di.php

<?php

class B {}

class A {
  protected $b;
  
  public function __construct()
  {
    $this->b = new B();
  }
}

$a = new A();
?>
<?php
class B {}

class A
{
  protected $b;
  
  public function __construct(B $b)
  {
    $this->b = $b;
  }
}

$b = new B();
$a = new A($b);

di.xml

<parameters>
    <parameter key="a.class">A</parameter>
    <parameter key="b.class">B</parameter>
</parameters>

<services>
    <service id="b" class="%b.class%">
    </service>

    <service id="a" class="%a.class%">
        <argument type="service" id="b"/>
    </service>
</services>

di.yaml

parameters:
  a.class: A
  b.class: B

services:
  b:
    class: %b.class%
  
  a:
    class: %a.class%
    arguments: [@b]

di2.php

<?php

$a = $container->get('a'); 
// $a = new A(new B());

diflow.php

<?php
class Baobaz_Training_Model_Profile_Catalog_Import_Simple extends BFlow_Core_Model_Flow_Profile
{
    public function __construct(
        BFlow_Core_Model_Flow_Action $validatorAction,
        BFlow_Core_Model_Flow_Action $parserAction,
        BFlow_Core_Model_Flow_Action $writerAction,
        \Psr\Log\LoggerInterface $logger
    ) {
        $this->validatorAction = $validatorAction;
        $this->parserAction = $parserAction;
        $this->writerAction = $writerAction;
        $this->logger = $logger;
    }
}