XML Hacks

Create Well-Formed XML with Minimal Manual Tagging Using an SGML Parser

Convert minimal markup into XML with James Clark’s SP.

The problem of converting plain text into basic, well-formed XML occurs over and over again in XML processing. As a general rule, I like to get data into XML as quickly as possible and leave it in XML for as long as possible (preferably forever). The sooner I can get data into XML, the sooner I can bring all my XML-processing tools and knowledge to bear on the data-processing challenges.

When the volume of markup to be created is small, hand-editing using one-off text editor macros is a powerful technique. For higher volumes of markup, a custom program is often the best way to go—Python, Ruby, and Perl, for example, all excel at this sort of work.

Sometimes, the quickest way to get data into XML is by combining judicious use of hand-edits and automatic addition of the markup required using an SGML parser. XML is a subset of a much larger markup technology standard known as SGML (ISO 8879:1986), which has been an international standard since 1986. SGML provides a variety of mechanisms, not found in XML, to minimize the amount of tagging required in documents. Collectively, these techniques are known as markup minimization features. By using an SGML parser to process text, it is possible to take advantage of the tag minimization features to automatically add markup and help create well-formed XML documents.

In these examples, we will use James Clark’s SP ...