Comparing Visual Web Wrapper Generators: A Formal Analysis

Title: Comparing Visual Web Wrapper Generators: A Formal Analysis

Abstract: This research compares and analyzes the expressive power of Elog, a visual web wrapper language used in the Lixto system, to other practical visual wrapper languages. The study finds that Elog is more expressive than other languages, making it a powerful tool for extracting and manipulating data from web pages.

Main Research Question: How does Elog compare to other visual web wrapper languages in terms of expressive power and functionality?

Methodology: The research team studied the core fragment of Elog and formally compared it to other wrapping languages proposed in the literature. They used a formal language theory approach to analyze the expressiveness of Elog and other languages.

Results: The study found that Elog is more expressive than other languages, as it can produce hierarchically structured results and represent complex nested structures. The research team also found that Elog is strictly less expressive than other languages, such as regular path queries with nesting and HEL, a wrapping language used in the W4F framework.

Implications: The findings of this research have significant implications for the field of web wrapper languages. Elog's superior expressiveness makes it a more powerful tool for data extraction and manipulation. The comparison with other languages provides a better understanding of the capabilities and limitations of different wrapper languages.

Keywords: Elog, visual web wrapper languages, formal comparison, expressive power, web data extraction

Link to Article: https://arxiv.org/abs/0310012v1 Authors: arXiv ID: 0310012v1