Standard ML OCaml Haskell Python Makefile C
Fetching latest commit…
Cannot retrieve the latest commit at this time.

The CakeML project:

CakeML is a verified implementation of a significant subset of Standard ML.

The source and proofs for CakeML are developed in the HOL4 theorem prover. We use the latest development version of HOL4, which we build on PolyML 5.7. Example build instructions can be found in

The master branch contains the latest development version of CakeML. See the version2 or version1 branch for previous versions.

Directory structure

COPYING: CakeML Copyright Notice, License, and Disclaimer.

basis: Contains the beginnings of a standard basis library for CakeML, similar to the standard basis library of SML. This file describes how to install Poly/ML, HOL and CakeML.

candle: Verification of a HOL theorem prover, based on HOL Light (, implemented in CakeML.

characteristic: A verified CakeML adaption of Arthur Charguéraud's "Characteristic Formulae for the Verification of Imperative Programs"

compiler: A verified compiler for CakeML, including:

  • parsing: lexer and PEG parser
  • inference: type inferencer
  • backend: compilation to ASM assembly language
  • targets: code generation to x86, ARM, and more

developers: This directory contains scripts for automating routine tasks, e.g. for running regression tests.

documentation: Work-in-progress documentation regarding the CakeML language.

examples: Examples of verified programs built using CakeML infrastructure.

misc: Auxiliary files providing glue between a standard HOL installation and what we want to use for CakeML development.

semantics: The definition of the CakeML language. The definition is (mostly) expressed in Lem (, but the generated HOL is also included. The directory includes definitions of:

  • the concrete syntax
  • the abstract syntax
  • small step semantics
  • big step semantics (both functional and relational)
  • semantics of FFI calls
  • a type system

translator: A proof-producing translator from HOL functions to CakeML.

tutorial: An extended worked example on using HOL and CakeML to write verified programs, to be presented as a tutorial on CakeML at PLDI and ICFP in 2017.

unverified: Various unverified tools, e.g. tools for converting OCaml to CakeML and an SML version of the CakeML register allocator.