Parser and Writer classes to map from and to file formats

This chapter explains how the Parser and Writer classes in Poio API work. You will learn how to write your own parsers and writers to support a custom file format. Poio API already support a lot of file formats out of the box, which are explained in the following sections. In any case the parser class is used by a general Converter class to map the file format onto a GrAF object. The user may then modify the GrAF object and write back the changes to any of the supported file format (or a custom format, if you implemented a writer). The following Python code demonstrates how one file format can be convert to another one with support of an existing parser and writer class:

parser = poioapi.io.wikipedia_extractor.Parser("Wikipedia.xml")
writer = poioapi.io.graf.Writer()

converter = poioapi.io.graf.GrAFConverter(parser, writer)
converter.parse()
converter.write("Wikipedia.hdr")

This code parses from the XML output of the Wikipedia Extractor and writes the content as GrAF files.

Contents

• How to write a Parser/Writer for a new file format
  • Example: A simple parser based on static data
• Spreadsheet to GrAF conversion
  • The data in Excel
  • Export the data
  • The implementation of the parser
  • How to use the parser to convert to GrAF-XML