Hidden messages: evaluating the efficiency of code elision in program navigation

Abstract

Text elision is a user interface technique that aims to improve the efficiency of navigating through information by allowing regions of text to be 'folded' into and out of the display. Several researchers have argued that elision interfaces are particularly suited to source code editing because they allow programmers to focus on relevant code regions while suppressing the display of irrelevant information. Elision features are now appearing in commercial systems for software development. There is, however, a lack of empirical evidence of the technique's efficiency. This paper presents an empirical evaluation of source code elision using a Java program editor. The evaluation compared a normal 'flat text' editor with two versions that diminished elided text to levels that were 'just legible' and 'illegible'. Performance was recorded in four tasks involving navigation through programs. Results show that programmers were able to complete their tasks more rapidly when using the elision interfaces, particularly in larger program files. Although several participants indicated a preference for the 'just legible' elision interface, performance was best with illegible elision.

Evaluating a fisheye view of source code

“…The fixed degree of magnification for the source lines in Figure 3(b) causes lines with a high degree of interest, that are far from the focus area, to be suppressed or clipped from the view. Similar approaches were used by Cockburn and Smith [3] and Hornbaek and Frøkjaer [8]. In contrast, our prioritization strategy in Figure 3(a) first allocates space to the lines with high DOI to assure that they are included in the view.…”

“…Navigation tasks from a study of source code elision [3] were used to evaluate the hypothesis that the fisheye view enables the programmer to navigate faster in the source code. We expected that it would be easier to find the information required to solve the task with the Fisheye interface, because there would be no need for scrolling the view.…”

“…An alternative to the fisheye view, source code elision, requires the user to manually fold and unfold blocks of program lines, thus avoiding the issue of defining the focal point. In Jaba [3], for example, methods in Java classes were elided, diminishing the bodies of methods while displaying the method signature lines in normal size. An empirical study by Cockburn and Smith [3] showed that such elision may improve navigation tasks in programming.…”

“…In Jaba [3], for example, methods in Java classes were elided, diminishing the bodies of methods while displaying the method signature lines in normal size. An empirical study by Cockburn and Smith [3] showed that such elision may improve navigation tasks in programming. However, the cost of the user's direct manipulation of the view may in practice prove to outweigh the benefits of elision.…”

Object-focused environments revisited

“…Therefore, IDEs make use of graphical elements which abstract over the raw code, such as code elision or class overview widgets. Code elision is the folding of meaningful portions of code on demand, to hide irrelevant sections of the objects, to aid programmers when reading complex source code files [25]. Similarly, IDEs provide another means of viewing and navigating the composition of classes and packages, in the form of overview widgets, which enable a tree view interaction with the objects, depicted in Figure 1.3(a).…”