113 lines
3.7 KiB
JavaScript
113 lines
3.7 KiB
JavaScript
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Elm.init = function(module, baseNode) {
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'use strict';
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// defining state needed for an instance of the Elm RTS
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var signalGraph = null;
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var inputs = [];
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var visualModel = null;
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function notify(id, v) {
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var timestep = Date.now();
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var hasListener = false;
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for (var i = inputs.length; i--; ) {
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// must maintain the order of this stmt to avoid having the ||
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// short-circuiting the necessary work of recv
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hasListener = inputs[i].recv(timestep, id, v) || hasListener;
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}
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return hasListener;
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}
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// ensure that baseNode exists and is properly formatted.
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var Render = ElmRuntime.Render.Element;
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if (typeof baseNode === 'undefined') {
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baseNode = Render.newElement('div');
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document.body.appendChild(baseNode);
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baseNode.style.width = window.innerWidth + 'px';
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baseNode.style.height = window.innerHeight + 'px';
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window.addEventListener('resize', function() {
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console.log('resize the base node');
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baseNode.style.width = window.innerWidth + 'px';
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baseNode.style.height = window.innerHeight + 'px';
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}, true);
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var style = Render.newElement('style');
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style.type = 'text/css';
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style.innerHTML = "html,head,body { padding:0; margin:0; }" +
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"body { font-family: calibri, helvetica, arial, sans-serif; }";
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document.head.appendChild(style);
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}
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// create the actuall RTS. Any impure modules will attach themselves to this
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// object. This permits many Elm programs to be embedded per document.
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var elm = { notify: notify, node: baseNode, id: ElmRuntime.guid(), inputs: inputs };
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// evaluate the given module and extract its 'main' value.
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signalGraph = module(elm).main;
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// make sure the signal graph is actually a signal, extract the visual model,
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// and filter out any unused inputs.
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var Signal = Elm.Signal(elm);
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if (!('recv' in signalGraph)) signalGraph = Signal.constant(signalGraph);
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visualModel = signalGraph.value;
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inputs = ElmRuntime.filterDeadInputs(inputs);
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// Add the visualModel to the DOM
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baseNode.appendChild(Render.render(visualModel));
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if ('Window' in elm) {
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var w = baseNode.clientWidth;
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if (w !== elm.Window.dimensions.value._0) {
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notify(elm.Window.dimensions.id,
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Elm.Native.Utils(elm).Tuple2(w, baseNode.clientHeight));
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}
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}
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// set up updates so that the DOM is adjusted as necessary.
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var update = Render.update;
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function domUpdate(value) {
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update(baseNode.firstChild, visualModel, value);
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visualModel = value;
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return value;
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}
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signalGraph = A2(Signal.lift, domUpdate, signalGraph);
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function send(name, value) {
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var e = document.createEvent('Event');
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e.initEvent(name + '_' + elm.id, true, true);
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e.value = value;
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document.dispatchEvent(e);
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}
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function recv(name, handler) {
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document.addEventListener(name + '_' + elm.id, handler);
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}
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return { send : send, recv : recv };
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};
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// Helper function to filter dead inputs. Not specific to initialization.
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ElmRuntime = ElmRuntime || {};
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ElmRuntime.counter = 0;
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ElmRuntime.guid = function() { ++ElmRuntime.counter; return ElmRuntime.counter; }
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ElmRuntime.filterDeadInputs = function() {
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'use strict';
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function isAlive(input) {
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if (!('defaultNumberOfKids' in input)) return true;
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var len = input.kids.length;
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if (len == 0) return false;
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if (len > input.defaultNumberOfKids) return true;
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var alive = false;
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for (var i = len; i--; ) {
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alive = alive || isAlive(input.kids[i]);
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}
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return alive;
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}
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return function filterDeadInputs(inputs) {
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var temp = [];
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for (var i = inputs.length; i--; ) {
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if (isAlive(inputs[i])) temp.push(inputs[i]);
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}
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return temp;
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};
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}();
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