code: public void visitBracketedExpression(Expr expr, Integer indent) {
  		boolean needsBrackets = needsBrackets(expr);
  		if (needsBrackets) {
  			out.print("(");
  		}
  		visitExpression(expr, indent);
  		if (needsBrackets) {
  			out.print(")");
  		}
  	}
docs: Write a bracketed operand if necessary. Any operand whose human-readable
  representation can contain whitespace must have brackets around it.
  
  @param operand
  @param enclosing
  @param out