ISO has been working on CTM (Compact Topic Maps syntax) for a while now, but very little has been published about it yet. I got a question about it by email, and decided to blog about it in case others were curious, too.

We already have LTM and AsTMa= as compact textual syntaxes for Topic Maps for people who write topic maps in text editors, or who want to show quick examples in email, conference papers, chat, or elsewhere. The idea is that CTM will be the ISO standard to replace these two proprietary syntaxes, to be published as part 5 of ISO 13250 (ie: as ISO/IEC 13250-5).

You may be wondering why ISO bothers with this if we already have two syntaxes for this that work quite well. The reason is that TMQL is going to have an update part as well, and this part needs to support an INSERT operation. For this some compact textual way to express what is to be inserted is needed, and CTM will be used for this. The reason ISO is creating CTM now is that the TMQL query syntax and the TMCL syntax need to be aligned with this syntax from the start. Developing them all in parallel ensures this.

Exactly what CTM will look like is not yet known, as the standard has not stabilized yet. There have been some initial proposals (see the previous working draft and my Leipzig proposal), but so far none have received anything like a roughly consensual thumbs-up in ISO yet. It's possible that the upcoming Oslo meeting in March will change this. If you want to read more about CTM, the meeting notes from Montréal in August 2005 have more background.