Dependency graph iteration. (Part of lib to come soon)

graph.clj

(defn iterate
  ([graph]
    (iterate graph {}))
  ([graph state]
    (iterate graph state
             (->> graph
               :topo-sort
               (remove nil?)
               first
               fnk->key)))
  ([graph state start-key]
    (let [start-fn (key->fnk graph start-key)
          dependents (deps/transitive-dependents graph start-fn)
          deps (conj (set (mapcat (partial deps/transitive-dependencies graph)
                                  (conj dependents start-fn )))
                     start-fn)
          calc? (conj (union deps dependents) start-fn)
          calc-topo (filter calc? (:topo-sort graph))]
      (-> state
        (iterate* calc-topo update-deps deps)
        (iterate* calc-topo update-dependents dependents)))))

sample.clj

(def g
  {:a 1
   :d/b 2
   :b/a (fnk [a] (* a 7))
   :x (fnk [b/a [d/b 2] [c 3]] (+ b/a d/b c))})

(def cg (compile-graph g))

(iterate cg)
; => {:x 12, :b/a 7, :d/b 2, :a 1}

(iterate cg {:a 7 :x 15} :a)
; => {:d/b 2, :b/a 49, :x 54, :a 7}

(iterate cg {:b/a 11 :a 7 :x 15} :x)
; => {:d/b 2, :x 15, :a 7, :b/a 11}

visualized.svg

<?xml version="1.0" encoding="UTF-8" standalone="no"?><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" contentScriptType="text/ecmascript" width="610" zoomAndPan="magnify" contentStyleType="text/css" height="110" preserveAspectRatio="xMidYMid meet" overflow="visible" version="1.0"><defs><marker refX="10" refY="5" markerUnits="strokeWidth" orient="auto" id="lacij-end-arrow-marker" markerHeight="10" viewBox="0 0 10 10" preserveAspectRatio="xMidYMid meet" markerWidth="14"><polyline points="0,0 10,5 0,10 1,5"/></marker></defs><g id="graph0"><g><g><path style=" stroke: #000000;  stroke-width: 1; " d=" M505.0,55.0 L305.0,85.0 M305.0,85.0 Z"/><line y2="85.0" marker-end="url(#lacij-end-arrow-marker)" style=" stroke: #000000;  stroke-width: 1; " x1="305.0" x2="105.0" y1="85.0"/></g><text x="305.0" y="70.0" style=" dominant-baseline: central; " text-anchor="middle"/></g><g id=":x-:b/a"><line y2="25.0" marker-end="url(#lacij-end-arrow-marker)" style=" stroke: #000000;  stroke-width: 1; " x1="505.0" x2="355.0" y1="35.0"/></g><g id=":b/a-:a"><line y2="25.0" marker-end="url(#lacij-end-arrow-marker)" style=" stroke: #000000;  stroke-width: 1; " x1="255.0" x2="105.0" y1="25.0"/></g><g id="x" transform="translate(505.0, 35.0)"><rect style=" fill: white;  stroke: black; " width="100" height="40"/><text x="50" font-size="12" y="20" style=" dominant-baseline: central; " text-anchor="middle">:x</text></g><g id="a" transform="translate(5.0, 5.0)"><rect style=" fill: white;  stroke: black; " width="100" height="40"/><text x="50" font-size="12" y="20" style=" dominant-baseline: central; " text-anchor="middle">:a</text></g><g id="b" transform="translate(5.0, 65.0)"><rect style=" fill: white;  stroke: black; " width="100" height="40"/><text x="50" font-size="12" y="20" style=" dominant-baseline: central; " text-anchor="middle">:d/b</text></g><g id="a" transform="translate(255.0, 5.0)"><rect style=" fill: white;  stroke: black; " width="100" height="40"/><text x="50" font-size="12" y="20" style=" dominant-baseline: central; " text-anchor="middle">:b/a</text></g></g></svg>

Now with cached :topo-sort in compile-graph. (Part of lib to come soon)