ComparisonWithCurrentApproach.php

<?php

use SimpleBus\Message\Bus\Middleware\MessageBusSupportingMiddleware;
use SimpleBus\Message\Handler\DelegatesToMessageHandlerMiddleware;
use SimpleBus\Message\Handler\Resolver\NameBasedMessageHandlerResolver;
use SimpleBus\Message\Name\NamedMessageNameResolver;

// Consider this is available
$pimple = new \Pimple(); 

// Currently I need to do this:
$commandBus = new MessageBusSupportingMiddleware();

$commandBus->appendMiddleware(
  new DelegatesToMessageHandlerMiddleware(
    new NameBasedMessageHandlerResolver(
      new NamedMessageNameResolver(),
      new CallableMap(
        [
          'command_name' => 'whatever' // Keeping this list is wrong... =(
        ],
        new ServiceLocatorAwareCallableResolver(function ($id) use ($pimple) {
          return $pimple[$id];
        })
      )
    )
  )
);

/*
Issue here comes that now I need to keep a list of all command names and its resolved values somehow.
Problem relies that NameBasedMessageHandlerResolver signature enforces a MessageNameResolver (ok), 
and a CallableMap (which is wrong. it should rely on CallableResolver).
By applying this change, the now reversed dependency (CallableMap => CallableResolver) would require minor changes, 
but CallableResolver implementor could accept a CallableMap (or CallableCollection) and do an index based get.
*/

// My better alternative here (to not keep the list) is to implement my own MessageHandlerResolver, 
// but CallableResolver and Name namespaces are not useful (~50% of library's code).

// I can stretch the usage and force Name namespace to be used, but not a real reason for that...
// Example:

use SimpleBus\Message\Handler\Resolver\MessageHandlerResolver;
use SimpleBus\Message\Name\MessageNameResolver;

final class PimpleMessageHandlerResolver implements MessageHandlerResolver
{
  private $messageNameResolver;
  private $pimple;
  
  public function __construct(MessageNameResolver $messageNameResolver, \Pimple $pimple) 
  {
    $this->messageNameResolver = $messageNameResolver;
    $this->pimple = $pimple;
  }
  
  public function resolve($message) 
  {
    $name = $this->messageNameResolver->resolve($message);
    
    return $this->pimple[$name];
  }
}

$commandBus = new MessageBusSupportingMiddleware();

$commandBus->appendMiddleware(
  new DelegatesToMessageHandlerMiddleware(
    new PimpleMessageHandlerResolver(
      new NamedMessageNameResolver(),
      $pimple
    )
  )
);

PimpleCallableResolver.php

<?php

use SimpleBus\Message\CallableResolver\CallableResolver

final class PimpleCallableResolver implemented CallableResolver
{
  private $pimple;
  
  public function __construct(\Pimple $pimple) 
  {
    $this->pimple = $pimple;  
  }
  
  public function resolve($name)
  {
    return $pimple[$name];
  }
}

PimpleCommandBus.php

<?php

use SimpleBus\Message\Bus\Middleware\MessageBusSupportingMiddleware;
use SimpleBus\Message\Handler\DelegatesToMessageHandlerMiddleware;
use SimpleBus\Message\Handler\Resolver\NameBasedMessageHandlerResolver;
use SimpleBus\Message\Name\NamedMessageNameResolver;

// Consider this is available
$pimple = new \Pimple(); 

// I should be able to do this:
$commandBus = new MessageBusSupportingMiddleware();

$commandBus->appendMiddleware(
  new DelegatesToMessageHandlerMiddleware(
    new NameBasedMessageHandlerResolver(
      new NamedMessageNameResolver(),
      new PimpleCallableResolver($pimple)
    )
  )
);