Spellcheck typst files with LanguageTool.

1. compile the document
2. extract text content
3. check text with languagetool
4. map results back to the source

• different LanguageTool backends can be used to check the text
• atleast one backend must be enabled for cargo install ... with --features=<backend>
• one backend must be selected for typst-languagetool ... with the required flags

• typst-languagetool starts a LanguageTool instance with JNI
• requires maven and the executable is not portable
• add feature bundle
• specify flag --bundle for cli or "backend: "bundle" for LSP

• typst-languagetool starts a LanguageTool instance with JNI
• requires JAR with languagetool
• add feature jar
• specify flag jar_location=<path> for cli or "backend: "jar" and "jar_location": <path> for LSP

• typst-languagetool connects to a running LanguageTool server
• add feature server
• specify flags host=<host> and port=<port> for cli or "backend: "server", "host: <host> and "port": <port> for LSP

• terminal
  • install command line interface (CLI)
    • cargo install --git=https://github.com/antonWetzel/typst-languagetool cli --features=...
  • Check on time or watch for changes
    • typst-languagetool check ...
    • typst-languagetool watch ...
  • Path to check
    • typst-languagetool watch --path=<directory or file>
    • typst-languagetool check --path=<file>
  • Main file of the document
    • defaults to path if not specified
    • check the complete document if a path is not specified
    • --main=<file>
  • Project root can be changed
    • defaults to main parent folder
    • --root=<path>
• vs-codium/vs-code
  • install language server protocal (LSP)
    • cargo install --git=https://github.com/antonWetzel/typst-languagetool lsp --features=...
  • install generic lsp (editors/vscodium/generic-lsp/generic-lsp-0.0.1.vsix)
  • configure options (see below)
  • hints should appear
    • first check takes longer
• neovim
  • install language server protocal (LSP)
    • cargo install --git=https://github.com/antonWetzel/typst-languagetool lsp --features=...
  • copy the editors/nvim/typst.lua file in the ftplugin/ folder (should be in the nvim config path)
  • configure options in init_option (see below)
  • create a main.typst file and include your typst files inside if needed
  • hints should appear (if not use set filetype=typst to force the type)
    • first check takes longer

/// Additional allowed words for language codes
dictionary: HashMap<String, Vec<String>>,
/// Languagetool rules to ignore (WHITESPACE_RULE, ...) for language codes
disabled_checks: HashMap<String, Vec<String>>,
/// preferred language codes
languages: HashMap<String, String>,
/// Functions calls to ignore (lorem, bibliography, cite, ...)
ignore_functions: HashSet<String>,

/// use bundled languagetool
backend: "bundle" | "jar" | "server",
/// path for jar backend
jar_location: Option<String>,
/// host for server backend
host: Option<String>,
/// port for server backend
port: Option<String>,

/// Size for a text chunk to send to LanguageTool
chunk_size: usize,


/// Project Root
root: Option<PathBuf>,
/// Project Main File
main: Option<PathBuf>,

/// Path to check a different file as the main file
path: Option<PathBuf>,
/// Delay to wait after a file change
delay: f64,
/// Output the diagnostic plain without color
plain: bool,
/// Path to a JSON file to load common options
options: Option<PathBuf>,

/// Duration to wait for additional changes before checking the file
/// Leave empty to only check on open and save
on_change: Option<std::time::Duration>,
/// Path to a JSON file to load common options
options: Option<PathBuf>,

// use styling for spellcheck only in the spellchecker
// keep the correct styling in pdf or preview
// should be called after the template
#show: lt()

// use styling for spellcheck in pdf or preview
// should be called after the template
#show: lt(overwrite: true) 

// Setup special styling to improve the conversion to plain text before checking with LanguageTool.
#let lt(overwrite: false, seperate-sections-level: 3) = {
  // only apply the styling if overwrite is true or the spellcheck input exists
  if not sys.inputs.at("spellcheck", default: overwrite) {
    return doc => doc
  }
  return doc => {
    // replace math with
    // inline: 0 (smaller size to avoid line height changes)
    // block: nothing
    show math.equation.where(block: false): it => text("0", size: 0.8em)
    show math.equation.where(block: true): it => []

    // autogenerated and a lot of names, just remove it
    show bibliography: it => []

    // setup consisting line spacing
    set par(justify: false, leading: 0.65em, hanging-indent: 0pt)

    // avoid page breaks
    set page(height: auto)
    show block: it => it.body

    // remove page numbering
    show page: set page(numbering: none)

    // split pages before important headings
    show heading: it => if it.level <= seperate-sections-level {
      pagebreak() + it
    } else {
      it
    }

    doc
  }
}

The compiled document contains the text language, but not the region.

#set text(
    lang: "de", // included
    region: "DE", // lost
)

The text language is used to determine the region code ("de-DE", ...). If another region is desired, it can be specified in the languages parameter.

"languages": {
	"en": "en-US",
	"de": "de-DE",
}