In this document, we publish the source code of the CPH MPL, Copenhagen metaprogramming library (release 2), which provides a wide variety of metaprograms. We had a strong urge to release this package because

• we find the use of the tools convenient; maybe others also want to use them;
• the tools must be reviewed and used by others to get rid of some hard-to-find errors that are unavoidable for a package of this size; thus, any constructive user feedback would be valuable for us;
• the tools are used in some of our other packages, so the users of these packages will need this package, too;
• the tools have a clear developmental value; they show some shortcomings in the facilities available at the C++ standard library; possibly this will lead to improvements there as well;
• the tools have some pedagogical value; by reading the source code it should be easier for others to write their own metaprograms.

The CPH MPL was developed in parallel with the CPH STL class templates designed for the manipulation of multiple-precision integers. Basically, only tools that were needed by this application were programmed. The reader should have this limitation in mind.

@report{Kat2020aS,
  author = {Jyrki Katajainen},
  title = {Documenting the CPH MPL---release 2---by code},
  type = {CPH STL report},
  number = {2020-1},
  institution = {Department of Computer Science, University of Copenhagen},
  year = {2020},
  pagetotal = {109},
}