var async = {

    error: function (error) {
        return {
            run: function (callback) {
                callback({ error: error });
            }
        }
    },

    _return: function (arg) {
        return {
            run: function (callback) {
                callback({ result: arg });
            }
        }
    },

    getIdentity: function (v) {
        return _return(v);
    },

    fmap: function (asyncValue, f) {

        return {

            run: function (callback) {

                asyncValue.run(function (callbackResult) {

                    if (callbackResult.result != undefined) {

                        callback({ result: f(callbackResult.result) });

                    } else {
                        callback(callbackResult);
                    }
                });
            }
        }
    },

    bind: function (asyncValue, f) {

        return {

            run: function (callback) {

                asyncValue.run(function (callbackResult) {

                    if (callbackResult.result != undefined) {

                        callback(f(callbackResult.result));

                    } else {
                        callback(callbackResult);
                    }
                });
            }
        }
    },

    ajax: function (args) {

        return {
            run: function (callback) {

                $.ajax({
                    type: args.type,
                    url: args.url,
                    data: args.data,
                    contentType: args.contentType,
                    dataType: args.dataType,
                    success: function (data, success, failure) {
                        callback({ result: data });
                    },
                    error: function (xhr, status, error) {
                        callback({ error: error });
                    }
                });
            }
        }
    }
};