23. An interface for a computer system, comprising: an input operable by a user; a display readable by the user; a grammar defining a language of allowable input strings; a processor coupled to said input, display, and grammar, wherein said processor determines, based on any current partial input strings, all valid next entries according to said grammar, and allows the user to enter in said input only entries which are valid next entries.
23. An interface for a computer system, comprising: an input operable by a user; a display readable by the user; a grammar defining a language of allowable input strings; a processor coupled to said input, display, and grammar, wherein said processor determines, based on any current partial input strings, all valid next entries according to said grammar, and allows the user to enter in said input only entries which are valid next entries. 24. The interface of claim 23, wherein the grammar is a syntactically constrained grammar.