An old js dsl example

routing.js

jBus.routing = new (function() {

    function lazy(builder) {
        this.builder = builder;
        this.buildWith = function(func) {
            this.builder = func;
        };
        this.value = function() {
            return this.builder();
        };
    }

    var graph = new lazy(function() {
        return new jBusRegistry().buildGraph();
    });
    
    function jBusHandler(type, action) {
        this.type = type;
        this.action = action;

        this.handle = function(msg) {
            this.action(msg);
        };
    }

    function jBusGraph(handlers) {
        this.handlers = handlers;
        this.handlersFor = function(type) {
            var self = this;
            var typedHandlers = [];
            for(var i = 0; i < self.handlers.length; i++) {
                var h = self.handlers[i];
                if(h.type == type) {
                    typedHandlers.push(h);
                }
            }

            return typedHandlers;
        };
    }

    function jBusRegistry() {
        this.handlers = [];
        this.on = function(type, action) {
            this.handlers.push(new jBusHandler(type, action));
        };

        this.buildGraph = function() {
            var self = this;
            return {
                handlers: self.handlers
            };
        };
    }

    return {
        initialize: function(configure) {
            var registry = new jBusRegistry();
            configure.call(registry);

            graph.buildWith(registry.buildGraph);
        },
        handle: function(msg) {
            if(!graph) {
                graph = new jBusRegistry().buildGraph();
            }

            var socketMsg = eval('(' + msg.data + ')');
            var message = eval('(' + socketMsg.Message + ')');

            // handle
            var handlers = graph
                            .value()
                            .handlersFor(socketMsg.Type);
             
             for(var i = 0; i < handlers.length; i++) {
                handlers[i].handle(message);
             }
        }
    };
})();