🛠 Retrofitting a book drafted before this track

Status: workflow, part of Write a book.

Written for someone whose chapters already exist, written without an outline. Assumed: the chapters sit in one directory under content/drafts/. Not covered here: the steps after the outline is signed, which are the same as for any book (step 3 on).

A book whose chapters already exist can be brought under the track without rewriting a word. You derive the outline from the book:

1. Take the parts and their chapter numbering from whatever table of contents the book already has.
2. Take each chapter's title from that chapter's own # heading (what the prose says, not the table of contents' paraphrase).
3. Make each unit id the chapter's filename stem, so unit accept finds the prose where it already lives.

One chapter is then one unit: a #### section whose id is the filename, under a ### chapter entry that carries the same title. The chapter heading stays inside the unit file, so book.tex emits \part and \input and lets the fragment's own \chapter{} supply the title; emitting one here as well would print every title twice.

Say in the spec that the outline was retrofitted, and from what. A sign-off records a person's decision; one recorded on an outline nobody has read is a record of the wrong thing.

A retrofitted book can take front and back matter like any other: add ## Front matter {#front} and ## Back matter {#back} to its outline (the reserved parts). Until it does, it assembles as it always has.