test.yaml

name: test

doc: |
  A little three-node machine that emits messages that depend on a
  parameter and a counter.

  When given a message like

    {"message":{"wants":"tacos"}}

  and assuming a parameters

    {"has": "beer", "n": 3}

  the machine will emit a message like

    {"server": "tacos", "with": "beer", "remaining": 2}

  Subsequent requests decrement the counter until it reaches 0, at
  which point the binding for "has" changes to "water".

paramspecs:
  has:
    doc: What the user has on hand.
    primitiveType: string
  n:
    doc: The number that we have.
    primitiveType: int

patternsyntax: json

nodes:
  start:
    doc: |
      The starting node. Waits for the right kind of message.
    branching:
      type: message
      branches:
      - pattern: |
          {"message":{"wants":"?wants"}}
        target: deliver
  deliver:
    doc: |
      Decrement the counter and emit a message.
    action:
      interpreter: ecmascript
      source: |
        var remaining = _.bindings["n"] - 1;
        _.bindings["n"] = remaining;
        _.out({serve: _.bindings["?wants"], with: _.bindings["has"], remaining: remaining});
        delete _.bindings["?wants"];
        return _.bindings;
    branching:
      branches:
      - pattern: |
          {"n": 0}
        target: change
      - target: start
  change:
    doc: |
      Insist on water from now on.
    action:
      interpreter: ecmascript
      source: |
        return {n: 1, has: "water"};
    branching:
      branches:
      - target: start