File import/export for Calligra Sheets -- where to start?

[William Park]

Hi all,

As a way of learning Calligra code, I would like to add a simple file
import/export to Calligra Sheets.  The file format is similar to CSV
format.  Can someone point me to directory/file I should look at?  I see
bunch of files under
    filters/sheets/...
Are they where the import/export routines are located?
-- 
William