{ index in let indent = String(repeating: " ", count: index) let stringIndex = str.index(str.startIndex, offsetBy: index) print("∖(indent) ∖(str[stringIndex])") } } func fuga(_ text: String) { if !text.isEmpty { let count = text.count (0..<count).forEach { i in let indent = String(repeating: " ", count: i) let index = text.index(text.startIndex, offsetBy: i) print(" ∖(indent) ∖(text[index])") } } } これらがどのような 構文木になっているか調べる