tailrecursion/dataflow

A dataflow library for Clojure

A Dataflow Engine for clojure

This package is a dataflow engine for Clojure modeled loosely on the "Cells" model, but using Clojure Ref's to manage state rather than Agents.

Status

This is here for purely Archival purposes.
You should use javelin.

Usage

(def df
  (build-dataflow [
    ; Source cells are set by the user
    (cell :source fred 1)

    ; Reference other cells by ?name
    (cell greg (+ ?fred ?mary))

    (cell joan (+ ?fred ?mary))

    ; Order does not matter
    (cell :source mary 0)

    (cell joan (* ?fred ?mary))

    ; Multiple joans exist, ?*name returns a collection
    (cell sally (apply + ?*joan))

    ; validators can return exceptions.  ?-name gets the old value
    (cell :validator (when (number? ?-greg)
                    (when (<= ?greg ?-greg)
                        (throwf Exception "Non monotonic"))))
  ]))

(add-cell-watcher (get-cell df 'sally)
                nil
                (fn [key cell o n]
                    (printf "sally changed from %s to %s\n" o n)))

(full-update df)
(update-values df {'fred 1 'mary 1})
(update-values df {'fred 5 'mary 1})
(update-values df {'fred 0 'mary 0}) ; Will throw Non monotonic exception

(get-value df 'fred)
(get-values df 'joan)
(get-value df 'sally)
(get-value df 'greg)

TODO

• lein
• test
• docs