New HLVM examples

HLVM is a garbage collected virtual machine built upon LLVM:

  http://forge.ocamlcore.org/projects/hlvm/

The development of HLVM was described in a series of three OCaml Journal
articles that turned out to be among our most popular. Consequently, we have
decided to run another series of related articles that build upon this
foundation in order to develop complete compilers. The first article
describes a compiler written in only 228 lines of code that can execute
interesting programs:

http://ocamlnews.blogspot.com/2009/06/compiler-development-part-1.html

For example, the compiler described in the article can execute the following
OCaml-like program to print the Mandelbrot set:

# let rec pixel((n, zr, zi, cr, ci) : int * float * float * float * float) :
unit =
if n = 65536 then print_char ' ' else
if zr * zr + zi * zi >= 4.0 then print_char '.' else
pixel(n+1, zr * zr - zi * zi + cr, 2.0 * zr * zi + ci, cr, ci);;
# let rec row((i, j, n) : int * int * int) : unit =
if i>n then () else
begin
let cr = 2.0 * float_of_int i / float_of_int n - 1.5 in
let ci = 2.0 * float_of_int j / float_of_int n - 1.0 in
pixel(0, 0.0, 0.0, cr, ci);
row(i+1, j, n)
end;;
# let rec col((j, n) : int * int) : unit =
if j>n then () else
begin
row(0, j, n);
print_char '\n';
col(j+1, n)
end;;
# let rec mandelbrot(n : int) : unit =
col(0, n);;
# mandelbrot 77;;

In particular, our compiler runs this program interactively 50x faster than
the OCaml top-level and 60% faster than native-code compiled OCaml!

The complete source code of HLVM and the example programs including this
compiler are freely available under a BSD license and may be downloaded from
HLVM's SVN repository as follows:

svn checkout svn://svn.forge.ocamlcore.org/svnroot/hlvm