loader.js

define(['state', 'scripts'], function (state, scripts) {   
    var allowedVersions = [500, 510, 520, 530, 540, 550];
    
    var getXmlAttribute = function (node, attributeName) {
        var attribute = node.attributes[attributeName];
        if (!attribute) return null;
        return attribute.value;
    };
    
    var loadElementAttributes = function (element, nodes) {
        for (var i = 0; i < nodes.length; i++) {
            if (nodes[i].nodeType !== 1) continue;
            var attributeName = nodes[i].nodeName;
            var attributeValue = nodes[i].textContent; 
            state.set(element, attributeName, attributeValue);
        }
    };
    
    var loaders = {
        'game': function (node) {
            state.create('game');
            var name = getXmlAttribute(node, 'name');
            state.set('game', 'name', name);
            loadElementAttributes('game', node.childNodes);
        },
        'function': function (node) {
            var paramList;
            var parameters = getXmlAttribute(node, 'parameters');
            if (parameters) {
                paramList = parameters.split(/, ?/);
            }
            state.addFunction(getXmlAttribute(node, 'name'),
                scripts.parseScript(node.textContent),
                paramList);
        }
    };
    
    var load = function (data) {
        var parser = new DOMParser();
        var doc = parser.parseFromString(data, 'application/xml');
        var firstNode = 0;
        for (var i = 0; i < doc.childNodes.length; i++) {
            if (doc.childNodes[i].nodeType === 1) {
                firstNode = i;
                break;
            }
        }
        var asl = doc.childNodes[firstNode];
        if (asl.nodeName !== 'asl') {
            throw 'File must begin with an ASL element';
        }
        var versionAttribute = asl.attributes['version'];
        if (!versionAttribute) {
            throw 'No ASL version number found';
        }
        var version = parseInt(versionAttribute.value);
        if (allowedVersions.indexOf(version) === -1) {
            throw 'Unrecognised ASL version number';
        }
        
        for (var i = 1; i < asl.childNodes.length; i++) {
            if (asl.childNodes[i].nodeType !== 1) continue;
            var loader = loaders[asl.childNodes[i].nodeName];
            if (loader) {
                loader(asl.childNodes[i]);
            }
            else {
                console.log('no loader for ' + asl.childNodes[i].nodeName);
            }
        }
        
        state.dump();
    };
    
    return {
        load: load
    };
});