LimitMinMax.hx

class LimitMinMax implements haxe.rtti.Meta
{
	public var max:Float;
	public var min:Float;

	public function new(max, min)
	{
		this.max = max;
		this.min = min;
	}
}

Test.hx

import LimitMinMax;

class Test 
{
	@LimitMinMax public var field2:Float; //error: limitMinMax takes two arguments

	@LimitMinMax(10, 0) public var field3:Float; //alright! -> if you want to exclude this, do a verification step with macros

	@LimitMinMax(0, 10) public var field3:Float; //alright!

	@mylib.Limit.LimitMinMax(0, 10) public var field3:Float; //alright, with fully qualified name!

	public static function main() 
	{
		new B();
		var metas = haxe.rtti.Meta.getFields(Test);
		trace(Std.is(metas.field3, LimitMinMax)); //true
  	}
}

I tried to follow through and think about all the different use cases:

import LimitMinMax;

class Test 
{
    // Use constructor.  Must be a valid type that has been imported.
    @LimitMinMax(0,10)
    public var field1:Float; //alright!

    // Use fully qualified name, constructor.  Must be a valid type.
    @mylib.Limit.LimitMinMax(0, 10) 
    public var field2:Float;

    // Use local, not typed metadata.  Name follows local variable naming rules in haxe (must start lower case character, no periods)
    @debug @values(-1,100) 
    var x : Int;

    // Set typed metadata properties - Do we allow any of this?
    @LimitMinMax.min(0) 
    @LimitMinMax.max(10) 
    var y : Int;

    // Or once it's imported, even use it simpler
    @min(0) 
    @max(10) 
    var z : Int;

    // Current generic boolean metadata (if it's defined, true, if it is never defined, false)
    @test
    function myTest() {}

    // The namespaced equivalent of that?
    @munit.Tests.myTest
    function myTest() {}

    // Or use a constructor?
    @munit.Test(true)
    function myTest() {}

    // Or something else?
}

The issues to resolve:

• Do we still support local, untyped metadata?
• And if we do, how to distinguish between typed and untyped?
• And then with typed metadata, can we access the properties or only use the constructors?
• What is the typed and namespaced equivalent of metadata with no content, eg "@test"