# OrgSwift

A dependency-free Swift library that renders a practical subset of
[org-mode](https://orgmode.org) to sanitized HTML. Pure Foundation — no
SwiftUI, WebKit, UIKit, or third-party packages.

Originally extracted from the hand-rolled renderer in the Hutch iOS client so it
could be shared across apps, and since rebuilt around an element tree: org is
parsed once into a document model, and each output format walks it. See
[ARCHITECTURE.md](ARCHITECTURE.md).

## Supported syntax

Headings (with trailing `:tags:`), paragraphs, ordered/unordered lists (with
arbitrary-depth nesting, wrapped lines, and `[ ]`/`[x]`/`[-]` task checkboxes),
description lists (`term :: definition` → `<dl>`), multi-paragraph list items,
tables (with `:---:` alignment), `#+begin_src` / `example` / `quote` / `center` /
`verse` / `export` blocks and `#+begin_<name>` special blocks,
`#+TITLE`/`#+AUTHOR`/`#+DATE` metadata, `#+CAPTION`/`#+ATTR_HTML`/`#+NAME`
figures, org links and images (`[[file:x.png]]` → `<img>`, `[[dest][label]]` →
link, `[[id:target]]` → `#target`), horizontal rules, comments, timestamps
(`<2024-01-15 Mon>`, inactive, times, and ranges → `<time>`), footnotes
(references, inline, and definitions → a `<section class="footnotes">`), and
inline markup (`*bold*`, `/italic/`, `~code~`, `=verbatim=`, `+strike+`,
`_underline_`, `x^2` superscript, bare-URL and email autolinks). Other
`#+KEYWORD:` lines are consumed as document metadata.

Output is sanitized: only `http`/`https`/`mailto` link schemes and
`http`/`https` image schemes are allowed; everything else is dropped.

## Usage

```swift
import OrgSwift

let html = OrgRenderer.renderToHTML(orgSource)
```

### Relative links

Pass an `OrgRenderOptions` to rewrite repository-relative links and images to
absolute `blob` URLs. When `owner`/`repositoryName` are nil (the default),
relative links are left as-is, which the scheme allowlist then drops.

```swift
let html = OrgRenderer.renderToHTML(
    orgSource,
    options: OrgRenderOptions(
        host: "git.sr.ht",       // default
        owner: "~ccleberg",
        repositoryName: "Hutch",
        ref: "HEAD",             // default
        readmePath: "README.org" // resolves paths relative to this file
    )
)
```

`./images/badge.svg` then resolves to
`https://git.sr.ht/~ccleberg/Hutch/blob/HEAD/images/badge.svg`.

### Title and heading level

Two presentation knobs, both defaulting to how Hutch rendered:

- `metadataHeader` (default `true`) — emit a leading `<div class="org-metadata">`
  with the `#+TITLE`/`#+AUTHOR`/`#+DATE`. Set `false` to drop it (e.g. when the
  surrounding UI shows the title itself).
- `headingLevelOffset` (default `0`) — added to each heading's star count, clamped
  to `1...6`. Default renders `*` as `<h1>`; use `1` to render `*` as `<h2>`,
  leaving `<h1>` for a document title.

### Syntax highlighting

Code blocks are highlighted through a protocol so the library carries no
highlighter dependency:

```swift
public protocol CodeHighlighter {
    func highlightedHTML(code: String, language: String?) -> String?
}
```

The default `PlainCodeHighlighter` returns `nil`, so blocks fall back to escaped
`<pre><code>`. Provide your own conformer to plug in a real highlighter:

```swift
let html = OrgRenderer.renderToHTML(orgSource, highlighter: MyHighlighter())
```

A conformer returning `nil` for a given block gets the same escaped fallback.

## Conformance

OrgSwift is tested against the shared [org-conformance](../org-conformance)
corpus, whose golden outputs come from `orgo` (itself validated against Emacs
`ox-html`). `swift test` locates a sibling `../org-conformance` checkout, or set
`ORG_CONFORMANCE_DIR`. The suite reduces both this renderer's HTML and orgo's to
a semantic skeleton and compares them; the current pass/divergence state is
recorded per case, so a closed gap or a regression both surface as a failing
test. See [GAPS.md](GAPS.md) for the outstanding backlog.