The Visitor pattern wraps associated operations that are performed on the elements of an object structure into a separate object. It allows the software designer to define new kinds of operations over the object structure without changing the classes of this structure. But a well-known drawback of this standard Visitor structure is that extending the object structure is hard. This paper present...

Design patterns have been developed to cope with the vast space of possible different designs within object-oriented systems. One of those classic patterns is the Visitor Pattern that is used for representing an operation to be performed on the elements of an object structure. We present a mapping from the Visitor Pattern to a grammar that defines the set of visit sequences that can be performe...

In object-oriented programming the visitor design pattern allows for the addition of new operations on a data hierarchy, but lends itself to scattered traversal code and makes visitors difficult to combine. Previous attempts to solve these issues have separated traversal code from the data structure but still face a lack of modularity in visitor computation making it difficult– if not impossibl...

The behavior of visitors browsing in a web site offers a lot of information about their requirements and the way they use the respective site. Analyzing such behavior can provide the necessary information in order to improve the web site’s structure. The literature contains already several suggestions on how to characterize web site usage and to identify the respective visitor requirements base...

In object-oriented languages, the Visitor pattern can be used to traverse tree-like data structures: a visitor object contains some operations, and the data structure objects allow themselves to be traversed by accepting visitors. In the polymorphic lambda calculus (System F), tree-like data structures can be encoded as polymorphic higher-order functions. In this paper, we reconstruct the Visit...

this study compares differences between japan and austria as regarding outdoor activities. we conducted a survey with respect to the utility patterns of kairakuen garden in mito city, ibaraki prefecture, which is one of the three major historical gardens in japan noted for its beauty. this paper compares the results of our survey with a study of the recreational and spatial utility of the hist...

Traversing and transforming abstract syntax trees that involve name binding is notoriously difficult to do in a correct, concise, modular, customizable manner. We address this problem in the setting of OCaml, a functional programming language equipped with powerful object-oriented features. We use visitor classes as partial, composable descriptions of the operations that we wish to perform on a...

This evaluation project accessed visitor interaction with the Materials Wall, part of a set of prototypes based around Nanotechnology created for MSI. The Material Wall consists of nine stations that each detail a different material. At each station there is a short interactive experiment for the visitor to do, brief (one or two sentence) instructions, an image and a short text that describe us...

Design patterns are well-known couples of problems-solutions for software engineering. By nature, they often lack support from languages and this further complicates the study of their composition in the code. Aspect-oriented languages provide new mechanisms for modularization, which can help to improve design patterns implementation. (Hannemann et al., 2002) is the first extensive study of pat...