= http://mlton.org[MLton]

ifdef::env-github[]
image:https://github.com/MLton/mlton/actions/workflows/ci.yml/badge.svg[CI, link = https://github.com/MLton/mlton/actions/workflows/ci.yml]
endif::[]

****
MLton is a whole-program optimizing compiler for the Standard{nbsp}ML
programming language.  MLton generates small executables with
excellent runtime performance, utilizing untagged and unboxed native
integers, reals, and words, unboxed native arrays, fast
arbitrary-precision arithmetic based on GMP, and multiple code
generation and garbage collection strategies.  In addition, MLton
provides a feature rich Standard{nbsp}ML programming environment, with
full support for SML97 as given in The Definition of Standard{nbsp}ML
(Revised), a number of useful language extensions, a complete
implementation of the Standard ML Basis Library, various useful
libraries, a simple and fast C foreign function interface, the ML
Basis system for programming with source libraries, and tools such as
a lexer generator, a parser generator, and a profiler.
****


== Features

 * Robustness.

   - Supports the full SML{nbsp}97 language as given in The Definition of Standard{nbsp}ML (Revised).
   - A complete implementation of the http://sml-family.org/Basis/[Basis Library].
   - Generates standalone executables.
   - Compiles large programs.
   - Support for large amounts of memory (up to 4G on 32-bit systems;
     more on 64-bit systems).
   - Support for large array lengths (up to 2^31^ - 1 on 32-bit systems;
     up to 2^63^-1 on 64-bit systems).
   - Support for large files, using 64-bit file positions.

 * Performance.

   - Executables have excellent runtime performance.
   - Generates small executables.
   - Untagged and unboxed native integers, reals, and words.
   - Unboxed native arrays.
   - Multiple garbage collection strategies.
   - Fast arbitrary-precision arithmetic based on https://gmplib.org[GMP].

 * Tools.

   - Source-level http://mlton.org/Profiling[profiling] for both time and allocation.
   - MLLex lexer generator.
   - MLYacc parser generator.
   - MLNLFFIGEN foreign-function-interface generator.

 * Extensions.

   - The http://mlton.org/MLBasis[ML Basis system] for programming with source libraries.
   - A number of useful http://mlton.org/SuccessorML[language extensions].
   - A simple and fast http://mlton.org/ForeignFunctionInterface[C FFI] that supports calling from SML to C and from C to SML.
   - Libraries for http://mlton.org/MLtonWeak[weak pointers] and http://mlton.org/MLtonFinalizable[finalization], http://mlton.org/MLtonThread[threads], http://mlton.org/MLtonCont[continuations], http://mlton.org/MLtonItimer[interval timers] and http://mlton.org/MLtonSignal[signal handlers], http://mlton.org/MLtonWorld[world save and restore], and http://mlton.org/MLtonStructure[more].

 * Portability.

   - Runs on a wide variety of platforms.


== Build and Install (from source)

=== Requirements

==== Software

 * http://gcc.gnu.org/[GCC] or http://clang.llvm.org[Clang] (The C compiler must support `-std=gnu11`.)
 * http://gmplib.org[GMP] (GNU Multiple Precision arithmetic library)
 * http://savannah.gnu.org/projects/make[GNU Make]
 * http://www.gnu.org/software/bash/[GNU Bash]
 * binutils (`ar`, `ranlib`, `strip`, ...)
 * miscellaneous Unix utilities (`diff`, `find`, `grep`, `gzip`, `patch`, `sed`, `tar`, ...)
 * Standard{nbsp}ML compiler to bootstrap:
   - http://mlton.org[MLton] (`mlton`) recommended.  Pre-built binary packages for MLton can be installed via an OS package manager or (for select platforms) obtained from `http://mlton.org`.
   - http://www.smlnj.org[SML/NJ] (`sml`) supported, but not recommended.
   - https://polyml.org[Poly/ML] (`polyc`) supported, but not recommended.
   - https://elsman.com/mlkit[MLKit] (`mlkit`) supported, but not recommended.
 * (optional, for documentation only) https://ctan.org/tex/[TeX], http://asciidoctor.org/[AsciiDoctor], http://rouge.jneen.net/[Rouge], http://www.graphicsmagick.org/[GraphicsMagick] or https://www.imagemagick.org/[ImageMagick], ...

==== Hardware

 * &ge; 1GB RAM (for 32-bit platforms) or &ge; 2GB RAM (for 64-bit platforms)

=== Build Instructions

On typical platforms, building MLton requires no configuration and can be
accomplished via:

[source,shell]
----
$ make all
----

A small set of `Makefile` variables can be used to customize the build:

 * `CC`: Specify C compiler.  Can be used for alternative tools (e.g.,
   `CC=clang` or `CC=gcc-7`).
 * `WITH_GMP_DIR`, `WITH_GMP_INC_DIR`, `WITH_GMP_LIB_DIR`: Specify GMP include
   and library paths, if not on default search paths.  (If `WITH_GMP_DIR` is
   set, then `WITH_GMP_INC_DIR` defaults to `$(WITH_GMP_DIR)/include` and
   `WITH_GMP_LIB_DIR` defaults to `$(WITH_GMP_DIR)/lib`.)
 * `MLTON_RUNTIME_ARGS`, `MLTON_COMPILE_ARGS`: Specify runtime and compile
   arguments given to (the to-be-built) `mlton` when compiling distributed
   executables ((self-compiled) `mlton`, `mllex`, `mlyacc`, `mlprof`, and
   `mlnlffigen`). Can be used for testing (e.g., `MLTON_COMPILE_ARGS="-codegen
   c"`) or for downstream packaging.
 * `OLD_MLTON_RUNTIME_ARGS`, `OLD_MLTON_COMPILE_ARGS`: Specify runtime and
   compile arguments given to "old" `mlton` when compiling "new" `mlton`. Can be
   used to work around bugs in "old" `mlton` when compiling "new" `mlton`.

For example:

[source,shell]
----
$ make CC=clang WITH_GMP_DIR=/opt/gmp MLTON_COMPILE_ARGS="-codegen c" all
----

The build artifacts are located under `./build`.  The just-built `mlton` can be
executed via `./build/bin/mlton`.

Building documentation can be accomplished via:

[source,shell]
----
$ make docs
----

=== Install Instructions

On typical platforms, installing MLton (after performing `make all` and,
optionally, `make docs`) to `/usr/local` can be accomplished via:

[source,shell]
----
$ make install
----

A small set of `Makefile` variables can be used to customize the installation:

 * `PREFIX`: Specify the installation prefix.

For example:

[source,shell]
----
$ make PREFIX=/opt/mlton install
----


== Install (from binary package)

=== Requirements

==== Software

 * http://gcc.gnu.org/[GCC] or http://clang.llvm.org[Clang] (The C compiler must support `-std=gnu11`.)
 * http://gmplib.org[GMP] (GNU Multiple Precision arithmetic library)
 * http://savannah.gnu.org/projects/make[GNU Make]
 * miscellaneous Unix utilities (`bzip2`, `gzip`, `sed`, `tar`, ...)

=== Binary Package

A `.tgz` or `.tbz` binary package can be extracted at any location, yielding
`README.adoc` (this file), `CHANGELOG.adoc`, `LICENSE`, `Makefile`, `bin/`,
`lib/`, and `share/`.  The compiler and tools can be executed in-place (e.g.,
`./bin/mlton`).

A small set of `Makefile` variables can be used to customize the binary package
via `make update`:

 * `CC`: Specify C compiler.  Can be used for alternative tools (e.g.,
   `CC=clang` or `CC=gcc-7`).
 * `WITH_GMP_DIR`, `WITH_GMP_INC_DIR`, `WITH_GMP_LIB_DIR`: Specify GMP include
   and library paths, if not on default search paths.  (If `WITH_GMP_DIR` is
   set, then `WITH_GMP_INC_DIR` defaults to `$(WITH_GMP_DIR)/include` and
   `WITH_GMP_LIB_DIR` defaults to `$(WITH_GMP_DIR)/lib`.)

For example:

[source,shell]
----
$ make CC=clang WITH_GMP_DIR=/opt/gmp update
----

=== Install Instructions

On typical platforms, installing MLton (after optionally performing
`make update`) to `/usr/local` can be accomplished via:

[source,shell]
----
$ make install
----

A small set of `Makefile` variables can be used to customize the installation:

 * `PREFIX`: Specify the installation prefix.

For example:

[source,shell]
----
$ make PREFIX=/opt/mlton install
----


== Resources

 * `http://mlton.org`
 * Development
   - `https://github.com/MLton/mlton`
   - https://github.com/MLton/mlton/pulls[pull requests]
   - https://github.com/MLton/mlton/issues[issue tracker]
 * Mailing lists
   - `MLton-devel@mlton.org` -- MLton developers
     (https://sourceforge.net/mailarchive/forum.php?forum_name=mlton-devel[archive],
     https://lists.sourceforge.net/lists/listinfo/mlton-devel[subscribe])
   - `MLton-user@mlton.org` -- MLton user community
     (https://sourceforge.net/mailarchive/forum.php?forum_name=mlton-user[archive],
     https://lists.sourceforge.net/lists/listinfo/mlton-user[subscribe])


== Support and Contributing

To report bugs or suggest new features, use the
https://github.com/MLton/mlton/issues[issue tracker] or ask on the
mailto:mlton-user@mlton.org[mailing list].

https://github.com/MLton/mlton/pulls[Pull requests] with bug fixes or
changes are welcome.
