Rakefile to generate a mruby mandelbrot example

gistfile1.rb

# Change the path to match the path to your machine.
$mrb_path = File.expand_path("~/src/mruby")
$mrbc = File.join($mrb_path,"/bin/mrbc")

task :default do
  # dumps the Ruby file to disk
  File.open("mandelbrot.rb", "w"){|f| f << mandelbrot_ruby_code }
  # creates the .c file containing mandelbrot char array for the bytecode
  `#{$mrbc} -Bmandelbrot_bytecode ./mandelbrot.rb`
  example_file = wrapper_code(File.read("./mandelbrot.c"))
  File.open("example.c", 'w'){|f| f << example_file}
  cmd = "gcc -I#{$mrb_path}/src -I#{$mrb_path}/include -c example.c -o example.o"
  cmd2 = "gcc -o ./example example.o #{$mrb_path}/lib/libmruby.a"
  `#{cmd}`
  `#{cmd2}`
  print "compiled\n"
  print "executing\n"
  print "You can now run 10 mandelbrots by running ./example\n"
end

def wrapper_code(insert=nil)
  code = <<-EOF
#include "mruby.h"
#include "mruby/irep.h"
#include "mruby/proc.h"

  #{insert}

int
main(void)
{
  /* new interpreter instance */
  mrb_state *mrb;
  mrb = mrb_open();

  /* read and execute compiled symbols */
  int n = mrb_read_irep(mrb, mandelbrot_bytecode);
  mrb_run(mrb, mrb_proc_new(mrb, mrb->irep[n]), mrb_top_self(mrb));

  mrb_close(mrb);

  return 0;
}
EOF
end

def mandelbrot_ruby_code
code = <<-EOF
BAILOUT = 16
MAX_ITERATIONS = 1000

class Mandelbrot
	
	def initialize
		(-39...39).each do |y|
			puts
			(-39...39).each do |x|
				i = iterate(x/40.0,y/40.0)
				print (i == 0) ? "*" :  " "
      end
		end
	end

	def iterate(x,y)
		cr = y-0.5
		ci = x
		zi = 0.0
		zr = 0.0
		i = 0
		
		while true
			i += 1
			temp = zr * zi
			zr2 = zr * zr
			zi2 = zi * zi
			zr = zr2 - zi2 + cr
			zi = temp + temp + ci
			return i if (zi2 + zr2 > BAILOUT)
			return 0 if (i > MAX_ITERATIONS)
		end
	
	end

end

5.times do
  Mandelbrot.new
end
EOF
end