dialog

Dialog boxes that collect parameters for commands often create ephemeral, unnatural interruptions of a program's normal execution flow, encouraging the user to complete the dialog box as quickly as possible in order for the program to process that command. In this paper we examine the idea of turning the act of collecting parameters from a user into a first class object called a user interface continuation. Programs can create user interface continuations by specifying what information is to be collected from the user and supplying a callback (i.e., a continuation) to be notified with the collected information. A partially completed user interface continuation can be saved as a new command, much as currying and partially evaluating a function with a set of parameters produces a new function. Furthermore, user interface continuations, like other continuation-passing paradigms, can be used to allow program execution to continue uninterrupted while the user determines a command's parameters at his or her leisure.

Tracking both hands in free-space with accompanying speech input can augment the user's ability to communicate with computers. This paper discusses the kinds of situations which call for two-handed input and not just the single hand, and reports a prototype in which two-handed gestures serve to input concepts, both static and dynamic, manipulate displayed items, and specify actions to be taken. Future directions include enlargement of the vocabulary of two-handed “coverbal” gestures and the modulation by gaze of gestural intent.