Calypso : a visual language for data structures programming

Data structures are more easily understood when they are presented visually rather than textually. We have developed a system, Calypso, to allow the visual definition of data structures programs using pictorial pattern/action pairs in an imperative setting. We present several examples including rebalancing an AVL tree and sorting an array using the Quicksort algorithm. These examples demonstrate the superiority of this visually based approach over textual specifications. Calypso is based on a general framework for building and combining visual notations in various domains. This framework permits Calypso to be easily extended with new data structures and abstractions

A visual language for data structures programming

Data structures are more easily understood when they are presented visually rather than textually. We have developed a system, Calypso, to allow the visual definition of data structures programs using pictorial pattern/action pairs in an imperative setting. We present several examples including rebalancing an AVL tree and sorting an array using the Quicksort algorithm. These examples demonstrate the superiority of this visually based approach over textual specifications. Calypso is based on a general framework for building and combining visual notations in various domains. This framework permits Calypso to be easily extended with new data structures and abstractions

Generalizing abstractions in form-based visual programming languages : from direct manipulation to static representation

We believe concreteness, direct manipulation and responsiveness in a visual programming language increase its usefulness. However, these characteristics present a challenge in generalizing programs for reuse, especially when concrete examples are used as one way of achieving concreteness. In this thesis, we present a technique to solve this problem by deriving generality automatically through the analysis of logical relationships among concrete program entities from the perspective of a particular computational goal. Use of this technique allows a fully general form-based program with reusable abstractions to be derived from one that was specified in terms of concrete examples and direct manipulation. Also addressed in this thesis is how to statically represent the generalized programs. In general, we address how to design better static representations. A weakness of many interactive visual programming languages is their static representations. Lack of an adequate static representation places a heavy cognitive burden on a VPL's programmers, because they must remember potentially long dynamic sequences of screen displays in order to understand a previously-written program. However, although this problem is widely acknowledged, research on how to design better static representations for interactive VPLs is still in its infancy. Building upon the cognitive dimensions developed for programming languages by cognitive psychologists Green and others, we have developed a set of concrete benchmarks for VPL designers to use when designing new static representations. These benchmarks provide design-time information that can be used to improve a VPL's static representation

Visual programming using graphics, relations, and classes

Visual programming techniques have proven successful within limited domains. However, little progress has been made in using graphics to support "real-world" programming. The GRClass system provides a solution by combining Graphics, Relations, and Classes to provide a visual interface for programming graph data structures within an object-oriented framework. This is done by extending the object-oriented model with inter-object relations. These relations are then used to directly implement the conceptual model of the graph data structures. Within the GRClass framework, data structures are objects that maintain relation tables. These relations and the objects participating in the relations constitute the form of the data structure. A graphical notation is used to specify the possible relations and to manipulate the relation graph. GRClass is implemented within the Andrew Toolkit programming environmentThis thesis discusses the motivation for visual programming languages and the GRClass language in particular, presents examples of data structures programmed using GRClass, discusses the implementation of the user interface and code generator, and finally presents some topics for future research.U of I OnlyETDs are only available to UIUC Users without author permissio