Templating processor

[zouharvi]

In jq one can write the following (complex) query jq '[.[] | {message: .commit.message, name: .commit.committer.name, parents: [.parents[].html_url]}]'. I find this templating quite intuitive and useful but at the same time it seems like there's a lot of work behind this (mostly the parsing).

Currently rjp is based around simple operations and piping multiple rjp calls together so I'm not sure that this would even fit into this schema. If it was implemented, it would replace extract, rename and select.