How do i get the number of files i have in a disc? (In this case; the 16?)
Is there a doc where we can find all functions and variables available for scripting?
Actually not sure how what you want can be done. $matchedtracks() will AFAIK match the number of tracks, not files, that have at least one file matched, so in your case it will be 11. What you actually want is to know whether a) all files have matches, $eq($matchedtracks(),%_totalalbumtracks%), and b) whether there are more files matched to the release than there are tracks. I am not sure about an existing function that would allow you to do b), but it shouldn’t be hard to implement as a plugin.
Documentation is available on the Picard website for scripting and variables.
As far as I remember $is_complete() was part of some plugin, but your solution is the proper solution for this with the current functionality available by default.
Obviously my memory betrayed me a bit, $is_complete was integrated into Picard, and it was me who actually did that . Please try that function in latest Picard 1.4 development version available from the download page.
It should do what you want: Do not report a release as complete if there are duplicates and it can ignore certain track types ( pregap, video, silence and data tracks, you can choose which should be ignored in the options).