Abstract Syntax Description Language appears to be part of the [[http://www.cs.virginia.edu/zephyr][Zephyr]] project at the University of Virginia (and other places). From their page: * ASDL is designed to describe the tree-like data structures in compilers. Its main goal is to provide interoperability for compiler parts written in different languages. http://www.cs.virginia.edu/zephyr/asdl.html -- Main.MikeVanEmmerik - 26 Feb 2002