24 • Rust uses macros for situations where you want to have a variable number of arguments (no function overloading). • 所謂「衛生」巨集，是指這類巨集不會誤從自身所用於的範圍內擷取 ID。Rust 巨集實際上只能算是 部分衛生的巨集。 • Rust 是多範式的語言。舉例來 println!("gcd: {}", gcd(143, 52)); } • 宣告參數後面接有型別 (與某些程式設計語言相反)，然後才是傳回型別。 • The last expression in a function body (or any block) becomes the return value. Simply omit the ; at the end of the expression. The is idiomatic at the end of a function (refactor gcd to use a return). • 某些函式沒有回傳值，會傳回 () 這個「單位型別」。如果省略-> () 傳回型別，編譯器則會推斷出 這點。 • Overloading is not supported – each function has a single implementation

. . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Mathematical Operations and Elementary Functions 30 6.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Annotated Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 9 Functions 72 9.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 9.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9.5 Operators With Special Names

. . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Mathematical Operations and Elementary Functions 30 6.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Annotated Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 9 Functions 72 9.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 9.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9.5 Operators With Special Names

. . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Mathematical Operations and Elementary Functions 30 6.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Annotated Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 9 Functions 72 9.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 9.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9.5 Operators With Special Names

. . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Mathematical Operations and Elementary Functions 30 6.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Annotated Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 9 Functions 72 9.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 9.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9.5 Operators With Special Names

. . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Mathematical Operations and Elementary Functions 30 6.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Annotated Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 9 Functions 72 9.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 9.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9.5 Operators With Special Names

. . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Mathematical Operations and Elementary Functions 30 6.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Annotated Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 9 Functions 72 9.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 9.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9.5 Operators With Special Names

. . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Mathematical Operations and Elementary Functions 30 6.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Annotated Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 9 Functions 72 9.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 9.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9.5 Operators With Special Names

. . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Mathematical Operations and Elementary Functions 30 6.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Annotated Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 9 Functions 72 9.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 9.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 9.5 Operators With Special Names

. . . . . . . . . . . . . . . . . . . . . . . . . 25 5 Mathematical Operations and Elementary Functions 26 5.1 Arithmetic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Raw String Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 8 Functions 67 8.1 Argument Passing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 8.4 Operators Are Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 8.5 Operators With Special Names