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MLton has the following features.

## Portability

- Runs on a variety of platforms.

- AMD64:

- FreeBSD

- Linux (Debian, Red Hat, ...)

- HPPA:

- HPUX (11.00 and above)

- Linux (Debian)

- PowerPC:

- AIX (5.1 and above)

- Darwin (Mac OS X)

- Linux (Debian)

- X86:

- Cygwin/Windows

- Darwin (Mac OS X)

- FreeBSD

- Linux (Debian, Red Hat, ...)

- MinGW/Windows

- NetBSD

- OpenBSD

- Sparc

- Linux (Debian)

- Solaris

## Robustness

- Supports the full SML 97 language as given in The Definition of Standard ML (Revised).
  If there is a program that is valid according to The Definition that is rejected by MLton, or a program that is invalid according to the Definition that is accepted by MLton, it is a bug. For a list of known bugs, see UnresolvedBugs.

- A complete implementation of the Basis Library.
  MLton's implementation matches latest Basis Library specification, and includes a complete implementation of all the required modules, as well as many of the optional modules.

- Generates standalone executables.
  No additional code or libraries are necessary in order to run an executable, except for the standard shared libraries. MLton can also generate statically linked executables.

- Compiles large programs.
  MLton is sufficiently efficient and robust that it can compile large programs, including itself (over 140K lines). The distributed version of MLton was compiled by MLton.

- Support for large amounts of memory (up to 4G on 32-bit systems; more on 64-bit systems).

- Array lengths up to 231 - 1, the largest possible twos-complement 32-bit integer.

- Support for large files, using 64-bit file positions.

## Performance

- Executables have excellent running times.

- Generates small executables.
  MLton takes advantage of whole-program compilation to perform very aggressive dead-code elimination, which often leads to smaller executables than with other SML compilers.

- Native integers, reals, and words.
  In MLton, integers and words are 32 bits and arithmetic does not have any overhead due to tagging or boxing. Also, reals are stored unboxed, avoiding any overhead due to boxing.

- Unboxed native arrays.
  In MLton, an array (or vector) of integers, reals, or words uses the natural C-like representation. This is fast and supports easy exchange of data with C. Monomorphic arrays (and vectors) use the same C-like representations as their polymorphic counterparts.

- Multiple garbage collection strategies.

- Fast arbitrary precision arithmetic (`IntInf`) based on the GnuMP.
  For `IntInf` intensive programs, MLton can be an order of magnitude or more faster than Poly/ML or SML/NJ.

## Tools

- Source-level Profiling of both time and allocation.

- MLLex lexer generator

- MLYacc parser generator

- ML-NLFFIGEN

## Extensions

- A simple and fast C ForeignFunctionInterface that supports calling from SML to C and from C to SML.

- The ML Basis system for programming in the very large, separate delivery of library sources, and more.

- A number of extension libraries that provide useful functionality that cannot be implemented with the Basis Library. See below for an overview and MLtonStructure for details.

- continuations
  MLton supports continuations via `callcc` and `throw`.

- finalization
  MLton supports finalizable values of arbitrary type.

- interval timers
  MLton supports the functionality of the C `setitimer` function.

- random numbers
  MLton has functions similar to the C `rand` and `srand` functions, as well as support for access to `/dev/random` and `/dev/urandom`.

- resource limits
  MLton has functions similar to the C `getrlimit` and `setrlimit` functions.

- resource usage
  MLton supports a subset of the functionality of the C `getrusage` function.

- signal handlers
  MLton supports signal handlers written in SML. Signal handlers run in a separate MLton thread, and have access to the thread that was interrupted by the signal. Signal handlers can be used in conjunction with threads to implement preemptive multitasking.

- size primitive
  MLton includes a primitive that returns the size (in bytes) of any object. This can be useful in understanding the space behavior of a program.

- system logging
  MLton has a complete interface to the C `syslog` function.

- threads
  MLton has support for its own threads, upon which either preemptive or non-preemptive multitasking can be implemented. MLton also has support for Concurrent ML (CML).

- weak pointers
  MLton supports weak pointers, which allow the garbage collector to reclaim objects that it would otherwise be forced to keep. Weak pointers are also used to provide finalization.

- world save and restore
  MLton has a facility for saving the entire state of a computation to a file and restarting it later. This facility can be used for staging and for checkpointing computations. It can even be used from within signal handlers, allowing interrupt driven checkpointing.

Last edited on 2007-08-24 21:51:26 by MatthewFluet.