2.3 Mutation Objects

SEL provides a variety of operations that apply mutations to modify code. These mutations are represented as sel:mutation objects.

See the Software Evolution Library Index for full API documentation. We provide a brief outline here.

New sel:mutation subclasses should derive from the most-relevant base class. To define a new mutation from an existing base class, use

(define-mutation new-mutation (base-mutation)
  ())

The mutation may be initialized with two functions; a targeter and picker. The targeter is a function which, given a software object, returns a list of mutation targets; this function defaults to sel:pick-bad. The picker is a function which, given a software object, returns a random mutation target; this function defaults to a random element returned by sel:pick-bad.

After creating a software object and a mutation, use the sel:apply-mutation method to create a new mutant.