Question

我尝试用红色执行此脚本https://www.mail-archive.com/rebol-bounce@rebol.com/msg01222.html但我无法理解为什么

calc-workdays now / date 3-feb-2007 [1-feb-2007]

***脚本错误：＆gt;运算符缺少参数

***其中：做

*** Stack：打印calc-workdays

    found?: func [
        "Returns TRUE if value is not NONE."
        value
    ][
        not none? :value
    ]

    calc-workdays: func [
        "Return number of workdays between two dates, excluding holidays"
        date1 [date!] "Start date"
        date2 [date!] "End date"
        holidays [block!] "Block of dates to exclude (holidays, etc.)"
        /non "Return number of non-work days (weekend + holidays) between 2 dates"
        /local days day1 day2 diff param
    ][
        days: copy []
        set [day1 day2] sort reduce [date1 date2]
        diff: day2 - day1
        param: pick [[> 5 union][< 6 exclude]] either found? non [1][2]
        loop diff [
            day1: day1 + 1
            if do param/1 day1/weekday param/2 [append days day1]
        ]
        return length? do param/3 days holidays
    ]

Answer 1

Rebol2似乎允许你通过WORD！做，并评估它。如果这个单词恰好是一个包含ANY-FUNCTION！的变量，它将被运行......如果它是一个中缀＆＃34; OP！＆＃34;那么它就会像 not infix一样运行。

>> do quote > 1 2
== false

>> do quote < 1 2
== true

红色也是如此，但DO不是变量。它只能运行0个arity函数：

>> foo: does [print "hi"]

>> do quote foo
hi    

>> bar: func [x] [print x]

>> do quote bar "hi"
*** Script Error: bar is missing its x argument

有问题的脚本试图使用此功能。但它可以用普通的COMPOSE或REDUCE来完成。所以改变：

if do param/1 day1/weekday param/2 [append days day1]

要：

if do reduce [day1/weekday param/1 param/2] [append days day1]

这将构建一个代码块，其中>或<运算符位于中间，并且正常执行它而不依赖于此WORD！-dispatch或DO的中继丢弃行为。< / p>

同样，改变：

return length? do param/3 days holidays

要：

return length? do reduce [param/3 days holidays]

通过这些更改，并删除found?（没有必要），它似乎可以正常工作。

Rebol calc-workdays不适用于Red

1 个答案: