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jashmenn/dumb_graph.js

Forked from grayrest/dumb_graph.js
Last active August 29, 2015 14:08
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Revisions

  1. @grayrest grayrest created this gist Oct 11, 2012.
    73 changes: 73 additions & 0 deletions dumb_graph.js
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,73 @@
    function sum (fn, xs) {
    var toRet = 0;
    for (var i = 0, ii = xs.length; i < ii; i++) {
    toRet += fn(xs[i], i, xs);
    }
    return toRet;
    }

    function update(t, o) {
    for (var k in o) {
    t[k] = o[k];
    }
    return t;
    }

    function depGraph(graph) {
    var deps = {};
    for (var k in statsGraph) {
    var fnStr = graph[k].toString();
    var fnArgs = fnStr.slice(fnStr.indexOf('(')+1, fnStr.indexOf(')')).split(/\s*,\s*/);
    deps[k] = fnArgs;
    }
    return deps;
    }

    function satisfyDeps(depsList, results) {
    var acc = [];
    for (var i = 0, ii = depsList.length; i < ii; i++) {
    if (typeof results[depsList[i]] == 'undefined') {
    return false;
    } else {
    acc.push(results[depsList[i]]);
    }
    }
    return acc;
    }

    function eagerCompile(graph) {
    return function(startValue) {
    var deps = depGraph(graph);
    var k = Object.keys(deps);
    var res = update({}, startValue);
    var processing, args, missingDep = true;
    do {
    processing = false;
    for (var i = 0, ii = k.length; i < ii; i++) {
    if (typeof res[k[i]] == 'undefined') {
    if (args = satisfyDeps(deps[k[i]], res)) {
    res[k[i]] = graph[k[i]].apply(res, args);
    processed = true;
    missingDep = false
    }
    }
    }
    if (missingDep) {
    throw 'Missing dependency';
    }
    } while (processing);

    return res;
    }
    }

    var statsGraph = {
    n: function(xs) { return xs.length; },
    m: function(xs, n) { return sum(function(x){ return x; }, xs) / n; },
    m2: function(xs, n) { return sum(function(x){ return x * x; }, xs) / n; },
    v: function(m, m2) { return m2 - (m * m); }
    };

    var stats = eagerCompile(statsGraph);

    console.log(stats({xs: [1, 2, 3, 6]}));