Comment by cdhdc

It has been used successfully in production. According to this webpage http://www.infoq.com/articles/dsl-interaction-txl it was used for Y2K analysis and conversions of over 3.5 billion lines at IBM Global Services.

Edit: Better reference paper: http://ftp.qucis.queensu.ca/home/cordy/Papers/TXLSE_IST.pdf