> ## Documentation Index
> Fetch the complete documentation index at: https://rive.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# TextFileFormat

A FileFormat for text. Files with a claimed extension import as in-band
text documents, editable in the editor and synced across collaborators,
and the callbacks below drive the text editor's intelligence. Documents
export as plain blobs, so scripts read them via `context:blob(name)` at
both edit time and runtime.

Analysis callbacks are pure functions of `(doc, parsed)`; state lives
only in views. `parsed` carries the cached result of `parse`, or nil when
`parse` is not implemented.

```lua theme={null}
local format: TextFileFormat = {
    name = 'Markdown',
    extensions = { 'md' },
}

return function(): TextFileFormat
    return format
end
```

## Fields

### `name`

Display name of the format, e.g. "Markdown".

### `extensions`

File extensions handled, without dots, e.g. `{"md", "markdown"}`.

## Methods

### `parse`

<div class="signature">
  ```lua theme={null}
  parse(doc: FormatDocument) -> buffer?
  ```
</div>

Optional. Called once per document version; the returned buffer is
cached by Rive, keyed to the document's content, and passed back into
every other callback. Within one VM the same buffer object is reused;
across VMs the bytes are copied once.

### `view`

<div class="signature">
  ```lua theme={null}
  view(doc: FormatDocument, editor: EditorContext, surface: FormatSurface, parsed: buffer?) -> FormatView?
  ```
</div>

Creates the preview for a document on a surface. Each surface gets
its own view; a document can be visible on several at once.

### `highlight`

<div class="signature">
  ```lua theme={null}
  highlight(doc: FormatDocument, parsed: buffer?) -> {FormatToken}
  ```
</div>

Returns highlight tokens for the document.

### `diagnostics`

<div class="signature">
  ```lua theme={null}
  diagnostics(doc: FormatDocument, parsed: buffer?) -> {FormatDiagnostic}
  ```
</div>

Returns problems for the document.

### `completions`

<div class="signature">
  ```lua theme={null}
  completions(doc: FormatDocument, line: number, column: number, parsed: buffer?) -> {FormatCompletion}
  ```
</div>

Returns completions at the given position.

### `hover`

<div class="signature">
  ```lua theme={null}
  hover(doc: FormatDocument, line: number, column: number, parsed: buffer?) -> FormatHover?
  ```
</div>

Returns hover documentation at the given position, or nil.

### `format`

<div class="signature">
  ```lua theme={null}
  format(doc: FormatDocument, parsed: buffer?) -> string?
  ```
</div>

Returns the fully formatted text, or nil to leave the document
unchanged. Rive diffs the result against the current text and applies
minimal edits.