JSON output

Hello,

In case anyone is playing along at home with my prereleases, this
morning I added a --json option to coffeepot. If the grammar produces a
tree with no mixed-content, this will serialize he results as JSON
instead of XML. (You’ll get an error if the tree produces mixed
content.)

$ coffeepot -g:date.ixml 16 February 2022
<date><day>16</day><month>February</month><year>2022</year></date>

$ coffeepot -g:date.ixml --json 16 February 2022
{"date":{"day":16,"month":"February","year":2022}}

                                        Be seeing you,
                                          norm

--
Norm Tovey-Walsh
Saxonica