Swift って
a -1 ってエラーになるのか。 $ swift Welcome to Apple Swift version 4.0 (swiftlang-900.0.63.10 clang-900.0.36). Type :help for assistance. 1> let a = 42 a: Int = 42 2> a -1 error: repl.swift:2:2: error: consecutive statements on a line must be separated by ';' a -1 ^ ;