# MLton/mlton

The MLton repository

Repository: https://github.com/MLton/mlton
Canonical: https://ross.abutalabs.com/products/mlton
Homepage: http://mlton.org
Language: Standard ML
License: NOASSERTION
License Family: other
Topics: mlton, standard-ml, sml, functional-programming, compiler
Last push: 2026-09-02T00:06:14+00:00

## Health v2 (maintenance only)
Score: 68/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 100, release rhythm 8, longevity 100
- inputs: {"age_days": 4926, "days_push": 1, "days_rel": 611, "gap_med": null, "n_releases_24m": 1}
- flags: no_license, no_readme
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1091, forks 138 (observed 2026-09-03T02:15:06.532205+00:00)

## What it is
MLton is a whole-program optimizing compiler for the Standard ML (SML97) programming language that generates small, fast standalone executables. It includes a complete Basis Library implementation, language extensions, a C FFI, lexer and parser generators, and a profiler.

## Use cases
- compile Standard ML programs to fast native executables
- build statically linked SML binaries
- port SML/NJ code to MLton
- generate lexers and parsers for SML with mllex and mlyacc
- profile SML programs
- call C libraries from Standard ML via FFI
- do arbitrary-precision arithmetic in SML with GMP-backed IntInf

## When to choose
- you need the fastest runtime performance for Standard ML code
- you want standalone or statically linked executables with no runtime dependencies
- you need full SML97 compliance and a complete Basis Library implementation
- you want aggressive dead-code elimination and small binaries

## When to avoid
- you need fast incremental compilation or interactive REPL-style development
- compile-time memory usage or whole-program compile times are a concern for very large projects
- you need a different language than Standard ML

## Facets
- artifact type: cli-tool
- maturity: active
- function: compiler, programming-language, parser, cli, developer-tools
- domain: compilers, programming-languages, developer-tools
- platform: windows, bsd, cross-platform, cli
- tags: standard-ml, sml, sml97, whole-program-optimization, functional-programming, mllex, mlyacc, profiler, ffi, gmp, command-line, linux, macos

## Member repositories
- MLton/mlton (main) score 68

## Provenance
- Observed fields: from GitHub, fetched 2026-09-03T02:15:06.532205+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:49:20.576457+00:00, confidence not recorded.
  - homepage: http://mlton.org (fetched 2026-08-29T12:51:40.375705+00:00, sha 32bc72b0fe85)
  - site_page: http://mlton.org/Features (fetched 2026-08-29T12:51:40.378474+00:00, sha dfcb9d5d041d)
  - site_page: http://mlton.org/Documentation (fetched 2026-08-29T12:51:40.380664+00:00, sha e97cb373b9f2)
  - site_page: http://mlton.org/FAQ (fetched 2026-08-29T12:51:40.382879+00:00, sha 00bbbeaff8b9)
- Data as of 2026-08-30T08:39:29.467469+00:00.