# Thor — Odin Static Site Generator
Thor is a static site generator written in [Odin](https://odin-lang.org), replacing Hugo for the `sbrow.github.io` blog. It lives at `./thor/` as a git subtree with its own `flake.nix`.
## Architecture
```
thor.json ← site config (title, base_url, params, modules, og)
content/ ← markdown and HTML content files
layouts/ ← Mustache templates + partials (user overrides)
assets/ ← CSS (Tufte-based), JS, fonts, images
thor/defaults/ ← bundled default templates (embedded via #directory)
public/ ← build output (generated)
```
### Package structure
```
thor/
├── treesitter/ # FFI types + grammar management (standalone package)
├── markdown/ # Content transformation pipeline (imports ../treesitter)
├── mustache/ # Template engine with lambdas + pipe filters + diagnostics
├── content.odin # Page struct, scan_content, load_page
├── render.odin # Template rendering, data structs, RSS, sitemap
├── site.odin # Config (Flags, Config_File, Site), init_site
├── minify.odin # HTML/CSS minification (imports treesitter)
├── feed.odin # RSS + sitemap generation
├── vfs.odin # Union file system (defaults → modules → site)
├── assets.odin # VFS-based asset copying
├── html.odin # HTML helpers: strip_html_tags, unescape_html, generate_summary
├── opengraph.odin # Open_Graph struct + og_for_site/og_for_page
├── frontmatter.odin # JSON frontmatter parser (supports nested og + lastmod)
├── defaults.odin # DEFAULTS_PATH constant (#directory)
├── main.odin # Entry point
├── bench/ # Template rendering benchmark
└── defaults/layouts/ # Bundled default templates
```
### Source files (main package)
| File | Responsibility |
|---|---|
| `main.odin` | Entry point. Sets `context.logger`, calls `init_site`, `build_vfs`, `site_load_content`, `render_site`. Optional Spall profiling via `SPALL` config flag. |
| `site.odin` | `Flags` (CLI), `Config_File` (thor.json, includes `og: Open_Graph`), `Site` (runtime state + arena + VFS + pages + modules + `og`). `Feature` enum. 5-step `init_site`. Imports `md "markdown"` for `Extension` enum. |
| `content.odin` | `Page` struct (includes `lastmod`, `og`), `scan_content` (section-aware walk that handles leaf bundles), `load_page`, `infer_layout`. Calls `md.process()` for the markdown pipeline. |
| `render.odin` | Template rendering: `render_site`, `render_page_html`, `render_home_html`, `render_section`. Data structs (`Base_Data`, `Page_Data`, `Home_Data`, `Section_Data`). VFS-based template loading with fallback chain (`get_template`). |
| `minify.odin` | HTML/CSS minification via tree-sitter. Imports `ts "treesitter"`. |
| `feed.odin` | RSS feed + sitemap XML. Uses `page.url` for canonical URLs. |
| `vfs.odin` | Union file system: `VFS`, `build_vfs`, `mount_dir`, `mount_subdir`, `mount_recursive`, `vfs_get`, `vfs_get_entry`, `vfs_entry_data`. Layers defaults → modules → site. |
| `assets.odin` | `copy_assets_dir` — iterates VFS entries with `assets/` prefix, minifies CSS, copies verbatim or via `os.copy_file`. |
| `html.odin` | `strip_html_tags` (moved from render.odin), `unescape_html`, `generate_summary` (Hugo-style body summary for OG descriptions). |
| `opengraph.odin` | `Open_Graph` struct (fields ordered per OGP spec, `is_article: Maybe(bool)`). `og_for_site(site)` for site defaults (from config + derived), `og_for_page(site_og, page)` for page-specific (overlay page.og + derive from page data). |
| `frontmatter.odin` | JSON frontmatter parser (`{ }` delimited). Supports `layout`, `lastmod`, and nested `og` object (via `json_get_open_graph`). |
| `defaults.odin` | `DEFAULTS_PATH` constant, resolved at compile time via `#directory` so bundled templates ship in the binary. |
### Subpackages
| Package | Files | Responsibility |
|---|---|---|
| `treesitter/` | `treesitter.odin` | FFI types (`Parser`, `Node`, `Query`, etc.), `@(link_prefix="ts_")` foreign bindings, grammar management (`ensure_parser`, `load_grammar`, `grammar_cache`), statically-linked HTML/CSS grammars |
| `markdown/` | `markdown.odin` | `Extension` enum, `DEFAULT_EXTENSIONS`, `process(body, ext, file_path)` — full pipeline, `parse_extension_list`, `apply_extension_config` |
| | `footnotes.odin` | `strip_definitions` (pre-cmark), `inject_notes` (post-cmark) |
| | `alerts.odin` | `inject_alerts` — GitHub alert blocks (`> [!NOTE]`) → styled blockquotes with semantic class names (`alert-note` etc.) |
| | `emoji.odin` | `expand_emoji` — `:shortcode:` → unicode emoji |
| | `sectionate.odin` | `wrap_sections` — splits HTML at `
` into `` wrappers |
| | `highlight.odin` | Syntax highlighting via tree-sitter. Imports `../treesitter`. |
| `mustache/` | See [Mustache engine](#mustache-engine) below | Template engine |
| `bench/` | `bench.odin` + `templates/` | Standalone template rendering benchmark. Generates 500 posts + 100 comments, renders with indented partials + inheritance + pipes. `--dump ` for output validation, positional arg for iteration count (default 250). |
Icon SVGs live as HTML partials in `layouts/partials/icons/` (home, github, rss, chevron_up, star).
### Data flow
```
thor.json → find_config → init_site (5-step)
→ build_vfs (defaults/layouts → modules → site/layouts, site/assets)
→ site_load_content (scan_content + url computation)
→ render_site
→ load_partials + get_template (VFS + fallback chain)
→ render_page_html / render_home_html / render_section
→ optional minify_html
→ public/
```
## Page struct
```odin
Page :: struct {
section: string, // "" for root, "posts", etc.
slug: string,
layout: string, // inferred or frontmatter override
permalink: string, // relative URL path
url: string, // full canonical URL (base_url + permalink)
title: string,
description: string,
date: string,
lastmod: string,
menu: string,
body_html: string,
draft: bool,
is_starred: bool,
og: Open_Graph, // per-page OG overrides from frontmatter
_is_index: bool `private`,
}
```
No `Page_Type` enum — page type is inferred from section + `_is_index`. Layout is inferred via `infer_layout(section, is_index)`:
- Home (root index): `"home"`
- Section index: `"_index"` (e.g. `"posts_index"`)
- Section page: singularized section (e.g. `"post"`)
- Root page: `"page"`
**Template fallback chain** (in `get_template`): for content pages, `post → page → base`; for section indexes, `posts_index → section_index → page → base`. Fallbacks logged at debug level. Frontmatter `layout` field overrides the inferred value.
## Config system
Config is split into three structs with a clear 5-step initialization flow:
- **`Flags`** — CLI args only. Parsed by `core:flags`. Includes path overrides (`--content`, `--assets`, `--output`, `--layouts`), build-mode toggles (`-drafts`, `-watch`, `-minify`), and `-ext`/`-no-ext` for markdown extension overrides.
- **`Config_File`** — parsed from `thor.json` via `json.unmarshal_string`. Holds title, paths, `markdown_extensions` (JSON), `params` (JSON), `modules` (JSON array of relative paths), `og` (`Open_Graph` struct for site-level OG defaults).
- **`Site`** — runtime state: arena, pages, modules, VFS, `features: bit_set[Feature]`, `markdown_extensions: bit_set[md.Extension]`, `og: Open_Graph` (resolved site-level OG).
**`Feature` enum** — `Drafts`, `Minify`, `Watch`. Checked with `.Minify in site.features`.
**`markdown.Extension` enum** (in the `markdown` package, not main) — `Emoji`, `Sidenotes`, `Alerts`, `Highlight`, `Sections`. Default is `md.DEFAULT_EXTENSIONS` (currently `.Emoji, .Sidenotes, .Alerts`). Configurable via:
- `thor.json`: `"markdown_extensions": { "emoji": true, "highlight": false, ... }`
- CLI: `-ext:highlight,sections` (enable) / `-no-ext:emoji` (disable). Comma-separated, case-insensitive.
**`find_config`** — walks up from CWD looking for `thor.json`. Falls back to `./thor.json`.
Config precedence: `CLI flags > thor.json values > hardcoded defaults`.
```json
{
"title": "...",
"base_url": "...",
"modules": ["../path/to/module"],
"og": {
"image": "https://example.com/og.png"
},
"markdown_extensions": { "emoji": true, "highlight": false },
"params": {
"social": [
{ "name": "github", "url": "...", "icon": "icons/github" }
]
}
}
```
## VFS (Union File System)
Layered directory resolution for templates and assets: `site layouts/ → module layouts/ → defaults/layouts/`.
```odin
VFS :: struct { files: map[string]VFS_Entry }
VFS_Entry :: struct { fs_path: string, data: []byte }
```
`build_vfs` mounts in reverse precedence (defaults first, site last overwrites). `DEFAULTS_PATH` resolved at compile time via `#directory`, so bundled templates ship inside the binary. Modules configured via `"modules": ["../path"]` in `thor.json` — each module contributes `layouts/` and `assets/` subdirectories.
Three access patterns:
- `vfs_get(vfs, path) -> ([]byte, bool)` — data only (lazy-loaded from disk)
- `vfs_get_entry(vfs, path) -> (VFS_Entry, []byte, bool)` — entry + data (for callers that need `fs_path` for diagnostics)
- `vfs_entry_data(entry) -> ([]byte, bool)` — data from an entry already in hand (avoids redundant map lookup when iterating `vfs.files`)
Content is **not yet in the VFS** — `scan_content` still uses direct filesystem reads. (See `TODOS.md`.)
## Open Graph
`Open_Graph` struct in `opengraph.odin` with fields ordered per [ogp.me](https://ogp.me/) spec. `is_article` is `Maybe(bool)` — nil means "unset" (distinguished from explicitly `false`).
**Site-level** (`og_for_site`): starts from `Config_File.og` (user-supplied defaults from `thor.json`), then fills empty fields derivable from `Site`:
- `site_name ← site.title`
- `locale ← "en_US"` (default if unset)
**Page-level** (`og_for_page`): copies site OG, derives page-specific fields, then overlays `Page.og` (from frontmatter):
- `url ← page.url`
- `title ← page.title` (falls back to `site_name` if empty)
- `type ← "article" if !page._is_index else "website"`
- `is_article ← !page._is_index`
- `section ← page.section`
- `published_time / modified_time ← page.date / page.lastmod`
- `description ← page.description`, else body summary (via `generate_summary`)
Paths through maps (e.g. `params.*`) are silently allowed — not validated. Templates access via `{{og.url}}`, `{{og.title}}`, `{{#og.is_article}}`, etc.
## Markdown pipeline
Lives in the `markdown` package. Entry point: `md.process(body, ext, file_path)`. All `.html` content files skip the pipeline entirely — body is used as-is.
```
raw markdown
→ md.strip_definitions (if .Sidenotes — pre-cmark)
→ cmark markdown_to_html (Unsafe mode for HTML passthrough)
→ md.expand_emoji (if .Emoji — post-cmark)
→ md.inject_notes (if .Sidenotes — post-cmark)
→ md.inject_alerts (if .Alerts — post-cmark)
→ md.highlight_code (if .Highlight — post-cmark)
→ md.wrap_sections (if .Sections — post-cmark)
```
Each step is gated by `bit_set[md.Extension]`.
## Template system
Templates use Mustache with template inheritance (`{{
{{> nav}}{{$content}}{{/content}}{{> footer}}
{{
{{page_title}}
{{&body}}
{{/content}}
{{/base}}
```
Data is passed as **typed structs** (not `map[string]any`). Mustache resolves struct fields via Odin reflection, including `using`-embedded fields. Date presence is checked via string truthiness (`{{#date}}`) — no separate `has_date` bool needed. Dates are stored as raw ISO strings; presentation formatting happens in the template via the `format` pipe (see Pipes extension below).
```odin
Base_Data :: struct {
now: string, // UTC ISO 8601 build timestamp
params: json.Value,
body: string,
title: string,
description: string,
og: Open_Graph,
date_format: string, // from site.date.format (thor.json)
timezone: ^datetime.TZ_Region, // loaded from site.date.timezone or local, owned by Site
}
Page_Data :: struct {
using base: Base_Data, // fields promoted via reflection fallback
page_title: string,
date: string, // raw ISO 8601; formatted via `| format` in templates
}
Home_Data :: struct {
using base: Base_Data,
pages: [dynamic]Page_Context,
}
Section_Data :: struct {
using base: Base_Data,
page_title: string,
posts: [dynamic]Page_Context, // flat list; year grouping done in template via pipe
}
```
`render_site` pre-parses all partials and the base layout once (via `mustache.parse`), then per-layout templates are cached in `get_template`. Year-based grouping on section index pages is done in the template via `{{#posts | group_by year}}` (see Pipes extension below) — there is no `Year_Section` Go-side struct.
### Pipes extension
Section tags and interpolation tags may transform the resolved value before rendering:
```handlebars
{{#posts | group_by year}}
{{key}}: {{#items}}{{title}}, {{/items}}
{{/posts}}
```
Currently implemented: `group_by ` (list → list-of-groups) and `format` (ISO date string → display string like "15 Mar 2026"). The `format` pipe resolves `date_format` (string) and `timezone` (`^datetime.TZ_Region`) from the data context. When `timezone` is non-nil, dates are DST-aware converted before formatting. The `MST` token reflects the active timezone abbreviation (e.g. `"EST"`/`"EDT"`) or the source offset (e.g. `"UTC-04:00"`) when no target tz is configured. TZ data is loaded once by `init_site` via `timezone.region_load` using the site arena allocator, stored on `Site.tz`, and freed when the arena is destroyed. Filter results live in `context.temp_allocator` (render-scoped). See `mustache/EXTENSIONS.md` for syntax details, caps (`MAX_PIPES`, `MAX_PIPE_ARGS`), and the `Group` struct shape.
### Comments
`page.html` includes `{{> comments}}`. The `comments.html` partial self-guards with `{{#og.is_article}}` so it only renders on article pages — no separate `is_post` flag.
## Syntax highlighting
Build-time highlighting via Tree-sitter C FFI. No client-side JavaScript.
- **HTML and CSS grammars** statically linked via Nix (`mkGrammarStaticLib` in `thor/flake.nix`). Always available, no `dlopen`.
- **Other grammars** (bash, odin, nu, etc.) loaded via `dlopen` from Helix's compiled `.so` files.
- Highlight queries (`.scm`) loaded from Helix's runtime directory.
- Paths hardcoded in `treesitter/treesitter.odin` (`GRAPHS_PATH`, `QUERIES_PATH`) — Nix store paths, Helix-version-dependent. (See `TODOS.md`.)
- Grammar loading split: `ensure_parser` (parser only, used by minify) vs `load_grammar` (parser + query, used by highlight).
- Capture names mapped to CSS classes: `keyword` → `.hl-keyword`, etc.
- Atom-one-dark color theme in `main.css`.
## Minification
Optional, enabled with `-minify` flag (`.Minify` in `Feature` bit_set).
- **HTML** — tree-sitter parses output, strips comments, removes inter-tag whitespace, preserves `