The ML family of programming languages are statically-typed (with type-inference),
strict, impure [functional programming] languages. Typically these languages are
good at symbol manipulation (e.g., they make great languages for implementing
compilers etc) and general algorithmic work. ML dates back to the 1970's when it
was created as the ''Meta-Language'' for the Edinburgh LCF theorem-prover. It
can run with similar performance to [C] in some situations, but includes many higher
level features such as garbage collection, type inference (i.e., the compiler will
deduce what types terms should have rather than you having to explicitly annotate
them), and pattern matching. See [http://www.smlnj.org/sml.html] for a brief
summary of [SML%|%Standard ML%|%] features. There are various dialects of ML in addition
to Standard ML, such as [OCaml] which adds [OO] capabilities, and Alice ML
[http://www.ps.uni-sb.de/alice/] which
adds support for (declarative) concurrency and type-safe distributed programming.

An example SML program (here defining a complex number type) is:

 structure Complex =
 struct
     type t        = real * real;
     val  zero     = (0.0, 0.0);
     val  i        = (0.0, 1.0);
     fun  sum   ((x, y), (x', y')) = (x+x', y+y') : t;
     fun  diff  ((x, y), (x', y')) = (x-x', y-y') : t;
     fun  prod  ((x, y), (x', y')) = (x*x' - y*y', x*y' + x'*y) : t;
     fun  recip ((x, y), (x', y')) = let val t = x*x' + y*y'
                                     in  (x/t, ~y/t) end;
     fun quo    (z, z')            = prod(z, recip z');
 end;
 val a = (0.3, 0.0);
 val b = Complex.sum(a, Complex.i);
 val c = Complex.sum(b, (0.7, 0.0));
 val d = Complex.prod(c, c);

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http://www.informatik.uni-bremen.de/~cxl/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 allows the implementation of graphical user interfaces in a structured and reusable way, supported by the powerful module system of Standard ML.

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