Mathport is a tool for porting Lean3 projects to Lean4. It consists of two (loosely coupled) components:

• "binport", which translates Lean3 .lean files to Lean4 .olean files
• "synport", which best-effort translates Lean3 .lean files to Lean4 .lean files

A full run of mathport (see below) on Lean 3 and mathlib3 takes several hours. We provide artifacts on the github releases page, and separate repositories containing the .lean files and .olean files generated from Lean 3 and from mathlib3.

Please use the repositories https://github.com/leanprover-community/lean3port and https://github.com/leanprover-community/mathlib3port and run lake build to obtain the generated .olean files.

Using these repositories, you can open the synported .lean files in VS Code to see the current state of output.

Alternatively, you can import some or all of the binported .olean files using e.g.

import Mathbin.AlgebraicGeometry.Scheme

#lookup3 algebraic_geometry.Scheme
#check AlgebraicGeometry.Scheme

(Specifying the mathlib3port repository as a Lake dependency in your own project should work to enable import Mathbin.All.)

Update 2022-10-21: The above binport configuration is no longer supported by default. The olean files generated by the nightlies now prioritize using the user specified alignments over type-correctness, so many mathlib theorems will be broken or stubbed. The old behavior can be recovered by setting "skipDefEq": false in the config.json, but you will have to run mathport yourself (see below) rather than downloading the pre-built artifacts created by make port.

The synported .lean files are checked in to these repositories: feel free to commit new versions if you have updated the dependencies in the relevant lakefile and downloaded fresh .lean files using the update.sh <tag> script, where <tag> is a release from https://github.com/leanprover-community/mathport/releases

See the Makefile for usage (it takes several hours to rebuild the mathlib3 port from scratch). Basic usage is make build source predata port.

We provide artifacts for various stages of the build on the releases page of the mathport repository. The script ./download-release.sh nightly-YYYY-MM-DD downloads one of these, after which you can skip the make predata and/or make port steps (you will still need to run make build and make source).

The script ./download-release.sh separately calls download-predata.sh and download-ported.sh. We run CI for predata more frequently.

To port a single file execute mathport as follows (depending on whether you want to port a core or a mathlib file):

./build/bin/mathport config.json Leanbin::init.data.nat.gcd
./build/bin/mathport config.json Mathbin::field_theory.abel_ruffini

The directory Test contains subdirectories importLeanBin and importMathbin, each containing a lakefile.lean that depends on lean3port and mathlib3port, resp.

Mathport also supports a "oneshot" mode, for quick tests. A template is set up in the Oneshot/ directory. See Oneshot/README.md.