Sample code for abstract macro question over on the Haxe mailing list - https://groups.google.com/d/msg/haxelang/0IBfsEs3OHg/Hx9DfmDTAwAJ

build.hxml

-cp src
-debug
-main Main

--each

-js bin/hasString.js

hasString.js

// Generated by Haxe 3.3.0 (git build development @ 6163882)
(function () { "use strict";
var Main = function() {
	console.log(["a","c","b"].toString());
};
Main.main = function() {
	new Main();
};
Main.main();
})();

//# sourceMappingURL=hasString.js.map

hasString.js.map

{
"version":3,
"file":"hasString.js",
"sourceRoot":"file:///",
"sources":["C:/dev/macro_abstractHasString/src/Main.hx","C:/dev/macro_abstractHasString/src/MyAbstract.hx"],
"names":[],
"mappings":";;WAQQ,WACN;AAAA,aC0Be,CA/BD,AAAC,IACD,AAAC,IACD,AAAC;;YDFF,WACb;AAAA;;;;;"
}

Main.hx

package ;

class Main {
	
	public static function main() {
		new Main();
	}
	
	public function new() {
		trace( MyAbstract.getAllValues() );
	}
	
}

MyAbstract.hx

package ;

@:enum abstract MyAbstract(String) from String to String {
	
	public var a = 'a';
	public var b = 'c';
	public var c = 'b';
	
	public static macro function getAllValues() {
		var self = haxe.macro.Context.getType('MyAbstract');
		var results = [];
		
		switch self {
			case TAbstract(_.get() => ab, params):
				/*trace( ab );
				trace( ab.impl.get() );
				trace( ab.impl.get().fields.get() );*/
				for (field in ab.impl.get().statics.get()) {
					switch field.kind {
						case FVar(_, _): 
							try {
								var expr = haxe.macro.Context.getTypedExpr( field.expr() );
								if (expr != null) results.push( expr );
								
							} catch (e:Dynamic) {
								
							}
						
						case _:
							
					}
				};
			case _:
				
		}
		return macro $a{results};
	}
	
}