### Recursive map/reduce protocol.
###
### Copyright 2018 Alceste Scalas <alceste.scalas @ imperial.ac.uk>
### Released under the MIT License: https://opensource.org/licenses/MIT

s[mapper]: μ(t)(
             worker1⊕datum(Int) .
             worker2⊕datum(Int) .
             worker3⊕datum(Int) .
             reducer&{
               continue(Int) . t,
               stop . (
                 worker1⊕stop .
                 worker2⊕stop .
                 worker3⊕stop
               )
             }
           ),

s[worker1]: mapper&datum(Int) .
            μ(t)(
              reducer⊕result(Int).
              mapper&{
                datum(Int) . t,
                stop . end
              }
            ),

s[worker2]: mapper&datum(Int) .
            μ(t)(
              reducer⊕result(Int).
              mapper&{
                datum(Int) . t,
                stop . end
              }
            ),

s[worker3]: mapper&datum(Int) .
            μ(t)(
              reducer⊕result(Int).
              mapper&{
                datum(Int) . t,
                stop . end
              }
            ),

s[reducer]: μ(t)(
              worker1&result(Int) .
              worker2&result(Int) .
              worker3&result(Int) .
              mapper⊕{
                continue(Int) . t,
                stop . end
              }
            )