While going over Dimitre's new XSLT course, I was wondering about the
following: would it be possible to compile a list of, say, top 10 of the
most used XSLT design patterns?

Something like (unordered as of yet):
- modified identity transform
- fill-in-the-blanks
- aggregate transforms (totals, averages, counts etc)
- sorting
- flat-to-hierarchy
- hierarchy-to-flat
- unparsed text mining (?)
- data merging

Not sure whether each of them can be given a true programming pattern,
and surely, I am missing many obvious cases (any you would like to
add?). I am often of the impression that the modified identity transform
is by far the most widely used, but I can be wrong, perhaps it is
aggregation or fill-in-the-blanks?

It will likely be non-trivial to compile such list without a good query
to search through existing stylesheets and known programming challenges.
But from your experience, what patterns do you encounter most often?

Cheers,

Abel Braaksma
Exselt XSLT 3.0 processor
http://exselt.net