1. A method for presenting to a user of a software application a user interface permitting the user to select an object associated with the application, the method comprising: providing a first set of declarative-language instructions having a plurality of data structures, including a first data structure storing a plurality of items of first data, each item of first data representing a corresponding user-selectable object presentable to the user via the user interface, wherein selection by the user via the user interface of a particular user-selectable object accesses one or more other user-selectable objects or a resource, or both, associated with the object selected by the user, a second data structure storing items of second data hierarchically associated with the first data structure, each item of second data representing a corresponding action to be taken upon user selection of a particular user-selectable object via the user interface, and a third data structure storing items of third data, each being hierarchically associated with a corresponding first data structure or second data structure or both, wherein the items of third data include references to locations of other user-selectable objects or resources to be accessed by selection of objects corresponding to items of first data; providing a second set of declarative-language instructions including a plurality of sets of computer-executable instructions, wherein each set corresponds to an action represented by a particular item of second data and is configured to accept items of third data as one or more arguments used in executing the instructions; and at runtime of the software application, presenting to a user via the user interface a first selection of items comprising user-selectable objects corresponding to respective items of first data; receiving a user selection of a user-selectable object from the first selection; identifying the selected user-selectable object as a currently-selected object, the currently-selected object being a first placeholder that is not directly coupled with particular functionality; identifying the item of second data representing the corresponding action to be taken upon user selection of the currently-selected object; identifying the set of computer-executable instructions corresponding to the action; identifying one or more items of third data associated with the currently-selected object; executing the identified set of computer-executable instructions using as one or more arguments as location references in the one or more identified items of third data, the one or more arguments collectively being a second placeholder that is not directly coupled with particular functionality wherein execution of the identified set of computer-executable instructions indirectly accesses information associated with one or more other user-selectable objects associated with the currently-selected object or one or more resources associated with the currently-selected object or both; using the information accessed by execution of the identified set of computer-executable instructions to identify a second selection of user-selectable items comprising either one or more of the other user-selectable objects or one or more resources or both, associated with the currently-selected object; and presenting the second selection to the user via the user interface so that the second selection of user-selectable items is dynamically triggered via runtime indirection responsively to the first and second placeholders.