Use (flat) ODS spreadsheet format

[mayeulk]

I would suggest to use the flat ODS spreadsheet format. This can be used in addition to .csv or .xlsx.
ODS is the OpenDocument Spreadsheet format of LibreOffice Calc; in short, .ods files are zipped XML files.
Flat ODS is the same standard; except the "compression" algorithm is flat: meaning, uncompressed.

Flat ODS is more convenient than CSV: it opens right away in a spreadsheet software; column widht and types are preserved, as well as formatting...
Flat ODS is more convenient than XLSX: the result is readable by human, it is a 100% opensource technology.
Flat ODS is more convenient than ODS: being plain text, git knows how to make diffs of them; see a sample here; this is why LibreOffice created the flat format; see "LibreOffice and Version control".

Flat ODS files can be named .fods or .ods; they will be opened by Calc and Excel.

readODS::write_fods() supports writing in flat ods.

Based on code in #14, below is a sample code to write a flat ODS file:

readODS::write_fods(spdx_licenses_2_df, 
                    path = "spdx_licenses.fods",
                    row_names = FALSE # the default anyway
                    )

Another advantage of write_fods (and of write_ods) is the support of sheets within a single spreadsheet document.
This would allow, for instance, to store the content of the README in a additional sheet, within the same document.