fn

params => positional-params* 或者 positional-params* & next-param

positional-param => binding-form

next-param => binding-form

name => symbol

定义一个（匿名）函数。

user=> (fn greeting [name]                                          ; 创建匿名函数
           (str "Hello, " name " ."))
;#<user$eval1$greeting__2 user$eval1$greeting__2@616fde>

user=> ((fn greeting [name]                                         ; 应用匿名函数
           (str "hello, " name " ."))
        "moto")
"hello, moto ."

user=> ((fn greeting                                                ; 参数重载（arity overloading）
            ([name]
                (greeting "Hello" name))
            ([msg name]
                (str msg ", " name " .")))
        "moto")
"Hello, moto ."

user=> ((fn greeting                                                ; 接受不定数量参数的函数
            [name & others]
            (if (seq others)
                (str "Hello, " name " and others: " others " .")
                (str "Hello, " name " .")))
        "moto" "nokia" "apple")
"Hello, moto and others: (\"nokia\" \"apple\") ."

讨论

comments powered by Disqus