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Subject: Comp.Lang.ML FAQ [Monthly Posting]

This article was archived around: Mon, 10 Oct 2005 23:51:49 +0000 (UTC)

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Archive-name: meta-lang-faq Last-modified: Oct 10, 2005
COMP.LANG.ML Frequently Asked Questions and Answers (compiled by Dave Berry, Greg Morrisett and Rowan Davies) (maintained by Leaf Petersen) Please send corrections, additions, or comments regarding this list to comp-lang-ml-request@cs.cmu.edu. Changes since last posting: - Added entry on Alice/ML (Andreas Rossberg) Contents: --------- 1. What is ML? 2. Where is ML discussed? a. Comp.Lang.ML b. SML-LIST c. CAML-LIST 3. What implementations of ML are available? a. quick summary (by machine/OS) b. Standard ML of New Jersey (SML/NJ) c. sml2c d. Caml Light e. Objective Caml f. Bigloo g. Camlot h. Moscow ML i. ML Kit j. Edinburgh k. MicroML l. Poly/ML m. Poplog ML n. MLWorks o. MLJ p. MLton q. HaMLet 4. Unsupported SML/NJ Ports a. OS/2 b. NEXTSTEP c. SVR4 5. Where can I find documentation/information on ML? a. The Definition b. Textbooks c. Information on the Internet 6. Where can I find ML library code? a. The Standard ML ('97) Basis Library b. The Edinburgh SML Library c. The SML/NJ Library d. SML_TK e. Caml-light libraries f. The Qwertz Toolbox (for AI) 7. Theorem Provers and ML 8. Miscellaneous Questions a. How do I write the Y combinator in SML? b. Where can I find an X-windows interface to SML? c. How do I call a C function from SML/NJ? d. Where can I find an emacs mode for SML? e. What is the value restriction? f. What is the difference between OCaml and Standard ML? -------------------------------------------------------------------------- 0. Where can I find the latest copy of this FAQ? This document can be retrieved via anonymous ftp from ftp://pop.cs.cmu.edu/usr/rowan/sml-archive/faq.txt or from rtfm.mit.edu. There is an HTTP version with active links at http://www.cis.ohio-state.edu/hypertext/faq/usenet/meta-lang-faq/faq.html -------------------------------------------------------------------------- 1. What is ML? ML (which stands for Meta-Language) is a family of advanced programming languages with [usually] functional control structures, strict semantics, a strict polymorphic type system, and parametrized modules. It includes Standard ML, Lazy ML, CAML, CAML Light, and various research languages. Implementations are available on many platforms, including PCs, mainframes, most models of workstation, multi-processors and supercomputers. ML has many thousands of users, is taught at many universities (and is the first programming language taught at some). -------------------------------------------------------------------------- 2. Where is ML discussed? COMP.LANG.ML ------------ comp.lang.ml is a moderated usenet newsgroup. The topics for discussion include but are not limited to: * general ML enquiries or discussion * general interpretation of the definition of Standard ML * applications and use of ML * announcements of general interest (e.g. compiler releases) * discussion of semantics including sematics of extensions based on ML * discussion about library structure and content * tool development * comparison/contrast with other languages * implementation issues, techniques and algorithms including extensions based on ML Requests should be sent to: comp-lang-ml@cs.cmu.edu Administrative mail should be sent to: comp-lang-ml-request@cs.cmu.edu Messages sent to the newsgroup are archived at CMU. The archives can be retrieved by anonymous ftp from internet sites. Messages are archived on a year-to-year basis. Previous years' messages are compressed using the Unix "compress" command. The current year's messages are not compressed. ftp pop.cs.cmu.edu username: anonymous password: <username>@<site> binary cd /usr/rowan/sml-archive get sml-archive.<year>.Z quit zcat sml-archive.<year>.Z (Pop's IP address is Individual messages can also be accessed in the directories /usr/rowan/mh-sml-archive/<year>-sml. SML-LIST -------- The SML-LIST is a mailing list that exists for people who cannot (or do not want to) read the Usenet COMP.LANG.ML newsgroup. Messages are crossposted from COMP.LANG.ML to the SML-LIST and vice-versa. You should ask to join the SML-LIST _only if_ you cannot (or do not want to) read the Usenet COMP.LANG.ML newsgroup. To send a message to the SML-LIST distribution, address it to: sml-list@cs.cmu.edu (sites not connected to the Internet may need additional routing.) Administrative mail such as requests to add or remove names from the distribution list should be addressed to sml-list-request@cs.cmu.edu CAML-LIST --------- The Caml language, a dialect of ML, is discussed on the Caml mailing list. To send mail to the Caml mailing list, address it to: caml-list@inria.fr Administrative mail should be addressed to: caml-list-request@inria.fr ALT.LANG.ML ----------- No longer used. -------------------------------------------------------------------------- 3. What implementations of ML are available and where can I find them? Quick Summary: System full SML? contact Platforms ------ --------- ------------ ------------------------------ SML/NJ yes sml-nj@research.bell-labs.com SML'97 http://cm.bell-labs.com/cm/cs/what/smlnj Alpha - OSF/1 3.2, DUX 4.0 Mips - Irix 4.0.x, 5.x, 6.x x86 - Linux, Solaris, FreeBSD, NetBSD, Windows95, WindowsNT Sparc - SunOS, Solaris RS/6000 - AIX PowerPC - AIX HPPA - HPUX 10 sml2c yes 32-bit Unix machines (C code) http://www.funet.fi/pub/languages/ml/sml2c/ Caml Light coreish caml-light@inria.fr Unix, Mac, PC 80386, ftp ftp.inria.fr (bytecode) Objective own caml-light@inria.fr Unix and Windows NT/95 Caml modules ftp ftp.inria.fr (bytecode) Alpha, Sparc, x86, Mips, HPPA, Power (native code) Bigloo coreish Manuel.Serrano@inria.fr. Unix (compiles caml-light ftp ftp.inria.fr to native code) Camlot coreish Regis.Cridlig@ens.fr Any 32-bit (compiles ftp ftp.inria.fr caml-light to C) Moscow ML yes sestoft@dina.kvl.dk SML'97 http://www.dina.kvl.dk/~sestoft/mosml.html Intel- Windows,OS/2,Linux,FreeBSD Alpha - DUX Sparc - Solaris,SunOS HP9000 - UX 9,UX 10 SGI MIPS - IRIX 5 Mac(68k and PPC) - MacOS,MkLinux, MacOS X Kit yes ftp ftp.diku.dk (Requires another SML compiler ftp ftp.dcs.ed.ac.uk to build binaries) Edinburgh core ftp.dcs.ed.ac.uk 32-bit machines (bytecode) ftp.informatik.uni-muenchen.de PC 80386SX+, Amiga MicroML core Olof.Johansson@cs.umu.se PC 8086+ (bytecode) ftp ftp.cs.umu.se Poly/ML SML 97 http://www.polyml.org Intel - Linux, Windows Sparc - Solaris Mac - MacOS X PoplogML yes isl@isl.co.uk Sparc/Solaris, Intel/Solaris, Intel/Linux, PowerPC/AIX, Alpha/DUX, Intel/Windows MLWorks No longer available MLJ core+ mlj@dcs.ed.ac.uk Unix and Windows NT/95 SML'97 Alpha, Sparc, x86 http://www.dcs.ed.ac.uk/~mlj/ (Compiles to JVM) MLton yes MLton@mlton.org x86 Linux, FreeBSD, Cygwin SML'97 http://www.mlton.org HaMLet yes http://www.ps.uni-sb.de/hamlet/ N/A SML.NET yes http://www.cl.cam.ac.uk/Research/TSG/SMLNET/ (Targets the Common Language Runtime) Alice/ML N/A http://www.ps.uni-sb.de/alice/ x86, PPC Details: Standard ML of New Jersey ------------------------ Standard ML of New Jersey (SML/NJ) was developed jointly at Bell Laboratories, Princeton University, and recently Yale University. The SML/NJ distribution includes CM (a separate compilation manager), ML-Yacc, ML-Lex, ML-Burg, the SML/NJ Library, Concurrent ML, eXene (a multithreaded X-windows toolkit), and the SML/NJ-C interface library. The software is available with source code under a very liberal license. Version 110 of SML/NJ (released in February 1998), is largely compliant with the new SML '97 Definition, including the new Basis library. Version 110 runs on the following machine/os configurations: Alpha OSF/1 3.2, Digital Unix 4.0 Mips Irix 4.0.x, Irix 5.x, Irix 6.x x86 Linux, Solaris, FreeBSD, NetBSD, Windows95, WindowsNT Sparc SunOS, Solaris RS/6000 AIX (also PowerPC) HPPA HPUX 10 For the time being, Macintosh users will have to stick with the previous release, Version 0.93. New ports to MacOS and Rhapsody on PowerPC are planned, and there may also be support for BeOS on PowerPC and Intel. The SML/NJ Version 110 software distribution is available at: Bell Labs: ftp://ftp.research.bell-labs.com/dist/smlnj/release/110/ Stanford: ftp://rodin.stanford.edu/pub/smlnj/release/110/ DIKU: ftp://ftp.diku.dk/pub/smlnj/release/110/ Cambridge: ftp://ftp.cl.cam.ac.uk/MIRRORED/smlnj/release/110/ or through the SML/NJ web site at: http://cm.bell-labs.com/cm/cs/what/smlnj This web site also has extensive online documentation and links to related sites. Another important link is the documentation for the SML '97 Basis, which can be found at: http://SML.sourceforge.net/Basis/ SML2C ----- sml2c is a Standard ML to C compiler. It is based on an old version of SML/NJ from 1992 and shares its front-end and most of the runtime system. sml2c is a batch compiler and compiles only module-level declarations. It does not support SML/NJ style debugging and profiling. sml2c is easily portable and has been ported to IBM RT, Decstation 3100, Decstation 5000, Omron Luna 88k, sun-3, sun-4 and a 486-based machine (running Mach). The generated code is highly portable and makes very few assumptions about the target machine or the C compilers available on the target machine. The runtime system, which it shares with the SML/NJ has several machine and operating system dependencies. sml2c has eliminated some of these dependencies by using portable schemes for garbage collection and for freezing and restarting programs. sml2c is available by anonymous ftp from ftp.cs.cmu.edu ( Log in as anonymous, send username@node as password. The distribution can be found in /afs/cs/project/mess/research/sml2c/ftp. The local ftp software will allow you to change directory only to /afs/cs/project/mess/research/sml2c/ftp. The README file in this directory describes the files in the distribution. The size of the uncompressed distribution is about 12 Meg. CAML LIGHT ---------- Caml Light is a portable, bytecode interpreter for CAML, a dialect of ML. Some features of Caml Light include separate compilation, streams and stream parsers, ability to link to C code, and a fairly rich library. The implementation has low memory requirements, compiles quickly and generates compact executables. The Caml Light system comprises a batch compiler, a toplevel-based interactive compiler, tools for building libraries and toplevel systems, a replay debugger, and a hypertext-based module browser. Caml Light runs on most modern Unix machines, including Sun Sparcstations (under SunOS 4.1 and Solaris 2), Decstations 3000 (Alpha) and 5000 (Mips), and PCs under Linux, but many more machines have been reported to work. It is also available for the Macintosh (as a "fat binary" that runs native on PowerMacs) and the PC under MS Windows and MSDOS. The current version is 0.73, released in January 1997. It is available by anonymous ftp from: host: ftp.inria.fr ( directory: lang/caml-light Summary of the files: README.cl More detailed summary cl73unix.tar.gz Unix version (source code) cl73macbin.sea.bin Binaries for the Macintosh version cl73win.exe Binaries for MS Windows and MSDOS cl73refman.* Reference manual, in various formats cl73tutorial.* Tutorial, in various formats cl73macdoc.sea.bin On-line documentation for the Macintosh version cl73macsrc.sea.bin Source code for the Macintosh version More information on Caml Light is available on the Web at: http://pauillac.inria.fr/caml The implementors can be contacted at caml-light@inria.fr. General questions and comments of interest to the Caml community should be sent to caml-list@inria.fr, the Caml mailing list. (see question 2 above for details.) OBJECTIVE CAML -------------- Objective Caml (formerly known as Caml Special Light) is a complete reimplementation of Caml Light that adds a complete class-based object-oriented system and a powerful module system in the style of Standard ML. The object system is statically type-checked (no "message not understood" run-time errors) and performs ML-style type reconstruction (no type declarations for function parameters). This is arguably the first publically available object-oriented language featuring ML-style type reconstruction. The module system is based on the notion of manifest types / translucent sums; it supports Modula-style separate compilation, and fully transparent higher-order functors. Objective Caml comprises two compilers: a bytecode compiler in the style of Caml Light (but up to twice as fast), and a high-performance native code compiler for the following platforms: Alpha processors: DecStation 3000 under OSF1 (a.k.a. Digital Unix) Sparc processors: Sun Sparcstation under SunOS 4.1, Solaris 2, NetBSD Intel 486 and Pentium processors: PCs under Linux, NextStep, FreeBSD, Windows 95 and Windows NT Mips processors: DecStation 3100 and 5000 under Ultrix 4 HP PA-RISC processors: HP 9000/700 under NextStep (no HPUX yet) PowerPC processors: IBM RS6000 and PowerPC workstations under AIX 3.2 The native-code compiler delivers excellent performance (better than Standard ML of New Jersey 1.08 on our tests), while retaining the moderate memory requirements of the bytecode compiler. The source distribution (for Unix machines only) is available by anonymous FTP on ftp.inria.fr, directory lang/caml-light. More information on Objective Caml is available on the World Wide Web, at: http://pauillac.inria.fr/ocaml/ Bug reports and technical questions should be directed to caml-light@inria.fr. For general questions and comments, use the Caml mailing list caml-list@inria.fr (to subscribe: caml-list-request@inria.fr). BIGLOO ------ Bigloo is an optimizing Scheme-to-C and Caml-to-C compiler that produces native machine code from Caml sources. Compatibility with the bytecoded implementation of Caml Light is almost perfect. Performance of generated code is on a par with that of New Jersey ML. Bigloo is also one of the most efficient Scheme compilers available. Bigloo runs on the following Unix platforms: Decstations 3000 and 5000, Sparcstations, PCs under Linux, HP PA 730 and Sony News R3000. Bigloo is being developed by Manuel Serrano (Manuel.Serrano@inria.fr). Available from: ftp://ftp.inria.fr/lang/caml-light/bcl*.tar.gz. CAMLOT ----- Camlot is the stand alone Caml Light to C compiler. It then uses a standard C compiler to produce an executable machine code file. The compiler itself is mostly written in Caml Light and the runtime system is written in standard C, hence Camlot is easy to port to almost any 32-bit platform. The performance of the resulting code is quite good, often ten times faster than the bytecode original implementation of Caml Light. The distribution has been tested on the following platforms: Sun Sparcstation DecStation 3100 HP 9000/710 i386/486 Linux The distribution is avaiable at: ftp://ftp.inria.fr/lang/caml-light/camlot0.64a.tar.gz MOSCOW ML --------- Moscow ML provides a light-weight implementation of full Standard ML, including Modules and some extensions. Moscow ML is based on the Caml Light bytecode system, which gives fast compilation and modest storage consumption. Moscow ML 2.00 properties: * Supports the full SML'97, including Modules (structures, signatures, and functors), thanks to Claudio Russo * Also provides several extensions to the SML Modules language: - higher-order functors: functors may be defined within structures and functors - first-class modules: structures and functors may be packed and then handled as Core language values, which may then be unpacked as structures or functors again - recursive modules: signatures and structures may be recursively defined * Implements Standard ML, as revised 1997 (value polymorphism, default overloading resolution, new types) * Remains backwards compatible with previous releases of Moscow ML * Implements most of the new Standard ML Basis Library, including the most common input/output facilities in TextIO and BinIO * Built-in help function * Interactive top-level as well as separate (batch) compilation * Can produce compact stand-alone executables * Supports quotations and antiquotations, useful for metaprogramming * Dynamic linking of external functions (Linux/x86 and Linux/Alpha, Solaris, Digital Unix, HP-UX, MacOS, Win'95/98/NT/2000) * Interface to Boutell's library for making PNG images (structure Gdimage) * Interface to the PostgreSQL database server (structure Postgres) * Interface to the MySQL database server (structure Mysql) * Interface to POSIX 1003.2 regular expressions (structure Regex) * Interface to sockets (structure Socket) * Interface to GNU gdbm persistent hashtables (structures Gdbm, Polygdbm) * Facilities for fast functional generation of HTML code (structure Msp) * Facilities for using CGI (structure Mosmlcgi and Mosmlcookie) * Registration of ML and C functions for callbacks (structure Callback) SUPPORTED PLATFORMS Intel x86-based PCs running Windows'95, '98, 'NT, and '2000, OS/2, Linux or FreeBSD; DEC Alpha running Linux or Digital Unix; Sun Sparc running Solaris or SunOS; HP9000 running HP/UX 9 or HP/UX 10; SGI MIPS running IRIX 5; Macintosh (68k and PPC) running MacOS (thanks to Doug Currie) or MkLinux, MacOS X. AUTHORS * Sergei Romanenko (roman@keldysh.ru), Moscow, Russia * Claudio V. Russo (Claudio.Russo@cl.cam.ac.uk), Cambridge, UK * Peter Sestoft (sestoft@dina.kvl.dk), Copenhagen, Denmark AVAILABILITY * The Moscow ML homepage is http://www.dina.kvl.dk/~sestoft/mosml.html * Moscow ML library documentation http://www.dina.kvl.dk/~sestoft/mosmllib/ * The Linux executables and documentation are in ftp://ftp.dina.kvl.dk/pub/mosml/linux-mos20bin.tar.gz * The Unix source files and documentation are in ftp://ftp.dina.kvl.dk/pub/mosml/mos20src.tar.gz * The MS Windows 95/98/NT executables and documentation are in ftp://ftp.dina.kvl.dk/pub/mosml/win32-mos20bin.zip * The MacOS (68k and PPC) executables and docs and source diffs are in ftp://ftp.dina.kvl.dk/pub/mosml/MacMoscowML20installer.hqx * The MS Windows 95/98/NT/2000 source files are in ftp://ftp.dina.kvl.dk/pub/mosml/win32-mos20src.zip Postscript and PDF versions of the documentation included with the binaries can be found in ftp://ftp.dina.kvl.dk/pub/mosml/doc/ Peter Sestoft (sestoft@dina.kvl.dk) 2000-08-03 The ML Kit ---------- Two versions of the ML Kit are available from DIKU: (a) The ML Kit (Version 1, 1993) (b) The ML Kit with Regions (1997) Both are described in more detail at the DIKU ML Kit web site: http://www.diku.dk/research-groups/topps/activities/mlkit.html ML Kit Version 1 ---------------- Version 1 of the ML Kit is a straight translation of the 1990 Definition of Standard ML into a collection of Standard ML modules. For example, every inference rule in the Definition is translated into a small piece of Standard ML code which implements it. The translation has been done with as little originality as possible - even variable conventions from the Definition are carried straight over to the Kit. If you are primarily interested in executing Standard ML programs efficiently, the ML Kit is not the system for you! (It uses a lot of space and is very slow.) The Kit is intended as a tool box for those people in the programming language community who may want a self-contained parser or type checker for full Standard ML but do not want to understand the clever bits of a high-performance compiler. We have tried to write simple code and module interfaces; we have not paid any attention to efficiency. The documentation is around 100 pages long and is provided with the Kit. It explains how to build, run, read and modify the Kit. It also describes how typing of flexible records and overloading are handled in the Kit. The ML Kit is written by Nick Rothwell, David N. Turner, Mads Tofte and Lars Birkedal at Edinburgh and Copenhagen Universities. The ML Kit with Regions (aka Version 2) --------------------------------------- Version 2 builds on Version 1, but is expanded into a real compiler. Inefficient data structures and algorithms in the system have been replaced by more efficient ones. The ML Kit with Regions is intended for the development of stand-alone applications which must be reliable, fast and space efficient. The main feature of the ML Kit with Regions is that it uses a stack of regions for memory management rather than traditional garbage collection techniques; this has several important consequences: Compile-Time Garbage Collection: All memory allocation directives (both allocation and de-allocation) are inferred by the compiler, which uses a number of novel program analyses concerning lifetimes and storage layout. There is no pointer-tracing garbage collection at runtime; Memory Safety: Safety of de-allocation of memory is ensured by the compiler; Static detection of space leaks; Region Resetting: It is possible to give explicit directives about resetting of regions in cases where the static analyses are too conservative; such directives are checked by the compiler; Region Profiling: The system includes a graphical region profiler, which helps gain detailed control over memory use; Soft Real-Time: Programmers who are interested in real-time programming can exploit the absence of garbage collection: there are no interruptions of unbounded duration at runtime; Interface to the C language: ML Kit applications can call C functions using standard C calling conventions; the region scheme can even take care of allocating and de-allocating regions used by C functions thus invoked. The overall goal with developing the ML Kit with Regions has been to combine the advantages of a high-level, type-safe language (Standard ML, 1997 Definition), with the advantages of low-level languages, namely detailed control over space and time. Indeed, it turns out that the regularity provided by the ML type system makes is possible to infer much more useful information about ML programs than one can reasonably hope for in languages with more liberal type systems. Naturally, the hope is that this technology will promote the use of Standard ML in situations where safety and detailed control of machine resources are important, as indeed is often the case. Since we are using Standard ML as our source language, one can use the ML Kit in conjunction with other Standard ML systems; for example, one can port programs that previously ran on a garbage collection based Standard ML system to run on the Kit; or one may use the Kit simply to gain insight into how a program intended for another system uses memory; or one can develop Standard ML programs directly in the Kit. We have tried all three with good results. A comprehensive technical report "Programming with Regions in the ML Kit" is available from the above web site. The ML Kit with Regions was developed by Mads Tofte, Lars Birkedal, Martin Elsman, Niels Hallenberg, Tommy H{\o}jfeld Olesen (all at DIKU) and Peter Sestoft and Peter Berthelsen (both at KVL). Edinburgh ML 4.0 ---------------- Edinburgh ML 4.0 is an implementation of the core language (without the module system). It uses a bytecode interpreter, which is written in C and runs on any machine with 32 bit words, a continuous address space and a correct C compiler. Ports to various 16 bit machines are underway. The bytecode interpreter can be compiled with switches to avoid the buggy parts of the C compilers that we've used it with (as far as I know none of them worked correctly). Edinburgh ML 4.0 is available from the LFCS. See the WWW link: http://www.dcs.ed.ac.uk/lfcsinfo/index.html A port to PCs with 386SX processors or better is available by FTP from ftp.informatik.uni-muenchen.de, in the file pub/comp/programming/languages/sml/ibmpc/edml3864.exe. Contact Joern Erbguth (erbguth@juris-sb.de) for more information. Also, there are apparently 8086 and 80386-specific ports of Edinburgh ML 3.5 in the same location. The 386 port is in the file edml3863.exe. There are other Edinburgh (PC-)ports of ML including an OS/2 2.x, an OS/2 PM and a Dos version. A new version has just been made ready and is available at forwiss.uni-passau.de ( in pub/ibmpc/os2/lang/sml/sml04.zip. It is about 360K long (short?). All 3 programs have in common (all in one .zip): - true 32 Bit applications - easy to install, easy to use - As far as I know they work stable (except the DOS version working as a Windows window [you can use it with Windows but it crashes on *exit*]) - they don't require expensive hardware (and they don't need a co-processor) To be more specific: OS/2 PM OS/2 DOS OS >= OS/2 2.0+ServPak >= OS/2 2.0 >= DOS 5.0 Edit PM, GUI, Standard command history integrated editor (cut&paste) HW >= 386/33, 8MB >= 386/33 4MB >= 386sx, 2MB lots of MB and fast graphics ad. recommended Help online online (+ML ref. in german) There's also an amiga port of Edinburgh ML available on all aminet ftp sites (amiga users should know which these are) in dev/lang, called "sml4.1.02.lha". The standard version needs a 68020 or better and an FPU but there is a 68000-only version as well. MicroML ------- MicroML is an interpreter for core SML that runs on IBM PCs, from the Department of Computing Science at the Umea University in Sweden. It implements the core language except for records. A 80286 processor or better is recommended, but it runs even on a 8086. MicroML is available by anonymous ftp from ftp.cs.umu.se /pub/uml022.zoo. For more information contact Olof Johansson (olof@cs.umu.se). Poly/ML ------- Poly/ML, probably the longest established implementation of Standard ML, is now available at http://www.polyml.org . Poly/ML was originally written in the mid-eighties at Cambridge University. For several years it was marketed by Abstract Hardware Limited who developed it further. Recently the rights were reacquired by Cambridge University Technical Services who have agreed to make Poly/ML freely available. Poly/ML now supports full SML 97 and the Standard Basis Library, along with some non-standard extensions. According to the web page, the compiler source is available, as well as binary releases. Poly/ML is currently available for Linux and Windows on Intel platforms, Sparc/Solaris, and MacOS X. Measurements with several large ML applications shows Poly/ML to be one of the fastest implementations of Standard ML around. Poplog ML --------- Poplog is a portable system including incremental compilers for Pop-11, Common Lisp, Prolog and Standard ML, along with a huge amount of system documentation, teaching materials for AI/Cognitive Science, the Sim_agent Toolkit, vision libraries, and other things. "Poplog" is a trade mark of the University of Sussex, where most of Poplog was developed, starting with Pop-11 on a PDP11/40 computer in the mid 70s, inspired by the Edinburgh AI language Pop2. The full Poplog system (as of version 15.53) is available free of charge, including source code. For more information, see ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/poplog.info.html For information about the free versions available, and various teaching and research support libraries for AI see: ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/freepoplog.html This includes versions of Poplog V15.53 for Solaris+Sparc (works on Solaris 7 as well as earlier versions) PC Linux (RedHat 5.x, and 6.0) with or without motif There are slightly older versions for PC+Solaris86 Dec Alpha + Digital unix Reduced version (no graphics, nothing that depends on X) PC+Windows95/98 (may work on NT also?) Poplog comes with masses of online documentation: this can be browsed at ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/doc/ Pop-11 documentation can be found at ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/primer/START.html or ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/ A slightly zany tutorial file on story grammars can be read in ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/teach/storygrammar COMP.LANG.POP Comments and questions about Poplog and Pop-11 may be posted to the comp.lang.pop newsgroup, which is linked to an email list. See ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/newsgroup.txt (Please do NOT post general conference announcements, advertisements, etc.) Adrian John Howard (adrianh@cogs.susx.ac.uk) has a WWW page for Poplog: http://www.cogs.susx.ac.uk/users/adrianh/poplog.html Harlequin MLWorks ----------------- Harlequin MLWorks is no longer available as a commercial product. http://www.harlequin.com/products/mlworks_message.html MLJ --- MLj is a Standard ML compiler which produces Java bytecodes. MLj 0.2 compiles the functor-free subset of the new SML'97 language plus some new language extensions for straightforward interlanguage working with Java. It produces compact standalone compiled code which can be run on any computer with a Java Virtual Machine. This release includes a number of improvements over the original release (0.1), including significantly better compilation times, better code generation, more complete Basis library support, better error messages and friendlier language extensions for interlanguage working. Although there are limitations (most importantly a lack of general tail-call optimisation), MLj is quite usable for many small-to-medium projects. It can be used to write portable ML applications and applets which make use of Java's standard libraries for graphics, database access, networking, etc. and which interwork with third-party Java code. Visit the new MLj website at http://www.dcs.ed.ac.uk/~mlj/ to find out more about MLj, see some example ML applets and download the MLj 0.2 distribution. The compiler is distributed as source+standalone binaries for Sparc/Solaris, Intel/Linux and Intel/Windows, and in source-only form for compilation under SML/NJ version 110. It is covered by the GNU Public License version 2. MLj was written by Nick Benton, Andrew Kennedy and George Russell of the Cambridge Research Group of Persimmon IT, Inc. Please note that Persimmon IT will no longer distribute or support the compiler; instead, Ian Stark and Tom Chothia of the University of Edinburgh have kindly offered to host the new download site. The original authors continue to develop the compiler and it is hoped that further releases will take place in the future. MLton ----- MLton is a whole-program optimizing compiler for the Standard ML programming language. MLton runs on X86 machines with Linux, FreeBSD, or Cygwin/Windows. MLton has the following features. + Generates standalone executables with good runtime performance + SML 97 compliant, with a mostly complete basis library + Fast IntInf based on the GNU multiprecision library (gmp) + Fast C FFI + Profiling + Supports large amounts of memory and large arrays. + Libraries for continuations, interval timers, random numbers, resource limits, resource usage, signal handlers, sockets, system logging, threads, and heap save and restore For more information, go to the MLton home page. http://www.mlton.org/ Send comments, questions, and bug reports to MLton@mlton.org. HaMLet ------ HaMLet is a faithful implementation of the Standard ML programming language (SML'97). It aims to be * an accurate reference implementation of the language specification, * a platform for experimentation with the language semantics or extensions to it, * a useful tool for educational purposes. The implementation is intended to be as direct a translation of the language formalisation found in the Definition of Standard ML as possible, modulo bug fixes. It tries hard to get all details of the Definition right. The HaMLet source code * implements complete Standard ML, * closely follows the structure of the Definition, with lots of cross references, * conforms to the latest version of the Standard ML Basis Library, * is written entirely in Standard ML, with the ability to bootstrap, * may readily be compiled with SML/NJ, Moscow ML, or MLton. HaMLet can perform different phases of execution - like parsing, elaboration (type checking), and evaluation - selectively. In particular, it is possible to execute programs in an untyped manner, thus exploring the universe where even ML programs "can go wrong". http://www.ps.uni-sb.de/hamlet/ SML.NET ------- SML.NET is a whole program compiler for full Standard ML that compiles to the .NET Common Language Runtime. For more information, see http://www.cl.cam.ac.uk/Research/TSG/SMLNET/ Alice ML -------- Alice ML is a functional programming language based on Standard ML, extended with rich support for concurrent, distributed, and constraint programming. Alice ML extends Standard ML with several new features: * Futures: laziness and light-weight concurrency with data-flow synchronisation * Higher-order modules: higher-order functors and abstract signatures * Packages: integrating static with dynamic typing and first class modules * Pickling: higher-order type-safe, generic & platform-independent persistence * Components: platform-independence and type-safe dynamic loading of modules * Distribution: type-safe cross-platform remote functions and network mobility * Constraints: solving combinatorical problems using constraint propagation and programmable search The Alice System is a rich open-source programming system featuring the following tools: * Virtual machine: a portable VM with support for just-in-time compilation * Interactive system: an interpreter-like interactive toplevel * Batch compiler: separate compilation * Static linker: type-safe bundling of components * Inspector: a tool for interactively inspecting data structures * Explorer: a tool for interactively investigating search problems * Gtk+: a binding for the Gnome toolkit GUI library The homepage is: http://www.ps.uni-sb.de/alice/ -------------------------------------------------------------------------- 4. Unsupported SML/NJ Ports This section describes various ports of SML/NJ (see section 3) that are not directly supported by the NJ folks. OS/2: ---- An old port of SML/NJ ver. 0.93 to OS/2 exists. The port is no longer being maintained, but may be downloaded from: ftp://ftp.dina.kvl.dk/pub/Staff/Peter.Bertelsen/smlnj/0.93-os2/ Another unmaintained and somewhat incomplete port of SML/NJ ver. 108.10 to OS/2 may be downloaded from: ftp://ftp.dina.kvl.dk/pub/Staff/Peter.Bertelsen/smlnj/108.10-os2/ NEXTSTEP: --------- The CSDMteam at the University of Munich proudly presents the port of Standard ML of NJ, version 0.93, to NEXTSTEP for Intel processors. The modified source can be found at ftp.informatik.uni-muenchen.de: /pub/comp/programming/languages/sml/NJ-0.93/93.src.nsfip.tar.Z (please look at the installation instructions in the file README.NeXT.I386). A precompiled binary of the interpreter (gzip'ed) is located at ftp.informatik.uni-muenchen.de:/pub/comp/platforms/next/Developer/languages/ml /sml.0.93.I.b.gz. SVR4: ----- An mplementation for SVR4.0.4 is available from Anthony Shipman (als@tusc.com.au) that fixes the problems with listDir and getWD and includes a full malloc implementation for runtime/malloc.c. Contact Anthony for more info. -------------------------------------------------------------------------- 5. Where can I find documentation on ML? THE DEFINITION -------------- Robin Milner, Mads Tofte, Robert Harper and Dave MacQueen The Definition of Standard ML (Revised) MIT Press, 1997, xiii + 114 pp. ISBN 0-262-63181-4 (paper) Robin Milner, Mads Tofte and Robert Harper The Definition of Standard ML MIT, 1990. ISBN: 0-262-63132-6 Robin Milner and Mads Tofte Commentary on Standard ML MIT, 1991 ISBN: 0-262-63137-7 TEXTS (date order) ----- Ake Wikstrom Functional Programming Using Standard ML Prentice Hall 1987 ISBN: 0-13-331661-0 Chris Reade Elements of Functional Programming Addison-Wesley 1989 ISBN: 0-201-12915-9 (see http://www.kingston.ac.uk/~bs_s075/EofFP.html for information and updates) Stefan Sokolowski Applicative High Order Programming: The Standard ML perspective Chapman & Hall 1991 ISBN: 0-412-39240-2 0-442-30838-8 (USA) Ryan Stansifer ML Primer Prentice Hall, 1992 ISBN 0-13-561721-9 Colin Myers, Chris Clack, and Ellen Poon Programming with Standard ML Prentice Hall, 1993 ISBN 0-13-722075-8 (301pp) Jeffrey D. Ullman Elements of ML Programming Prentice-Hall, 1993 (Oct. 15) ISBN: 0-13-184854-2 (See Comp.Lang.ML archives, message from Ullman dated 22 Sep 1993 for chapter headings.) Rachel Harrison Abstract Data Types in Standard ML John Wiley & Sons, April 1993 ISBN: 0-471-938440 Richard Bosworth A Practical Course in Functional Programming Using Standard ML, McGraw-Hill 1995, ISBN: 0-07-707625-7. Elementary Standard ML Greg Michaelson UCL Press 1995 ISBN: 1-85728-398-8 PB (available at <ftp://ftp.macs.hw.ac.uk/pub/funcprog/gjm.book95.ps.Z>) Lawrence C Paulson ML for the Working Programmer (2nd Edition, ML97) Cambridge University Press 1996 ISBN: 0-521-56543-X (paperback), 0-521-57050-6 (hardback) http://www.cl.cam.ac.uk/users/lcp/MLbook/ Jeffrey D. Ullman Elements of ML Programming (2nd Edition, ML97) MIT Press 1997 http://www-db.stanford.edu/~ullman/emlp.html G.Cousineau & M.Mauny The Functional Approach to Programming Cambridge University Press, 1998 [Uses CAML] M.Felleisen & D.P.Friedman The Little MLer MIT Press, 1998 Chris Okasaki Purely Functional Data Structures Cambridge University Press, 1998. ISBN: 0-521-63124-6 Michael R. Hansen, Hans Rischel Introduction to Programming using SML Addison-Wesley, 1999 ISBN: 0-201-39820-6 http://www.it.dtu.dk/introSML John Reppy Concurrent Programming in ML Cambridge University Press 1999 ISBN: 0-521-48089-2 INFORMATION AVAILABLE BY INTERNET --------------------------------- The Fox project at CMU has a WWW page for information about Standard ML, which also includes the first two reports below: http://foxnet.cs.cmu.edu/sml.html The following report covers all of Standard ML, and is available at: ftp://ftp.cs.cmu.edu/afs/cs/project/fox/mosaic/intro-notes.ps A revised, though still unstable web version of these notes is available at: http://www.cs.cmu.edu/People/rwh/introsml Robert Harper Introduction to Standard ML LFCS Report Series ECS-LFCS-86-14 Laboratory for Foundations of Computer Science Department of Computer Science University of Edinburgh Nov. 1986 (revised Jan. 1989 by Nick Rothwell and Kevin Mitchell) The following report includes an introduction to Standard ML and 3 lectures on the modules system. Available from: http://foxnet.cs.cmu.edu/sml.html Mads Tofte Four Lectures on Standard ML LFCS Report Series ECS-LFCS-89-73 Laboratory for Foundations of Computer Science Department of Computer Science University of Edinburgh March 1989 Extended ML (EML) is a framework for specification and formal development of SML programs. EML specifications look just like SML programs except that logical axioms are allowed in signatures and in place of code in structures and functors. Some EML specifications are executable, making EML a "wide-spectrum" language which can be used to express every stage in the development of a SML program from the initial high-level specification to the final program itself and including intermediate stages in which specification and program are intermingled. Formally developing a program in EML yields an interconnected collection of generic SML modules, each with a complete and accurate axiomatic specification of its interface with the rest of the system. Information about EML is available from http://www.dcs.ed.ac.uk/home/dts/eml/ Le projet Cristal at INRIA Rocquencourt has set up a WWW server for information regarding its activities, especially the Caml and Caml Light compilers. The server also offers on-line access to documentation, publications and to a database of BibTex references in CS. Welcome to: http://pauillac.inria.fr/ Please report problems and suggestions to Xavier.Leroy@inria.fr. Richard Botting has taken Larry Paulson's SML Syntax and translated it into a form that can be read by mosaic, netscape, lynx and other WWW browsers. The URL is: http://www.csci.csusb.edu/dick/samples/ml.syntax.html Andrew Cumming has made availible "A Gentle Introduction to ML". It is aimed at students who are reasonably computer literate but who are new to functional programming. It consists largely of questions and diversions broken up into roughly one-hour tutorials, most of the questions have hints which the student can follow up if required. The material is intended to be used alongside ML - sections of code may be copied from the browser window into an ML session. The URL is http://www.dcs.napier.ac.uk/course-notes/sml/manual.html There are some WWW pages based on an info-tree at MIT with a variety of useful information on ML. The URL is: http://www.ai.mit.edu/!info/sml/!!first There is an interesting collection of news articles at: http://www.cs.jcu.edu.au/ftp/web/FP/ml.html -------------------------------------------------------------------------- 6. Where can I find library code? a. The Standard ML ('97) Basis Library In order to enhance the usefulness of SML as a general-purpose programming language, a group of SML implementers, including representatives of Harlequin's ML Works, Moscow ML and SML/NJ, have put together a proposal for an SML Basis Library, containing a collection of modules to serve as a basic toolkit for the SML programmer. The current draft is available on the web at http://SML.sourceforge.net/Basis/ b. The Edinburgh SML Library The Edinburgh SML Library provides a consistent set of functions on the built-in types of the language and on vectors and arrays, and a few extras. It includes a "make" system and a consistent set of parsing and unparsing functions. The library consists of a set of signatures with sample portable implementations, full documentation, and implementations for Poly/ML, Poplog ML and SML/NJ that use some of the non-standard primitives available in those systems. It is distributed with Poly/ML, Poplog ML and Standard ML of New Jersey. It is also available from the LFCS. The library documentation is available as a technical report from the LFCS (reports@dcs.ed.ac.uk) and costs 5 pounds or 10 US dollars. The LaTeX source of the report is included with the library. Dave Berry The Edinburgh SML Library LFCS Report Series ECS-LFCS-91-148 Laboratory for Foundations of Computer Science Department of Computer Science University of Edinburgh April 1991 c. The SML/NJ Library The SML/NJ Library is distributed with the SML of New Jersey compiler. It provides a variety of utilities such as 2-dimensional arrays, sorting, sets, dictionaries, hash tables, formatted output, Unix path name manipulation, etc. The library compiles under SML/NJ but should be mostly portable to other implementations. d. SML_TK sml_tk is a Standard ML package providing a portable, typed and abstract interface to the user interface description and command language Tcl/Tk. It combines the advantages of the Tk toolkit with the advantages of Standard ML (bypassing the shortcomings of Tcl), allowing the implementation of graphical user interfaces in a structured and reusable way, supported by the powerful module system of Standard ML. For more information, and to obtain sml_tk, please point your web browser to the sml_tk homepage at http://www.informatik.uni-bremen.de/~cxl/sml_tk or contact us at smltk@informatik.uni-bremen.de. e. Caml-light libraries (Included in the Caml Light distribution unless otherwise noted) (Most of these libraries are also available for Objective Caml) CAML-TK TK is a GUI library for the TCL language. Normally, TK is controlled from TCL. The Caml-TK interface provides a Caml Light library to control TK from Caml Light programs. Thus, TK can be used to program graphical user-interfaces in Caml Light without knowledge of the TCL language. LIBGRAPH The "libgraph" library implements basic graphics primitives (line and text drawing, bitmaps, basic event processing) for the Caml Light system. It is portable across all platforms that run Caml Light: X-Windows, Macintosh, MSDOS. CAMLWIN Camlwin is a GUI library for Caml Light that provide all the classical graphic objects: buttons, string and text editors, list... and a high level object like windowed file selector. It is based on an extension of the "libgraph" library and therefore highly portable. Its main interest is its ability to compile the same code under many systems. At present time, it works under DOS, Windows, and X11 with unix. Camlwin is distributed at: ftp.inria.fr:lang/caml-light/Usercontribs/camlwin The reference manual is also available on the WWW at: http://liasc.enst-bretagne.fr/~saunier LIBNUM The "libnum" library implements exact-precision rational arithmetic for Caml Light. It is built upon a state-of-the-art arbitrary-precision integer arithmetic package, and therefore achieves very good performance (it's much faster than Maple, for instance). LIBUNIX The "libunix" library makes many Unix system calls and system-related library functions available to Caml Light programs. It provides Caml programs with full access to Unix capabilities, especially network sockets. LIBSTR The "libstr" library for Caml Light provides high-level string processing functions, including regular expression matching and substitution. It is intended to support the kind of text processing that is usually performed with "sed" or "perl". f. The Qwertz Toolbox The qwertz toolbox, a library of Standard ML modules with an emphasis on symbolic Artificial Intelligence programming, may now be obtained by anonymous ftp at: ftp.gmd.de:gmd/ai-research/Software/qwertz.tar.gz The qwertz.tar.gz file is a tar archive compressed using the the GNU gzip program. Use the gunzip program to decompress it. The README file explains how the install the library. The toolbox includes: symbols and symbolic expressions, tables including association lists, sets, queues and priority queues, streams, heuristic search including A* and iterative deepening, and an ATMS reason maintenance system. -------------------------------------------------------------------------- 7. Theorem Provers and ML (Collected by Paul Black, pblack@cs.berkeley.edu. Thanks Paul!) - LCF (Edinburgh LCF and Cambridge LCF) * originally written in the Edinburgh dialect of ML from which SML developed. "Logic and Computation: Interactive Proof with Cambridge LCF" also by Lawrence C. Paulson. (Describes a Standard ML [core language only] version of LCF.) The port was done by M. Hedlund, then at Rutherford Appleton Labs, UK. It is available by anon. ftp from ftp://ftp.cl.cam.ac.uk/ml/lcf.tar.gz. - Lego (LFCS, Edinburgh Univ., SML) * originally developed in CAML * latest version (5) now runs under SML/NJ * only higher-order resolution * available via anon. ftp from ftp.dcs.ed.ac.uk:/pub/lego - HOL90 Authors = Konrad Slind, Elsa Gunter kxs@cl.cam.ac.uk, elsa@research.att.com http://www.cl.cam.ac.uk/Research/HVG/HOL/ hol90 is a free implementation in SML/NJ of Mike Gordon's HOL logic (a polymorphic version of Church's Simple Type Theory). The system provides a lot of automated support including: - a powerful rewriting package; - pre-installed theories for booleans, products, sums, natural numbers, lists, and trees; - definition facilities for recursive types and recursive functions over those types (mutual recursion is also handled); - extensive libraries for strings, sets, group theory, integers, the real numbers, wellordered sets, automatic solution of goals involving linear arithmetic, tautology checking, inductively defined predicates, Hoare logic, Chandy and Misra's UNITY theory, infinite state automata, and many others. The HOL community has a lively mailing list accessible at info-hol-request@leopard.cs.byu.edu and a yearly user's meeting that alternates between Europe and North America. hol90 is available by anonymous ftp from machine = ftp.informatik.tu-muenchen.de/local/lehrstuhl/nipkow/slind/hol90/ or machine = ftp.research.att.com/dist/ml/hol90/ Tim Leonard mentions that a description of the variant of ML used in HOL88 is online at the following url: http://lal.cs.byu.edu/lal/holdoc/Description/ML/ML.html - NuPrl (from Bob Constable`s group at Cornell) - Isabelle (Lawrence C. Paulson, Cambridge and Tobias Nipkow, Munich) * has integrated rewriting and classical reasoning * a generic proof tool supporting the following formalisms among others: i) FOL - first order logic ii) HOL - higher order logic iii) LCF - Logic of computable functions vi) ZF - Zermelo-Fraenkel set theory * There's a WWW page: http://www.cl.cam.ac.uk/Research/HVG/Isabelle/ * There's also a mailing list: isabelle-users@cl.cam.ac.uk - MERILL (Brian Matthews, U. of Glasgow & Rutherford Appleton Laboratory) * written in standard ML * a general purpose order-sorted equational reasoning system * Allows the user to declare their own object language, allows AC-rewriting and AC-unification of terms and equations, has several completion algorithms, is built on a hierarchy of types known as Order-Sorting, and allows the user to try different termination methods. * available via anonymous ftp from the University of Glasgow, ftp address: ftp.dcs.glasgow.ac.uk ( * Brian Matthews, brian@dcs.glasgow.ac.uk or bmm@inf.rl.ac.uk - FAUST (Karlsruhe) * a HOL add-on written in ML. * ftp from goethe.ira.uka.de ( - Alf * written in SML * An implementation of Martin-Lofs type theory with dependent types * Proof editor * available by anonymous ftp from cs.chalmers.se * only higher-order resolution - Coq * written in Objective CAML (previous versions were written in CAML and Caml-Light) * implements the Calculus of Inductive Constructions a logical framework suitable for abstract mathematical formalisation and functional program manipulation. * available via anon. ftp from ftp.ens-lyon.fr:/pub/LIP/COQ/V6.1 ftp.inria.fr:INRIA/Projects/coq/coq/V6.1 * possible contact: coq@pauillac.inria.fr more information : http://pauillac.inria.fr/coq/systeme_coq-eng.html * Coq has an interface based on Centaur developed by the CROAP project at INRIA Sophia-Antipolis : http://www.inria.fr/croap/ctcoq/ctcoq-eng.html - ICLHOL/ProofPower (Lemma 1) * a commercial system using a reimplementation of HOL in SML * http://www.lemma-one.com/ProofPower/index/index.html - Lamdba/DIALOG (Abstract Hardware Ltd) * a commercial tool written in Poly/ML * contact ahl@ahl.co.uk - Twelf (Frank Pfenning & Carsten Schuermann, Carnegie Mellon Univ) * Twelf is a meta-logical framework for deductive systems. * Twelf includes an implementation of LF, including type reconstruction, the Elf constraint logic programming language, and a preliminary inductive meta-theorem prover for LF. * The implementation is written in SML'97 and has been tested under SML/NJ and MLWorks on Unix and Windows platforms. It also includes a complete user's manual, tutorial, example suites, and an Emacs mode. * Further information, including download instructions, information on the mailing list, publications, etc. can be found at http://www.cs.cmu.edu/~twelf - Definitional Reasoning (Univerity of Tasmania) * developed with SML/NJ * a study of Boolean Affine Combinations (a highly formal case construct) * includes a rich set of term rewriting combinators * ftp://hilbert.maths.utas.edu.au/pub/DR.tar.gz * mail to piggy@acm.org for more information. References "ML for the Working Programmer" by Lawrence C. Paulson contains a small first-order theorem prover. Paulson also has a good chapter on writing theorem provers in ML in "Handbook of logic in computer science", Edited by: S. Abramsky, Dov M. Gabbay, and T.S.E. Maibaum. Oxford : Clarendon Press, 1992-. CALL#: QA76 .H2785 1992 Others Edinburgh's Concurrency Workbench and Sussex's Process Algebra Mauipulator are also ML systems of note, though neither are interactive theorem provers. -------------------------------------------------------------------------- 8. Miscellaneous Where can I find out about SML'97? Look at: http://cm.bell-labs.com/cm/cs/what/smlnj/sml97.html How do I write the Y combinator in SML without using a recursive definition (i.e. "fun" or "let rec")? datatype 'a t = T of 'a t -> 'a val y = fn f => (fn (T x) => (f (fn a => x (T x) a))) (T (fn (T x) => (f (fn a => x (T x) a)))) Where can I find an X-Windows interface to SML? Poly/ML, Poplog/ML, MLWorks and SML/NJ all come with X-Windows interfaces. See the appropriate entries under section 3. In addition, Poly/ML interfaces to the industry standard OSF/Motif toolkit. How do I call a C function from SML/NJ? The new versions of SML/NJ provide much better support for calling out to C than version 93 did. There is a discussion of how to use the C function interface off of the SML/NJ web page at http://cm.bell-labs.com/cm/cs/what/smlnj/doc/SMLNJ-C/index.html Where can I find an emacs mode for SML? Look in the "Contributed Software" section of the SML/NJ distribution page at http://cm.bell-labs.com/cm/cs/what/smlnj/software.html Nowadays sml-mode works well with Emacs 19 and XEmacs 19, as well as a number of different SML compilers. Stefan Monnier has released a new version (3.9.3) with a number of changes, including improvements to the indentation algorithm. The new version is available at ftp://rum.cs.yale.edu/pub/monnier/sml-mode What is the value restriction? The value restriction is a feature of SML '97 which was introduced to address some issues with polymorphism in the presence of effects. The basic idea is that when a variable is bound to a polymorphic expression, it must be the case that the expression is tantamount to a value: that is, that it is guaranteed not to raise an exception or allocate memory. For the purposes of typechecking, the class of values is conservatively approximated by the syntactic notion of "non-expansiveness". Values (non-expansive expressions) are: - functions - constants - variables - records of values - constructors applied to values So for example, while in the following code f has type 'a -> 'b -> 'b, g cannot be given the type 'b -> 'b because of the value restriction. fun f x y = y val g = f 3 The expression (f 3) is polymorphic (at type 'b -> 'b) but is not a value, and so the value restriction forbids g from being bound polymorphically. Either the code will be rejected, or g will be given a useless "dummy" type. In practice, this is usually easy to get around by eta-expanding: fun f x y = y val g = fn x => f 3 x More information on the value restriction is available from a number of sources, in particular: - Section 4.7 of "The Definition of Standard ML". (see above) - Pages 321-326 of Paulson's "ML for the working programmer". (see above) - http://cm.bell-labs.com/cm/cs/what/smlnj/doc/Conversion/types.html#Value This includes discussion of the particulars of SML/NJ's treatment of the value restriction. - Extensive discussion in the comp.lang.ml archives. What is the difference between OCaml and Standard ML? Jen Olsson has created a small chart comparing the OCaml and Standard ML syntax: see http://www.csd.uu.se/~jenso/programming/sml_vs_ml.txt . An extended version written by Andreas Rossberg can be found at http://www.ps.uni-sb.de/~rossberg/SMLvsOcaml.html In addition to the original page it covers modules, records, and some more stuff.