KVStore.rho

new makeKVStore, stdout(`rho:io:stdout`) in {

  // User call to make a new key-value store
  contract makeKVStore(return) = {

    new storeCh, this in {

      // Give back reference to the created KVstore
      return!(*this) |

      // Initialize with empty store
      storeCh!(Nil) |

      // Put new record
      // contract @(*this, "put")(@key, @value) // alternative syntax. Homework: characterize the performance, phlo cost
      contract this(@"put", key, @value) = {
        for (@oldStore <- storeCh) {
          stdout!("putting a value in") |
          // TODO err if already there
          storeCh!(oldStore | key!(value))
        }
      } |

      // Get existing records out
      contract this(@"get", @key, return) = {
        // Equal mean use the same key as above
        stdout!("In the get method") |

        for(@{ @=key!(value) | rest } <- storeCh) { // Would be better to use peek here Thank Jeremy :)
          storeCh!(@key!(value) | rest) |
          return!(value) // Actually send back the looked up result :)
        }
      }
      |
      contract this(@"lookup", @value, return) = {
        // Equal mean use the same key as above
        stdout!("In the lookup method") |

        for(@{ @key!(=value) | rest } <- storeCh) { // Would be better to use peek here Thank Jeremy :)
          storeCh!(@key!(value) | rest) |
          return!(key) // Actually send back the looked up result :)
        }
      }

      // Update an existing record
      //TODO if we have time
    }
  } |

  // States and capitals use case
  new ack, ack1 in {
    stdout!("In main program") |
    makeKVStore!(*ack) |

    for (statesAndCapitals <- ack) {
      stdout!("received states and capitals store") |
      statesAndCapitals!("put", "Ohio", "Columbus") |
      statesAndCapitals!("put", "Florida", "Tallahassee") |
      statesAndCapitals!("put", "California", "Sacramento") |
      statesAndCapitals!("put", "Georgia", "Atlanta") |

      statesAndCapitals!("get", "Florida", *ack) |
      for (@capital <- ack) {
        stdout!("The capital was " ++ capital)
      }
      |
      statesAndCapitals!("lookup", "Tallahassee", *ack1) |
      for (@state <- ack1) {
        stdout!("The state was " ++ state)
      }

    }
  }
}

// KV Store should look like this
// @"Ohio"!("Columbus") | @"California"!("Sacramento") | @"Florida"!("Tallahassee")