Convert js-style callback to Future, with macro

JS Callback to Future

Convert js-style callback to Future, with macro

abstract.hx

abstract Wrapper(Model) from Model
{
  public inline function find(query:Dynamic):Surprise<Model, Error>
  {
    // insert the above js-style to future code here...
  }
  public inline function update(query:Dynamic, data:Dynamic):Surprise<UpdateResult, Error>
  {
    // modify and insert the above js-style to future code here...
  }
}

macro.hx

package util;

import haxe.macro.Context;
import haxe.macro.Expr;
using tink.MacroApi;

class Macro
{
    public static macro function futurize(expr:Expr):Expr
    {
        var newExpr = expr.transform( replaceCallbacks );
        return macro @:pos(Context.currentPos()) {
          var t = new tink.CoreApi.FutureTrigger();
          $e{transform(expr)};
          t.asFuture();
      };
    }
    
    static function replaceCallbacks(expr:Expr):Expr
    {
        return switch expr {
            case macro $i{"$cb"}: macro @:pos(expr.pos) function(e, d) t.trigger(e != null ? Failure(e) : Success(d));
            case macro $i{"$cb0"}: macro @:pos(expr.pos) function(e) t.trigger(e != null ? Failure(e) : Success(tink.CoreApi.Noise.Noise));
            case other: other;
        };
    }
}

plain.hx

// Convert js-style callback to a future, to better integrate with ufront
var trigger = new FutureTrigger();
myModelManager.find({}, function(err, data) trigger.trigger(err != null ? Failure(err) : Success(data)));
var future = trigger.asFuture();

usage.hx

var findFuture = futurize(myModelManager.find({}, $cb)); 
// countFuture is Surprise<Array<MyModel>, Error>
var updateFuture = futurize(myModelManager.update({}, {data:data}, $cb)); 
// countFuture is Surprise<UpdateResult, Error>
var countFuture = futurize(myModelManager.where('field', value).count($cb)); 
// countFuture is Surprise<Int, Error>
var removeFuture = futurize(myModelManager.remove({}, $cb0));
// removeFuture is Surprise<Noise, Error> (note the zero in $cb0)