Type: board_group

A board_group is a homepage / overview page that previews several referenced sub-containers at once. Each referenced container is rendered as a Board-style card (title + own desc-as-markdown + first N children as deep-link rows) with a trailing “View all →” link when there are more entries than the preview cap. Rendering lives in src/content/board_group.rs.

Compared to board_list: a board_group’s sections are real sub-folders (each section slug must be a child directory with its own ctx.json). A board_list’s sections are virtual labels.

Rendering style

For each section slug in content, the page renders one render_board_card(...) (from src/content/board.rs) using the section’s own Header for the card title and markdown desc, the section’s first preview_count children as rows, and view_all_href = Some("<slug>/") if the section has more children than the preview window.

Each child row in a board_group card uses the deep-link prefix <section_slug>/, so clicking a row jumps directly to /<section_slug>/<leaf_slug>/ — skipping the intermediate section index.

An optional banner image is rendered at the very top of the page (above all section cards) using the resolved language:

<img src="<banner_url>" class="img-fluid rounded mb-4" alt=""/>

ctx.json shape

{
    "type": "board_group",
    "name": {
        "en": "FDS",
        "ja": "FDS",
        "zh": "FDS"
    },
    "desc": {
        "en": "FDS overview — what we publish and where to find it."
    },
    "banner": {
        "en": "/images/banner_en.png",
        "ja": "/images/banner_ja.png"
    },
    "preview_count": 3,
    "content": [
        "policies",
        "cooperation",
        "news",
        "doc"
    ]
}

Field reference

content semantics

For board_group, content is — like board and list — a flat array of slug strings, parsed by the same parse_slug_list helper. Each slug must be a child sub-folder. The section title, desc, and preview rows are all derived from that child’s ctx.json.

This is the key difference from board_list, where content is an array of {name, items} objects and sections do not correspond to sub-folders.

Render flow

1. BoardGroup::read(path) reads ctx.json, builds the Header, the banner: OptionLangDict, the slug list, and preview_count.
2. BoardGroup::render writes the banner (if set), then for each section slug:
   • Loads the section’s ctx.json and Header (or Header::fallback(slug)).
   • Reads the section’s own content list (the section’s children), takes the first min(preview_count, total) entries, and resolves each to a (slug, Header, folder) triple.
   • Sets href_prefix = "<section_slug>/" so each row’s <a href> becomes <section_slug>/<leaf_slug>/.
   • Sets view_all_href = Some("<section_slug>/") if and only if total > preview_n, producing a trailing “View all →” link.
   • Calls render_board_card(...) to render the section card.

Editor capabilities

The current editor surface targets the leaf-board case more than the overview case; for board_group editing typically means editing the referenced section’s own ctx.json (rename, icon, desc) and adjusting the content slug list on the group itself. There is no per-section override on the group: a section card’s title, desc, and icon all come from the section’s own Header.

Save

board_group uses Header::write_into for the metadata block. Saving preserves banner (an OptionLangDict — drops to disk if empty), the slug list, and preview_count. The same rebuild-from-scratch pattern is used so that clearing icon / desc / banner actually disappears from disk.

Gotchas

• A board_group deep-links from its overview rows straight to leaves (/<section_slug>/<leaf_slug>/), bypassing the section index. Don’t rely on the section page being visited first — it is not.
• preview_count only filters how many rows are shown in the card; the full list is still reachable via the “View all →” link.
• A section slug must point at a sub-folder; if its ctx.json is missing, the section card still renders, but with Header::fallback(slug) (slug as title, no desc, no icon, no children). This is intentional — a broken link stays visible rather than vanishing.
• banner is an OptionLangDict, so it accepts either a plain string (“same banner for every language”) or a per-lang dict.
• The standalone board_group page does not render its own name / desc at the top — only banner, then the section cards. The group’s name is only visible from a parent that references it (or in the navbar / <title> if this is the site root, in which case prefer board_list at /).