This is for those who are not interested in using Notepad++ and prefer to use Geany. For those who are unfamiliar with Geany, Geany is considered an integrated development environment. It has many features that Notepad++ has (e.g. auto-complete, syntax highlighting, tabbed interface, etc) and perhaps a few other useful features that Notepad++ lacks, and it is cross-platform (though it may be a bit more complex to install on a Mac).
For auto-complete and other suggestive features Geany uses its tags system to accomplish this. To make our work easier for us, we'll simply add the HPL2 functions list to an already existing supported language: the C language. This is done automatically when Geany reads our .tags file. In this way we can just tell Geany to assume that all *.hps files are C++ files, which would also trigger C++ syntax-highlighting and symbols listing for all .hps files.
Now the next time you start Geany your .hps files will provide the same, if not more, satisfaction as it may have in Notepad++.
For those who have trouble following written instructions and want to see it done visually: http://www.youtube.com/watch?v=JeOG53Zapx8