SHOPPER: Interpreter for a High-level Web Services Language

Keywords: web service composition, interpreters, OWL, LTML, Lisp

Abstract: We have been working on the POIROT project as part of DARPA’s Integrated Learning program. POIROT is a large research program that aims to integrate multiple systems for learning workflows whose building blocks are semantic web services. These semantic web services are marked up in the Learnable Task Modeling Language (LTML). LTML (McDermott et al. 2008) is a radically composable web service markup and planning language with an s-expression syntax that extends both OWL-S (Martin et al. 2004), the W3C language for semantic web service markup, and the standard planning language PDDL (PDDL Resources). We have developed SHOPPER, a Common Lisp-based interpreter for the LTML language that is able to interpret unified LTML workflows, building and maintaining a complex state model based on information gathered from execution of semantic web services through the OWL Virtual Machine (OVM).