What is this language, and how to learn it?

It is in the Solidworks Inspection Add-in, Need to know how to program in that language to automate the numbering process for our prints.

Here is the code that is in the Add-in already, need to modify it to work with what we need:

(\\d{1,3}\\.\\s{0,3}.*)|.*|^R\\s{0,2}\\.\\d{1,4}.*|^RUN@.*|(\\.\\d{1,3}\\s{0,3}X\\s{0,3}\\d{1,3}.*)|MARK.*