Yatima is a Lean 4 compiler backend targeting the the Lurk language for recursive zkSNARKs, enabling zero-knowledge proofs of Lean 4 execution. Additionally, Yatima has its own Lean 4 implementation of a kernel for the Lean 4 core language, which can be compiled to Lurk to allow zero-knowledge proofs of Lean 4 typechecking. By verifying a zero knowledge proof that a Lean 4 declaration has passed the typechecker, one can verify that the declaration is type-safe without re-running the typechecker.

Yatima also implements nameless content-addressing for Lean 4, allowing each expression, declaration and environment to receive unique hash identifiers, independent of computationally-irrelevant naming (such as the names of definitions and local variables).

Run lake run setup, which will build the yatima binary and ask you where to place it. You can choose a directory that's already in your path, for example.

Running the setup script will also compile the Yatima typechecker and store it in the FS, under the $HOME/.yatima directory.

The subcommands planned to be available for the yatima CLI are:

• Main commands
  • ca: content-addresses Lean 4 code to Yatima IR
  • prove: generates Lurk code for typechecking a content-addressed declaration
• Auxiliary commands
  • tc: typechecks Yatima IR
  • gen: generates Lurk code from Lean 4 code
  • pin: edits the TypecheckM.lean file with the hashes for primitive operations and allowed axioms
  • gentc: compiles the Yatima typechecker to Lurk
• Network
  • ipfs put: sends Yatima IR to IPFS
  • ipfs get: retrieves Yatima IR from IPFS

Don't hesitate to call yatima --help for more information.

Constraints:

• The ca subcommand must be triggered from within a Lean project that uses Lake
• The Lean 4 code to be content-addressed must use the same toolchain as the one used to compile the yatima binary. To see the needed toolchain, call yatima --version and check the content before the pipe |
• To compile a Lean 4 file that imports others, the imported olean files must be available