Restructure fields

Every pairing is a rename. The left side says where the value goes. The right side says where it comes from. Both are JSON Pointers.

To flatten a nested input:

/title: /book/title
/author: /book/author/name
/year: { source: /book/published, as: number }

{ "book": { "title": "On Mapping", "author": { "name": "Hopper" }, "published": "1998" } }

becomes:

{ "title": "On Mapping", "author": "Hopper", "year": 1998 }

To nest a flat input, point the other way:

/book/title: /title
/book/author/name: /author

{ "title": "On Mapping", "author": "Hopper" }

becomes:

{ "book": { "title": "On Mapping", "author": { "name": "Hopper" } } }

Intermediate containers appear as needed. You never declare them.