Contributor - spreadsheet upgrade

Description

Excel and Libreoffice Calc XML based formats are not supported by the Scilab spreadsheet module. The current implementation should be extended to support these formats as well as the legacy binary XLS format.

Ideas

Use the current libxml2 and libz Scilab dependency to implement basic support for Excel files. Other external cross-platform libraries can also be used to fully support these formats.

Links

• https://help.scilab.org/docs/6.0.0/en_US/xls_open.html

• https://github.com/PHPOffice/PHPExcel