implement ExecsExeclib;

include "sys.m"; sys: Sys;
include "draw.m";

ExecsExeclib: module {
	init: fn(ctxt: ref Draw->Context, args: list of string);
};

# Usually, this would be placed into something like "execlib.m",
# but it's fine here.
Execlib: module {
	hailstone: fn(i: big): list of big;
};

init(nil: ref Draw->Context, nil: list of string)
{
	sys = load Sys Sys->PATH;
	# This program expects that the result of compiling Execlib is execlib.dis,
	# so you'll need to adjust this line if you used a different filename.
	lib := load Execlib "execlib.dis";
	if(lib == nil)
		die("Couldn't load execlib.dis");

	counts := array[352] of { * => 0 };
	for(i := 1; i < 100000; i++) {
		counts[len lib->hailstone(big i)]++;
	}

	max := 0;
	maxi := 0;
	for(i = 1; i < len counts; i++) {
		if(counts[i] > max) {
			max = counts[i];
			maxi = i;
		}
	}
	sys->print("The most common sequence length is %d (encountered %d times)\n", maxi, max);
}

die(s: string)
{
	sys->fprint(sys->fildes(2), "runls: %s: %r", s);
	raise "fail:errors";
}