code: func (r *importReader) readIdent() {
  	c := r.peekByte(true)
  	if !isIdent(c) {
  		r.syntaxError()
  		return
  	}
  	for isIdent(r.peekByte(false)) {
  		r.peek = 0
  	}
  }
docs: // readIdent reads an identifier from the input.
  // If an identifier is not present, readIdent records a syntax error.