ComponentMacro.hx

package org.devboy.hxTask;

import neko.Lib;
import haxe.macro.Context;
import haxe.macro.Expr;
import haxe.macro.Type;

class ComponentMacro
{
	private static var idCount = 0;

	@:macro
	public static function build(): Array<Field>
	{
		var pos = haxe.macro.Context.currentPos();
		var mk = function( expr ) return {expr: expr, pos: pos};
        var fields = haxe.macro.Context.getBuildFields();
       	var tint = TPath({ pack : [], name : "Int", params : [], sub : null });
        	fields.push( { name : "ID", doc : null, meta : [], access : [AStatic, APublic], kind : FVar(tint, {expr: EConst(CInt(Std.string(idCount))), pos: pos}) , pos: pos });
        	fields.push( 
	        	{ 
		        	name: "id", 
		        	doc: null, 
		        	meta:[], 
		        	access: [APublic], 
		        	kind: FFun(
		        	{ 
			        	ret: tint, params: [], args: [], expr: mk( EReturn( mk( EConst(CInt(Std.string(idCount)))))) 
			        } ), 
					pos: pos
				} ); 
        idCount++;
        return fields;	
	}	
}

Main.hx

package org.devboy.hxTask;

import neko.Lib;
import haxe.macro.Expr;
import haxe.macro.Context;
import org.devboy.hxTask.ComponentMacro;

class Main
{
	public static function main()
	{
		Lib.println( ComponentA.ID ); //0
		Lib.println( new ComponentA().id() ); //0
		Lib.println( new ComponentA().id() ); //0
		Lib.println( ComponentB.ID ); //1
		Lib.println( new ComponentB().id() ); //1
		Lib.println( new ComponentB().id() ); //1
	}
}

@:autoBuild( org.devboy.hxTask.ComponentMacro.build() )
interface Component 
{
	function id():Int;
}

class ComponentA implements Component
{
	public function new()
	{
		
	}
}

class ComponentB implements Component
{
	public function new()
	{
		
	}
}