# `ShotUn.Trace.Mermaid`
[🔗](https://github.com/jcschuster/ShotUn/blob/v0.2.1/lib/shot_un/trace/mermaid.ex#L1)

Renders a `ShotUn.Trace` as a Mermaid `graph TD` diagram.

Terms, substitutions and pair sides are rendered as LaTeX via
`ShotDs.Util.LatexFormatter` and embedded inside a single `$$…$$`
math block per label. Multi-line labels use `\begin{aligned}…`
`\end{aligned}` with an empty `&` at the head of each row for left
alignment; prose (headers, "(empty σ)", …) lives inside `\text{…}`.
All LaTeX fragments are maximally grouped in `{…}` so stray `_`, `^`
or `\lambda` produced by the formatter bind only to the token they
belong to.

Two renderer quirks are worked around at the label-generation layer,
because Mermaid's Kino/Livebook pipeline hits them both:

  * **`\\` row separators are halved.** Mermaid's quoted-label parser
    treats `\\` as an escape and emits a single `\`. That would
    collapse the KaTeX row break to a literal control-space. We emit
    `\\\\` (four backslashes) so Mermaid halves it back to the `\\`
    KaTeX expects.

  * **`~` and `\ ` produce ` ` in the KaTeX HTML.** That
    entity is undefined in SVG's XML DTD and breaks "Save as SVG"
    downloads with `error … Entity 'nbsp' not defined`. Both are
    rewritten to `\,` (thin space, rendered via CSS margin, no HTML
    entity in the DOM).

`<br/>` HTML line breaks are **not** used — Mermaid drops them once
the label parser hits `$$…$$`, collapsing everything onto one line.
Everything lives inside the single math environment instead.

Edge styling mirrors `ShotTx.Proof.to_mermaid/2`: branching choice
points (multiple children) use solid arrows (`==>`); linear
continuations use dotted arrows (`-.->`). Node colours encode the
node kind — start (blue), step (gray), solution (green), fail
(orange).

## Options

  * `:show_state` — include the work-list (and accumulated σ for
    solution leaves) in each node's label. Defaults to `true`.

# `render`

```elixir
@spec render(
  ShotUn.Trace.t(),
  keyword()
) :: String.t()
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*