Macro example for EzeQL_ - create ".hx" files at macro time, and then go ahead and use them in your code.

build.hxml

-neko Main.hx.n
-main Main
--macro BuildMacro.build()

BuildMacro.hx

import haxe.macro.Expr;
import haxe.macro.Context;
import sys.FileSystem;
import sys.io.File;
import haxe.io.Path;

class BuildMacro 
{
	static function build()
	{
		var className = "DoesNotExist.hx";
		var classDef = "class DoesNotExist { public function new() { trace('Now it does exist'); } }";
		
		addFileToRepo( className, classDef );

		return null;
	}

	static function addFileToRepo( filename:String, definition:String )
	{
		// Figure out the path of "Main.hx", and then put our file in the same spot
		var mainFilePath = FileSystem.fullPath( Context.resolvePath( "Main.hx" ) );
		var classFilePath = Path.directory(mainFilePath) + "/" + filename;

		if ( !FileSystem.exists(classFilePath)) {
			File.saveContent( classFilePath, definition );
		}
	}
}

Main.hx

class Main 
{
	static function main()
	{
		trace ("Haxe!");
		new DoesNotExist();
	}
}