path.js

var Path = {
    'version': "0.8.4.1",
    'map': function (path) {
        if (Path.routes.defined.hasOwnProperty(path)) {
            return Path.routes.defined[path];
        } else {
            return new Path.core.route(path);
        }
    },
    'root': function (path) {
        Path.routes.root = path;
    },
    'rescue': function (fn) {
        Path.routes.rescue = fn;
    },
    'history': {
        'initial': {}, // Empty container for "Initial Popstate" checking variables.
        'pushState': function (state, title, path) {
            if (Path.history.supported) {
                if (Path.dispatch(path)) {
                    history.pushState(state, title, path);
                }
            } else {
                if (Path.history.fallback) {
                    window.location.hash = "#" + path;
                }
            }
        },
        'popState': function (event) {
            var initialPop = !Path.history.initial.popped && location.href == Path.history.initial.URL;
            Path.history.initial.popped = true;
            if (initialPop) return;
            Path.dispatch(document.location.pathname);
        },
        'listen': function (fallback) {
            Path.history.supported = !!(window.history && window.history.pushState);
            Path.history.fallback = fallback;

            if (Path.history.supported) {
                Path.history.initial.popped = ('state' in window.history), Path.history.initial.URL = location.href;
                window.onpopstate = Path.history.popState;
                
                if (window.location.hash === "") {
                    if (Path.routes.root !== null) {
                        Path.history.pushState({}, "", Path.routes.root);
                    }
                }
            } else {
                if (Path.history.fallback) {
                    for (route in Path.routes.defined) {
                        if (route.charAt(0) != "#") {
                            Path.routes.defined["#" + route] = Path.routes.defined[route];
                            Path.routes.defined["#" + route].path = "#" + route;
                        }
                    }
                    Path.listen();
                }
            }
        }
    },
    'match': function (path, parameterize) {
        function matchPathToRoute(path, route) {
            var tokens = route.split('/');
            var re = /\/?([^\/]+)/;
            var isMatch = true;
            var params = {};
            var match, routePart;


            for (;
                  isMatch &&
                  tokens.length &&
                  path.length &&
                  (match = re.exec(path)) ;
                path = path.substring(match[0].length)) {
                var routePart = tokens.shift();
                if (routePart.charAt(0) == ':') {
                    // keep this param
                    params[routePart.substring(1)] = match[1];
                } else if (routePart !== match[1]) {
                    // non-parameterized part, they must match
                    isMatch = false;
                } // else just continue
            }
            return (isMatch && (0 === tokens.length) && (0 === path.length)) ?
                params : false;
        }

        var params = {}, route = null, possible_routes, slice, i, j, compare;
        for (route in Path.routes.defined) {
            if (route !== null && route !== undefined) {
                route = Path.routes.defined[route];
                possible_routes = route.partition();
                for (j = 0; j < possible_routes.length; j++) {
                    slice = possible_routes[j];
                    compare = path;
                    params = matchPathToRoute(compare, slice);
                    if (params) {
                        if (parameterize) {
                            route.params = params;
                        }
                        return route;
                    } else {
                        params = {};
                    }
                }
            }
        }
        return null;
    },
    'dispatch': function (passed_route) {
        var previous_route, matched_route;
        if (Path.routes.current !== passed_route) {
            Path.routes.previous = Path.routes.current;
            Path.routes.current = passed_route;
            matched_route = Path.match(passed_route, true);

            if (Path.routes.previous) {
                previous_route = Path.match(Path.routes.previous);
                if (previous_route !== null && previous_route.do_exit !== null) {
                    previous_route.do_exit();
                }
            }

            if (matched_route !== null) {
                matched_route.run();
                return true;
            } else {
                if (Path.routes.rescue !== null) {
                    Path.routes.rescue();
                }
            }
        }
    },
    'listen': function () {
        var fn = function() { Path.dispatch(window.location.hash); };

        if (window.location.hash === "") {
            if (Path.routes.root !== null) {
                window.location.hash = Path.routes.root;
            }
        }

        // The 'document.documentMode' checks below ensure that PathJS fires the right events
        // even in IE "Quirks Mode".
        if ("onhashchange" in window && (!document.documentMode || document.documentMode >= 8)) {
            window.onhashchange = fn;
        } else {
            setInterval(fn, 50);
        }

        if (window.location.hash !== "") {
            Path.dispatch(window.location.hash);
        }
    },
    'core': {
        'route': function (path) {
            this.path = path;
            this.action = null;
            this.do_enter = [];
            this.do_exit = null;
            this.params = {};
            Path.routes.defined[path] = this;
        }
    },
    'routes': {
        'current': null,
        'root': null,
        'rescue': null,
        'previous': null,
        'defined': {}
    }
};
Path.core.route.prototype = {
    'to': function (fn) {
        this.action = fn;
        return this;
    },
    'enter': function (fns) {
        if (fns instanceof Array) {
            this.do_enter = this.do_enter.concat(fns);
        } else {
            this.do_enter.push(fns);
        }
        return this;
    },
    'exit': function (fn) {
        this.do_exit = fn;
        return this;
    },
    'partition': function () {
        var parts = [], options = [], re = /\(([^}]+?)\)/g, text, i;
        while (text = re.exec(this.path)) {
            parts.push(text[1]);
        }
        options.push(this.path.split("(")[0]);
        for (i = 0; i < parts.length; i++) {
            options.push(options[options.length - 1] + parts[i]);
        }
        return options;
    },
    'run': function () {
        var halt_execution = false, i, result, previous;

        if (Path.routes.defined[this.path].hasOwnProperty("do_enter")) {
            if (Path.routes.defined[this.path].do_enter.length > 0) {
                for (i = 0; i < Path.routes.defined[this.path].do_enter.length; i++) {
                    result = Path.routes.defined[this.path].do_enter[i].apply(this);
                    if (result === false) {
                        halt_execution = true;
                        break;
                    }
                }
            }
        }
        if (!halt_execution) {
            Path.routes.defined[this.path].action(this.params);
        }
    }
};