futureExample.scala

val eventuallyFoo = ServiceOne.get // can be fired in parallel
val eventuallyBar = ServiceTwo.get
val maybeBax = Option(...)


for {
  foo <- eventuallyFoo
  sideEffect = maybeBax.getOrElse('dooo')
  bar <- eventuallyBar
  baz <- DB.get(foo.id, bar.id, sideEffect)

  if baz.someCondition
} yield baz


// de sugars to 

eventuallyFoo.flatMap((foo) => {
  val sideEffect = maybeBaz.getOrElse('doo') // this is an option
  
  eventuallBar.flatMap((bar) =>
    DB.get(foo.id, bar.id, sideEffect)
      .flatMap(baz => {
        baz.filter(_ => _.someCondition)
          .map(_ => baz)        
      }

  )
})