Thanks again Jim!
For all other interested people: Jim wrote a script that automatically assigns tags to DTP documents. The tags have to follow the @symbol and start in a new line each. You simply select the document, then run the script.
I created a smart (dropbox-)folder that automatically imports new documents to DTP. So now I can create a note, e.g. in Drafts4, quickly add some tags within it (TextExpander!) and save it in that dropbox folder. It gets automatically imported to DTP. All that remains for me to do is select the new items in the Inbox, run the script and move them to my „notes“ group in DTP.
Ideas on automating even that last step are welcome, but it is really not that much of work.
Here is the script:
tell application id “DNtp”
repeat with thisRec in (selection as list) – Processes selected files in DEVONthink Pro / Pro Office
tell thisRec to set tags of thisRec to (tags of thisRec & (paragraphs of (do shell script “grep -e ^\@ " & (quoted form of (path as string) & " | sed ‘s_@__1’”))))
– This scrapes the text pulling the lines that begin with @, then it removes the first occurence of the symbol and adds them to the current Tags of the file
end repeat – Then moves on to the next file, or exits the loop.
end tell