-/*
- Attempt to open the file called FILENAME as a spreadsheet.
- It is not known a priori, what type of spreadsheet FILENAME is, or
- even if it is a spreadsheet at all.
- If it fails to open, then it will return NULL without any error or
- warning messages.
- */
-struct spreadsheet * spreadsheet_open (const char *filename);
-void spreadsheet_close (struct spreadsheet *);