Standard ML of New Jersey

Standard ML of New Jersey (abbreviated SML/NJ) is a compiler for the Standard ML '97 programming language with associated libraries, tools, and documentation. SML/NJ is free, open source software.

What's New

• [2025-12-22] Release 2025.3 of the development version is available. See the README for details.
  
• [2025-11-04] Version 110.99.9 is released. This release is primarily a bug-fix release. See the README for details. Note: we currently do not have a Windows MSI file for this release, but hope to have one soon.
  
• [2025-07-29] Release 2025.2 of the development version is available. See the README for details.
  
• [2025-04-30] We have refreshed the 32-bit binfiles and installers for 110.99.8 to address a 32-bit-specific issue ( Issue #356).
• [2025-04-25] Version 110.99.8 is released. This release is a bug-fix release; there are no new features. See the README for details.
  
• [2025-02-14] Release 2025.1 of the development version is available. This release is the first to provide native support for Apple Silicon (i.e., Arm64) on macOS. See the README for details.
  
• [2025-01-17] Version 110.99.7.1 is released. This patch release fixes a serious bug in 110.99.7. See the README for details.
  
• [2025-01-06] The installer packages for 110.99.7 are now available.
  
• [2024-12-28] Version 110.99.7 is released. Thie end-of-year release has a small number of bug fixes and changes. The installer packages for macOS and Windows have not yet been built.
  
• [2024-10-25] Version 110.99.6.1 is released. This patch release fixes a serious bug in 110.99.6. See the README for details.
  
• [2024-09-18] Version 110.99.6 is released. This version is primarily a bugfix release with some additional improvements. See the README for details.
  
• [2024-07-07] Release 2024.2 of the development version is available. The main change in this release is that the LLVM code generator library has been moved to a submodule.
  
• [2024-05-17] Release 2024.1 of the development version is available. This release incorporats the bug fixes and other improvements from the legacy Version 110.99.5. See the README for details.
  
• [2024-03-14] Version 110.99.5 is released. This version is primarily a bugfix release with some additional improvements. See the README for details.
  
• [2023-12-10] Release 2023.1 of the development version is available. This release fixed issues with running the development version on Linux and recent versions of macOS (Ventura and Sonoma), as well as incorporating the bug fixes from the legacy Version 110.99.4. See the README for details.
  
• [2023-08-01] Version 110.99.4 is released. This version is primarily a bugfix release, but it does include a small number of enhancements as well as support for macOS 14 (Sonoma). See the README for details.
  
• [2022-09-28] The smlnj-gforge server has been shut down. The previous contents have been archived and, in many cases, migrated to the SML/NJ GitHub project.
  
• [2022-08-25] Version 2022.1 is released. This version provides a baseline set of boot files for the new GitHub repository. It also includes the bug fixes from Version 110.99.3. See the README for details.
  
• [2022-07-27] Version 110.99.3 is released. This version is primarily a bugfix release, but it does include a small number of enhancements as well as support for macOS 13 (Ventura). See the README for details.
  
• [2022-07-15] We have taken the first step toward migrating SMLNJ to GitHub. The source repository for the "legacy" branch (i.e., 110.99.x) is now a GitHub project at https://github.com/smlnj/legacy. We have also migrated our bug database to GitHub issues (see below for details).
  
• [2021-12-31] Version 2021.1 is released. This version is viewed as an unstable beta release. It only supports 64-bit AMD64 (aka x86-64) Unix systems (e.g., Linux and macOS). The major change is that we have switched from using MLRISC to LLVM for our code generator (see our recent IFL paper for details). The README has more details about this version.
  
• [2021-09-22] Version 110.99.2 is released. The main purpose of this patch release is to support installing and running SML/NJ on macOS 12 (Monterey). The release also contains a few bug fixes; see the README for details.
  
• [2021-04-12] Version 110.99.1 is released. The main purpose of this patch release is to support installing and running SML/NJ on M1 Macs under the Rosetta2 translator. The release also contains a couple of bug fixes; see the README for details.
  
• Older news

Future Plans

There are currently two versions of SML/NJ. For most uses, we recommend the legacy version (e.g., 110.99.9). The development version is still evolving, but it can be used for day-to-day work.

Support for 64-bit architectures

The latest version (110.99.9) supports 64-bit executables on macOS and Linux.

Downloads

• The latest release is 110.99.9; we believe that this version is stable.

• Previous versions are also available through our release history page. A history of the changes to the system is also available.

• Signed installers for macOS are available, which install the system in /usr/local/smlnj.

  • smlnj-x86-110.99.9.pkg (32 bit)
  • smlnj-amd64-110.99.9.pkg (64 bit)

  Note that to install SML/NJ on macOS 10.15 Catalina, you will have to right-click on the installer package, which should open up a dialog box. Click on the Open button to run the installer.

Git access

Background

• What is SML?
• What is SML '97?
• What is SML/NJ?

Documentation and Literature

• Books
• Tutorials
• SML/NJ User's Guide
• SML'97 Basis Library
• SML/NJ Library documentation
• SML/NJ FAQ (Frequently Asked Questions)
• Top Level Environment Comparison
• Special features of SML/NJ
• Compilation Manager (CM)
• ML Language Processing Tools (ml-ulex and ml-antl)
• ML-Lex
• ML-Yacc
• Concurrent ML
• eXene
• SML/NJ-C foreign function interface
• SML'97 Conversion Guide
• Compiler notes

Reporting Bugs

As of July 2022, we are using GitHub issues to track bug reports and feature requests. We have migrated the existing bug database from our previous bug-tracking system to issues.

• Submit a bug report for the legacy version of SML/NJ (e.g., Version 110.99.9).
• Submit a bug report for the development version of SML/NJ (e.g., Version 2025.3).
• Submit a feature request.

Note that to submit a bug, you will need a GitHub account.

Links

• Pointers to programming resources (libraries, tools, example code), projects using SML/NJ, other SML implementations, related compiler research work, and miscellaneous SML links. The programming resources links will soon move to a separate page of their own.

People

• Picture of current cast of people involved in the project.

This project is based upon work supported in part by the National Science Foundation under Grant No. CNS-0454136.

Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).