writeonce/docs/examples/site/CODE-LOGIC.md

site — how it is put together

Written 2026-08-23 with the sample's landing; restructured 2026-08-25 onto the program template's MVC layout (docs/examples/shop), so the two samples now read the same way.

The layout

file	layer	what it owns
types.wo	MODEL	the Chapter @table, the ChapterLink projection, Chapters.links(), and seed_if_empty()
content.wo	MODEL (content)	the ten chapter bodies as fragment-returning functions, plus seed_chapters()
layout/app.wo	VIEW (chrome)	AppShell — the component that fills writeonce-view's Layout — the two named widths, and html_error
layout/header.wo, layout/footer.wo	VIEW (chrome)	the shared nav bar (brand = mark + wordmark) and footer
layout/logo.wo	VIEW (chrome)	the mark as inline SVG, plus the <head> links
install/view.wo, install/controller.wo	VIEW + CONTROLLER	/install — the toolchain guide. Static copy, so InstallPage has no fields
packages/view.wo, packages/controller.wo	VIEW + CONTROLLER	/packages and /packages/:name — the catalogue, its cards, and per-package usage
favicon/controller.wo	CONTROLLER	/favicon.svg — builds its own Resp (image/svg+xml)
home/view.wo	VIEW	HomePage and the homepage's code showcase
home/controller.wo	CONTROLLER	Home — the / handler
chapter/view.wo	VIEW	ChapterNav, ChapterPage
chapter/controller.wo	CONTROLLER	ShowChapter — the /ch/:slug handler
admin/controller.wo	CONTROLLER	AdminEdit — bearer-gated edit, answers a redirect (no view: it redirects)
health/controller.wo	CONTROLLER	Health — the liveness probe (no view: it answers text)
main.wo	BOOTSTRAP	seed, routes, serve. Nothing else
wo.toml	—	the two [deps]: framework (serving) and html (markup)

One feature = one directory = one module, holding that feature's view and its controller together. A module sees its own declarations plus what it uses, so home/ reaching the chapter nav has to say use chapter.

The model stays at the root and is reachable from everywhere: a CLASS crosses module lines without being exported, and only a free fn is module-scoped (WO-E210). That single rule explains the whole layout — Chapter and ChapterLink are classes, so the feature modules just name them; the shared query would have been a free fn, so it is a static fn on Chapters instead. (pub cannot prefix an @table class — recorded gap #1 — but nothing needs it to.)

Decisions that are not obvious from the code

• Chapters are rows, not constants. seed_if_empty() inserts them only when the table answers empty, so a WAL restart keeps admin edits instead of reseeding over them — the sample's own proof of chapter 6's claim. The seed bodies are BUILT with writeonce-view's builders at boot; after that the table is the truth and the builders are never consulted again.
• The seam is enforced by where the query sits. Chapters.links() lives with the MODEL and hands the view a multi ChapterLink — a projection, not a cursor. No component in this sample touches the database, which is what lets ChapterNav be the same component on the homepage and on every chapter page, differing only by current.
• HomePage and ChapterPage hold a Component, not chapter data. The nav arrives as an already-built child component in a slot, so neither page knows what a chapter is. That is content projection — Angular's <ng-content>, with the slot as an ordinary field.
• Two widths, named once. AppShell carries a container field and layout/app.wo exports reading_shell / wide_shell. The Tailwind class strings appear in exactly one place instead of being repeated at every call site.
• Auth is handler-side by doctrine. The framework ships mechanism (bearer_token, constant-time ct_eq); which routes are gated and by which token is policy, so AdminEdit checks its own field. No global middleware — the public pages stay public.
• ok_html is the framework's, beside ok_text/ok_json: a status line plus a content-type is transport, not rendering.
• \$ in chapter code samples. Chapter sources show interpolation (${port}) inside string literals of a language that interpolates — the lexer's \$ escape keeps them literal; code_block() then HTML-escapes the result. This is also why those two samples stay escaped "..." strings rather than becoming raw literals: a raw literal has no escape character, so it cannot spell a literal ${.
• Concat spans lines two ways now. A line ENDING in .. continues on the next (the one newline suppression in the language) — it never works at the START of a line. For markup, prefer the backtick raw literal: real newlines, real double-quoted attributes, source indentation removed at compile time, ${ } raw and {{ }} auto-escaping. The old ".. does not straddle newlines, so build accumulator-style" note is obsolete and was removed.
• The logo is inline SVG, authored once. logo_svg(px) goes in the nav brand and favicon_svg() is served at /favicon.svg — a dark tile with a two-stroke "W", white then accent blue. No asset pipeline, no binary in the repo, and it stays legible at 16px. The <head> link reaches the document through Layout's head slot.
• A raw literal cannot contain a literal {{. The packages page has prose ABOUT {{ }} holes, and writing it directly would have made it a hole; it is written with { entities instead. This is the same limitation the chapter code samples hit with ${, and the reason both doors exist.
• Downloads are the framework's, not the site's. /dl/*path is StaticFiles mounted in main.wo with a 16 MiB ceiling — no controller, because there is no decision to make. WO_DIST says where the tarballs are (default ./dist). The install page offers the GitHub release as primary and this as a mirror, with the .sha256 beside it.
• The supported-systems list is read off the binaries, not off a wish list: file gives the triple, and the highest GLIBC_ symbol version they import gives the libc floor (2.38 today). Overstating support costs a reader an afternoon.
• SITE_HOST picks the interface. Loopback by default — right behind a proxy — with the env var for reaching a dev instance across the LAN. The bound address is printed at startup.
• writeonce-view's sheet is static. Tailwind's class NAMES, one hand-written CSS string inlined per page by page() — self-contained responses, no toolchain; growing the sheet is appending a line in tw_css().

Gate: just site — see scripts/site-accept.sh (11 checks; the restart leg polls /health instead of sleeping, so it does not share web-app-accept's 0.5s boot race).