build.hxml

-x Main

FTW.hx

import haxe.macro.Expr;

class FTW
{
	public static function build()
	{
		return haxe.macro.Context.getBuildFields().map(transformField);
	}

	static function transformField(field:Field)
	{
		switch (field.kind)
		{
			case FFun(f): transformExpr(f.expr);
			default:
		}
		return field;
	}

	static function transformExpr(expr:Expr) switch (expr)
	{
		case macro @for($init, $cond, $incr) $block:
			transformExpr(block);
			expr.expr = makeLoop(init, cond, incr, block).expr;
		default:
			haxe.macro.ExprTools.iter(expr, transformExpr);
	}

	static function makeLoop(init:Expr, cond:Expr, incr:Expr, block:Expr) return macro
	{
		$init;
		while ($cond)
		{
			$block;
			$incr;
		}
	}
}

Main.hx

@:build(FTW.build())
class Main
{
	static function main()
	{
		@for(var i = 0, i < 10, i++)
		{
			trace('ftw: $i');
		}
	}
}