Semmle

Semmle Limited is a British software analytics company known for a product originally called SemmleCode, a static software analysis package. It can be used to find programming bug patterns, to compute software metrics, and to enforce coding conventions. All these tasks can be formulated as queries in an object-oriented query language named QL.

The company is headquartered in Blue Boar Court, Alfred Street, central Oxford, England and customers include Citi, Credit Suisse, NASA and Dell.

Background

Academic

SemmleCode builds on academic research on querying the source of software programs. The first such system was Linton's Omega system, where queries were phrased in QUEL. QUEL did not allow for recursion in queries, making it difficult to inspect hierarchical program structures such as the call graph. The next significant development was therefore the use of logic programming, which does allow such recursive queries, in the XL C++ Browser. The disadvantage of using a full logic programming language is however that it is very difficult to attain acceptable efficiency. The CodeQuest system, developed at the University of Oxford, was the first to exploit the observation that Datalog, a very restrictive version of logic programming, is in the sweet spot between expressive power and efficiency. The QL query language is an object-oriented version of Datalog.