message: Command names must only contain letters
diff: @@ -9,7 +9,13 @@ import * as utils from '../utils/utils'
  * @param position The position to be scanned at.
  */
  function commandTokenizer(document: vscode.TextDocument, position: vscode.Position): string | undefined {
  - const startResult = document.getText(new vscode.Range(new vscode.Position(position.line, 0), position)).match(/\\(?=[^\\{},[\]]*$)/)
  + let startRegex: RegExp
  + if (document.languageId === 'latex-expl3') {
  + startRegex = /\\(?=[^\\{},[\]]*$)/
  + } else {
  + startRegex = /\\(?=[a-zA-Z]*$)/
  + }
  + const startResult = document.getText(new vscode.Range(new vscode.Position(position.line, 0), position)).match(startRegex)
  if (startResult === null || startResult.index === undefined || startResult.index < 0) {
  return undefined
  }
  