The first collection page earns the Query primitive: content.Query{Section, Lang}
with Site.Run, newest first, undated after dated, ties broken by key so the same
query always answers in the same order. No cache signature — nothing caches, and a
signature with no consumer is speculation.
Pagination lives in the path (ADR-0028): page one is the bare listing URL,
/page/1/ redirects to it, and a page past the end is 404 rather than an empty page,
because an empty page is a URL that means nothing. `page` is therefore a reserved
segment inside a section, now recorded in content-model.md.
Two kinds of page means two parsed template sets already — base plus the block that
kind defines — which is ADR-0019's per-type shape arriving by need rather than by
anticipation. A head struct is embedded in both Page and List so base.html has one
contract, and theme-contract.md gains the listing fields.
Bundle gains Date, accepting an unquoted YAML date or an RFC 3339 string, since
yaml.v3 hands back time.Time for one and a string for the other.
Evidence: 12 posts → /posts/ shows 10 with rel=next to /posts/page/2/,
/posts/page/2/ shows 3 with rel=prev to /posts/, ordering is post-12 11 10,
/posts/page/1/ 301s to /posts/, /posts/page/9/ is 404, /bn/posts/ is 200.
5.7 KiB
Theme contract
What the engine promises a theme, and the only thing this repository is bound to (ADR-0023). A theme's markup, layout and styling are not the engine's business; a theme's inputs are.
STATUS: partly live. The fields under Live today exist and are gated; everything else is the shape the contract takes when the feature arrives. All of it is engine obligation, not theme instruction — a theme may ignore any of it.
Live today
A bundle page receives:
| Field | Contents |
|---|---|
.Title |
may be empty; a template falls back to .Key rather than failing |
.Lang |
the locale of this variant, always set |
.Key |
the bundle's identity, without language or extension |
.HTML |
the rendered body, already escaped |
.Extra |
every frontmatter key the parser does not name (ADR-0002) |
.Style |
the reference theme's stylesheet, inlined so a bare site root needs no asset route |
.Canonical |
the permalink of the variant actually served — not the URL requested, which differs when the fallback chain supplied another language |
.Alternates |
every language this key exists in, as .Lang and .URL, for hreflang |
Two named templates: base is executed for every page; main is the block each kind of page defines and
a theme redefines. There is one parsed set per kind — bundle and listing today — so two kinds may both
define main without colliding (ADR-0019).
A listing page receives .Title, .Lang, .Canonical, .Style as above, plus:
| Field | Contents |
|---|---|
.Items |
entries on this page: .Title, .Key, .URL, .Date |
.Page, .Pages |
1-based position and total, Pages at least 1 |
.PrevURL, .NextURL |
empty at the ends; newer is prev, because the order is newest first |
The stability rule
Fields and names are added, never renamed or removed. Absence is always legal: a template reading a
field that does not exist gets the zero value and must not crash, and the engine must not make a missing
field fatal at request time (ADR-0002, invariant 1). This is the View-layer freeze from
architecture.md, arriving as soon as a theme exists rather than at Arc 2.
Breaking the contract is not a feature — it is a new contract version, and it needs an ADR.
What the engine provides
| Provides | Detail |
|---|---|
| the page object | known fields plus an Extra bag carrying unknown frontmatter (ADR-0002) |
| the resolved cascade | settings after site → section → bundle resolution (ideas/deferred-decisions.md) |
| queries the page needs | its sequence neighbours, its taxonomy terms, its section's members |
| named template lookup | per-type sets; a theme redefines a named block and inherits the rest (ADR-0019) |
| URLs | every path the engine emits, so a theme never constructs one by hand |
| per-page assets | the styles / scripts frontmatter lists, resolved relative to the bundle |
| chrome strings | looked up by key and language, never hardcoded English in a template |
| validity windows | a template that renders time-dependent output declares one |
Extras view
For a request under a bundle's extras directory (ideas/deferred-decisions.md) the engine additionally provides:
| Field | Contents |
|---|---|
.Extras.Entries |
the tree: Name, Path, URL, RawURL, Kind, Size, IsDir, ModTime |
.Extras.Selected |
nil on the bare listing; otherwise the chosen entry |
.Extras.Selected.HTML |
rendered output for markdown and text kinds; empty otherwise |
.Extras.Selected.RawURL |
always present — for <img src>, <object data>, or a download link |
.Bundle is the parent, so a theme has its title, language and breadcrumb. Selecting an entry is an
ordinary link and a full re-render, so a sidebar-plus-pane layout needs no JavaScript; swapping the pane
client-side is a later enhancement over working markup, never a requirement.
What the engine does not provide
Layout, class names, CSS, client-side behaviour, and any choice about how something looks — including how media is embedded, how a listing is arranged, and whether something appears in a sidebar. Those are theme decisions, and a request touching them is split: a contract extension here, a change there.
The engine also does not provide a component library, a CSS build step, or a JavaScript runtime.
conventions.md holds the output floor the engine itself meets — semantic HTML, zero-JS, every image
carrying width, height and alt — and a theme is expected to stay inside it, but the engine does not
enforce a theme's markup.
The reference theme
The binary embeds a reference theme — templates plus one small stylesheet — so a bare site root renders (ADR-0026). It exists to make this document executable: it implements every field and block named here and nothing else, and a golden-file test through it catches contract regressions before a real theme does.
It is not a design. Legibility only, no branding, no visual opinions, no JavaScript — verify.sh fails on
a <script tag in it. If it starts accumulating taste, it has stopped being a reference.
It demonstrates the contract; it is not the contract. Changing it does not change what a theme may rely on
— which is why verify.sh also fails when it changes without this document changing, since in practice the
two drift together.
Splitting a request
When a feature spans engine and theme, this repo delivers:
- the contract extension — new fields, new named blocks, new queries, new URLs;
- a note stating what a theme must do to use it, precise enough to act on without this conversation;
- embedded defaults updated far enough to prove the extension works.
It does not deliver the theme. Claiming otherwise is the same error as claiming to have migrated content in a site root this repo cannot see.