用法

FORSKIP 'word skip-num body

描述

在系列中评估块以获取周期性值。

FORSKIP 是一个函数值。

参数

word -- 设置为系列中每个位置的单词，并作为结果而更改（类型：单词）
skip-num -- 每次跳过的值的数量（类型：整数）
body -- 每次评估的块（类型：块）

(特殊属性)

抛出
捕捉

源代码

forskip: func [
    "Evaluates a block for periodic values in a series." 
    [throw catch] 
    'word [word!] {Word set to each position in series and changed as a result} 
    skip-num [integer!] "Number of values to skip each time" 
    body [block!] "Block to evaluate each time" 
    /local orig result
][
    if not positive? skip-num [throw make error! join [script invalid-arg] skip-num] 
    if not any [
        series? get word 
        port? get word
    ] [throw make error! {forskip/forall expected word argument to refer to a series or port!}] 
    orig: get word 
    while [any [not tail? get word (set word orig false)]] [
        set/any 'result do body 
        set word skip get word skip-num 
        get/any 'result
    ]
]