Haxe Macros - replace "function" with "async function"

Question

I want that when converting haxe to JavaScript, asynchronous is added to its methods. I have Haxe code:

@:expose
class Main implements IAsync {    
    static function main() {
        trace("test");
    }       

    static function testAwait() {
        return 1;
    }
}

And this code is converted to such a code:

. . .
Main.testAwait = function() {
    return Main.test();
};
. . .

I wanted to be able replace function to async function in this code. For example:

Main.testAwait = async function() {
    return Main.test();
};

But I can only change the name of the method for example code macros:

package haxe_test;

import haxe.macro.Expr;
import haxe.macro.Context;   
using haxe.macro.Tools;
using haxe_test.AsyncBuilder;

class BuildHub {
    macro static public function build():Array<Field> {
        var fields = Context.getBuildFields();
        var testFunc:Function = {
            expr: macro return $v{1},
            ret: null,
            params: [],
            args: []
        };

    fields.push({
        name:  "testAwait",
        access:  [Access.AStatic],
        kind: FieldType.FFun(testFunc),
        pos: Context.currentPos(),
    });
    return fields;  
}

How replace function to async function? UPD: I simplified code. Maybe is anythings options compilers or JSGenApi can help me)?

Answer 1

Not sure if you considered something more simple but in Haxe 4 you can do something like this:

class Test {
  static function main() {
    var value = await( async(testAsync) );
    trace(value);
  }

  static function testAsync() return 1;

  static inline function await<T>(fn:Void->Void):T {
    return js.Syntax.code("await {0}()", fn);
  }
  static inline function async<T>(fn:Void->Void):T {
      return js.Syntax.code("async () => {0}()", fn);
  }
}

or do both at same time:

class Test {
  static function main() {
    var value = asyncAwait( testAsync );
    trace(value);
  }

  static function testAsync() return 1;

  static inline function asyncAwait<T>(fn:Void->Void):T {
      return js.Syntax.code("(async () => { await {0}() })()", fn);
  }
}