The word 'format' is also doing a lot of work
Good point - I'll keep that in mind as I'm writing Developing with QIIME 2.
All of the points you mention are correct. I'll provide a little bit of clarification on some (if I don't mention one it's b/c I have nothing to add to your description).
I can also use data types that are "Formats" in the QIIME sense
Yes, exactly - these are useful when you want to process a file within your action (e.g., iterate over the lines in a fastq file, as in your example).
I can also use QIIME "primitive types"... maybe this is relevant only to function inputs that come in via action 'parameters' and not those that come in via action 'inputs'
Yes, exactly. That's a distinction between 'parameters' and 'inputs': parameters use primitive types while inputs are always artifacts and therefore have semantic types associated with them.
I CANNOT use (data?) types from the python
typinglibrary
Correct. I chatted with @ebolyen about this and his perspective is that typing was changing a lot when we were working on this, so didn't prioritize it then, and it hasn't surfaced as a priority since it's stabilizing.
I am grateful to the QIIME team for all the support you folks provide!
Thank you!