Perl Support for XML Developing

Mar 10, 1998 by Dale Dougherty

How to Make Perl The Language of Choice for XML

Perl has been the language of choice for anyone doing serious text processing. Now efforts are underway to make Perl the language of choice for those doing “structured” text processing using the Extensible Markup Language (XML).

The XML 1.0 specification was recently (Feb. 10, 1998) released as a recommendation by the World Wide Web Consortium. XML is a subset of SGML (Standard Generalized Markup Language) and it seems to be emerging as a universal syntax for defining non-proprietary document markup and data formats. XML made significant changes to SGML to reflect the nature of the Web and to make it easier to build tools that process XML.

Tim Bray, co-editor of the XML 1.0 specification, has used Perl extensively for huge text processing applications. He had a special interest in seeing a bridge built from Perl to XML – one that would make it simple for programmers to process XML data. So, out of this interest, a small group of developers met at O’Reilly & Associates in Sebastopol, California for a one-day Perl/XML summit. In addition to Tim, those attending the summit were:

• Larry Wall, creator of Perl, and senior developer, O’Reilly & Associates
• Dick Hardt, developer of Perl for Win 32, and Chief Technology Officer, ActiveState Tool Corp.
• Tim O’Reilly, President and CEO, O’Reilly & Associates
• Dale Dougherty, CEO, Songline Studios
• Gina Blaber, Director, Software Products Group, O’Reilly & Associates.

“In the design of XML, we were continuously mindful of the need to enable the fast, efficient creation of scripts and programs for processing XML,” says Tim Bray.

“For many of us in the XML effort, the most important goal is to increase the proportion of the world’s documents stored in open, non-proprietary formats,” Bray continues. “Building slick XML processing into Perl makes the use of such formats more rewarding and helps frustrate the efforts of those who would imprison human knowledge behind the barbed-wire of proprietary file formats.”

“XML is currently perceived as powerful and important, but not particularly easy,” explains Larry Wall. “This makes XML and Perl naturally complementary, since Perl is a language that makes easy things easy to do, and hard things possible.”

One of the first steps that the summit group identified was to get Perl working with Unicode (ISO 10646). Unicode enables code to be easily translated into other languages; XML requires Unicode. Larry Wall will lead the team working on this task.

The next step is figuring out at what level Perl actually provides support for XML: whether it’s built into the language, implemented as a module or a combination of both.

Among the goals set at the meeting were:

• Release a Perl/XML spec in Q3, 1998.
• Establish a mailing list for discussion of Perl and XML developer issues.
• Develop an XML white paper, co-authored by Larry Wall and Tim Bray, to be released this spring.

If you are interested in these efforts, you might want to attend the Perl and XML session at the XML Developer’s Day in Seattle at the The XML Conference on March 27, 1998. Larry Wall and Dick Hardt will be speaking. The Perl Developer Update will also keep track of new announcements.