Arbortext Command Language, most-commonly referred to as ACL, is a scripting language for PTC's Arbortext software. Arbortext is an XML and SGML authoring tool. Further information: "Starting With Arbortext's ACL Language - Part 1". Part one of two-part ACL article on StructoredAuthoring.org blog. April 2009.
Some ACL code samples can be found here.
References
Arbortext Command Language Wikipedia(Text) CC BY-SA