Missing pivot table features

[JanMarvin]

As reference, this is nothing I'm currently working on or have a huge desire to work on. All of this should be possible, but I'd have to research it and at the moment I simply have better things to do.

• adding slicers [WIP] add wb_add_slicers #822
• adding timelines [pt] add wb_add_timeline() #1017
• removing slicers
• modifying slicers
• adding/modifying/removing filters of existing pivot tables
• modifying existing pivot tables
• writing pivot tables into the sheet
• calculating new fields within a pivot table [pt] calculate pivot table field with formula #892
• calculating new items to a pivot table (see above PR892 for details)
• adding or modifying pivot table styles
• filtering pivot table elements (see [Pivot Tables] filtering pivot tables #827)

[JanMarvin]

Thanks so much for reaching out, and I appreciate the kind words! The thing is, researching all the pivot table extensions takes a lot of my time. I would estimate that the time to even get pivot tables working was about a seven day week's worth of work - after my actual rent paying job. Creating pivot tables in Excel, extracting the xml files, trying to recreate the xml files in R, getting some things to work, trying the next ...

But now since pivot tables work, people go to stackoverflow and ask how to add slicers or how to create new values with formulas in pivot tables. I understand that people want super-fast, well-tested, feature-rich software, but at the same time, people often have a tendency to get a little too demanding quickly - especially because R is used a lot in business contexts. And then open source developers are quickly treated as a kind of unpaid technical staff to be bossed around, but if people want all that, maybe they should pay a bunch of full-time developers.

This issue is merely a reminder to guide people to the next time someones asking :)