Add option of format (XLS or XLSX )

[jmunene]

When reading the data, currently the package reads as a flat CSV file.
Adding an option to choose whether to read the data in XLS or XLSX format will help in handling of repeats data where the package will create 2 objects, the Main section and the repeats section.

R has packages that read XLS or XLSX formats, to mention just a few;

• xlsx Package
• readxl Package
• xlconnect package
• openxlsx