Display Condensation of Program Text

In interactive systems that must display the text of programs, the size of the program is usually much larger than the capacity of the screen. While the obvious strategy is to simply choose k contiguous lines for display in a k-line window, in some cases it is useful to be able to represent m lines in a k-line window, where m > k, by "condensing" portions of the text. This paper is concerned with alternative strategies for controlling such condensation.