lua-cref

Base-class Cref handles source-references in utrace-format as
selections.

Selections are sub-sets of probes that by the child-classes
permits handling groups of probes in unison. Sub-selections are
usually filtered from the full set using either regexp matching,
Lua native table selection, indexes or Cref own index-range
selection.

Sub-selections can also be grown enabling composing resulting
selections of much greater complexity than the primitives mentioned
alone can.

The child-classes Log and Trace are part of the following projects:

* https://gitlab.com/mambrus/utrace.git
* https://gitlab.com/mambrus/tplog.git

However usage is not limited to these, as long as format and
pre-requisites are the same.