Conditional Branching

Fork operations enable workflows to select a branch based on a criteria. It's equivalent to if instructions but allow for static rendering of the workflow.

val doA = WIO.pure(MyState(1)).autoNamed
val doB = WIO.pure(MyState(2)).autoNamed

val fork: WIO[MyState, Nothing, MyState] =
  WIO
    .fork[MyState]
    .matchCondition(_.counter > 0, "Is counter positive?")(
      onTrue = doA,
      onFalse = doB,
    )

Rendering Outputs

Flowchart

BPMN

Model

{
  "branches" : [
    {
      "meta" : {
        "name" : "Do A",
        "error" : null
      },
      "_type" : "Pure"
    },
    {
      "meta" : {
        "name" : "Do B",
        "error" : null
      },
      "_type" : "Pure"
    }
  ],
  "meta" : {
    "name" : "Is counter positive?",
    "branches" : [
      {
        "name" : "Yes"
      },
      {
        "name" : "No"
      }
    ]
  },
  "_type" : "Fork"
}

Drafting Support

Branching comes with drafting support.

val approveStep = WIO.draft.step("Approve")
val rejectStep  = WIO.draft.step("Reject")

val approvalWorkflow = WIO.draft.choice("Review Decision")(
  "Approved" -> approveStep,
  "Rejected" -> rejectStep,
)

Rendering Outputs

Flowchart

BPMN

Model

{
  "branches" : [
    {
      "meta" : {
        "name" : "Approve",
        "error" : null,
        "description" : null
      },
      "_type" : "RunIO"
    },
    {
      "meta" : {
        "name" : "Reject",
        "error" : null,
        "description" : null
      },
      "_type" : "RunIO"
    }
  ],
  "meta" : {
    "name" : "Review Decision",
    "branches" : [
      {
        "name" : "Approved"
      },
      {
        "name" : "Rejected"
      }
    ]
  },
  "_type" : "Fork"
}