code: function parseIdentPattern (inp) {
      var match = inp.takeAPeek(IDENT);
      if (match) {
        if (inp.takeAPeek("@")) {
          var patt = parseBinderPattern(inp);
          if (patt) return nodeBinder(match[0], patt);
        }
        return nodeIdentifier(match[0])
      }
    }
docs: Parses identifiers and binders, which are for when you want to destructure the value but also pass the original value to the function. Binders are an identifier, followed by an @ and another pattern.