's tools available in shells and editors.
- ghcup or Nix for managing required Haskell tooling
- hlint for compliance with project guidelines.
ghcup provides a straightforward way of installing the language server, if you prefer to use Nix please refer to the relevant resources on how to set up your Nix environment to build the server. Note: HLS has to be built with the project's GHC version.
Prequisite: build the project with either Stack or Cabal.
Instructions on integrating with VSCode:
- Install the Haskell extension
- Go to
Extension Settingsand pick
- (Optional) Manually set the GHCup executable path
- (Extra) Set
fourmolufor correct formatting
To build and run nix based packages at RV, please follow these instructions to set up nix:
We are using nix flakes in all our repos. What this means at a high level is that some of the commands for building packages look a bit different.
To set up nix flakes you will need to install
nix 2.4 or higher.If you are on a standard Linux distribution, such as Ubuntu, first install nix
and then enable flakes by editing either
/etc/nix/nix.conf and adding:
experimental-features = nix-command flakes
Note that if this is your first time using Nix you will have to manually create one of the
This is needed to expose the Nix 2.0 CLI and flakes support that are hidden behind feature-flags. (If you are on a different system like nixOS, see instructions for enabling flakes here: https://nixos.wiki/wiki/Flakes)
By default, Nix will build any project and its transitive dependencies from source, which can take a very long time. We therefore need to set up some binary caches to speed up the build process. First, install cachix
nix profile install github:cachix/cachix/v1.1
and then add the
k-framework cachix cache
cachix use k-framework
Next, we need to set up the cache for our haskell infrastructure, by adding the following sections to
/etc/nix/nix.conf or, if you are a trusted user,
~/.config/nix/nix.conf (if you don't know what a "trusted user" is, you probably want to do the former):
trusted-public-keys = ... hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= substituters = ... https://cache.iog.io
i.e. if the file was originally
substituters = https://cache.nixos.org trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
it will now read
substituters = https://cache.nixos.org https://cache.iog.io trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ=
Make sure that the file wasn't overwritten, if it was add the
The CI requires all Haskell files to be formatted via fourmolu.
If using VSCode, please refer to the language server section above. If not, the easiest way to do this locally is to run
nix run .#format
This will format all the haskell files in the given folder and all sub-folders. You can
cd into a particular subfolder and run the command there, or if you only want to format a specific file, you can provide it as an argument to the above command:
nix run .#format Foo.hs
We provide a development nix shell with a suitable development environment and
a binary cache at runtimeverification.cachix.org. The development can be launched via
nix develop and then calling
When one of the package description files (
kore-rpc-types.cabal) changes, or when upgrading to a newer
stack resolver, the dependencies need to be consolidated to avoid accidental breakage from incompatible up-stream updates. We use a
cabal.project.freeze file to pin the dependencies to what the current
stack resolver is using.
scripts/freeze-cabal-to-stack-resolver.sh should do most of that work (the existing
freeze file must be removed before running it), and
scripts/check-cabal-stack-sync.sh checks the result. Some manual adjustments will still be necessary for the
nix builds in CI and locally to work.
In addition, any GHC or resolver upgrades must double-check the
index-state values in the
Haskell-backend provides an integration shell for running integration tests, which compile the K framework (of a specified version) against your current version of haskell backend and brings K into scope of your current shell.
The integration shell is part of the
k repository, but invoked from the local tree, adding additional tools (see
haskell-backend dependency must be overridden to use the
haskell-backend dependency from the current checked-out tree, and the
k version will usually be the one from
To use this nix shell, execute
me@somewhere:haskell-backend$ nix develop \ github:runtimeverification/k/v$(cat deps/k_release)#kore-integration-tests \ --override-input haskell-backend . --update-input haskell-backend ... ...(nix output) integration-shell:me@somewhere:haskell-backend$
(This will take some time the first time you run it for a specific K framework version...)
A specific commit or version tag of the K framework github repository can be used instead of
Running this command will add all of the K binaries like
kast into the
PATH of your current shell. This is not permanent and will only persist in your current shell window until you exit the active nix shell).
integration-shell:me@somewhere:haskell-backend$ make -C test/issue-3344 test ... ...(make output) integration-shell:me@somewhere:haskell-backend$ exit me@somewhere:haskell-backend$