TransformGRanges , a ProxyGRanges
derivative that transforms one or more columns in the element
metadata. The transformation is implemented by the subclass.setTransformGRangesClass(prefix, transform, reverseTransform = NULL, parameters = list(), where = topenv(parent.frame()), ...)GenomicRanges and any parameters as arguments.NULL if
reverse transformation is impossible.setRefClass. The parameter values are
passed as individual arguments to transform and
reverseTransform.TransformGRanges, a class for the storing the parameters is
also defined, and constructors for both classes are assigned into
where.setProxyGRangesClass.