Function transformSnippetVariables

src/actions/WrapWithSnippet.ts:128–146

* Replaces the snippet variable with name `placeholderName` with TM_SELECTED_TEXT * * Also replaces any unknown variables with placeholders. We do this so it's * easier to leave one of the placeholders blank. We may make it so that you * can disable this with a setting in the future * @param pa

(
  parsedSnippet: TextmateSnippet,
  placeholderName: string
)

 * @param placeholderName The variable name to replace with TM_SELECTED_TEXT
 */
function transformSnippetVariables(
  parsedSnippet: TextmateSnippet,
  placeholderName: string
) {
  var placeholderIndex = getMaxPlaceholderIndex(parsedSnippet) + 1;

  parsedSnippet.walk((candidate) => {
    if (candidate instanceof Variable) {
      if (candidate.name === placeholderName) {
        candidate.name = "TM_SELECTED_TEXT";
      } else if (!KnownSnippetVariableNames[candidate.name]) {
        const placeholder = new Placeholder(placeholderIndex++);
        candidate.children.forEach((child) => placeholder.appendChild(child));
        candidate.parent.replace(candidate, [placeholder]);
      }
    }
    return true;
  });
}

function getMaxPlaceholderIndex(parsedSnippet: TextmateSnippet) {
  var placeholderIndex = 0;