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rebol 函数中是否可以有静态变量？

发布于 2024-09-01 16:22:15 字数 314 浏览 1 评论 0原文

这展示了如何在对象或上下文中拥有静态变量： http://www.mail-archive.com/[email protected]/msg04764.html

但是范围对于某些需求来说太大了，是否可以在对象函数内部有一个静态变量？

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猫九 2024-09-08 16:22:15

或者您可以使用FUNCTION/WITH。这使得函数生成器采用第三个参数，该参数定义了一个用作“self”的持久对象：

accumulate: function/with [value /reset] [
    accumulator: either reset [
        value
    ] [
        accumulator + value
    ]
] [
    accumulator: 0
]

要使用它：

>> accumulate 10
== 10

>> accumulate 20
== 30

>> accumulate/reset 0
== 0

>> accumulate 3
== 3

>> accumulate 4
== 7

您可能还需要查看我的 FUNCS 函数。

Or you can use FUNCTION/WITH. This makes the function generator take a third parameter, which defines a persistent object that is used as the "self":

accumulate: function/with [value /reset] [
    accumulator: either reset [
        value
    ] [
        accumulator + value
    ]
] [
    accumulator: 0
]

To use it:

>> accumulate 10
== 10

>> accumulate 20
== 30

>> accumulate/reset 0
== 0

>> accumulate 3
== 3

>> accumulate 4
== 7

You may also want to look at my FUNCS function.

回复收藏 0 原文

来世叙缘 2024-09-08 16:22:15

在 Rebol 3 中，使用闭包（或 CLOS）而不是函数（或 FUNC）。

在 Rebol 2 中，通过包含静态值的块来伪造它，例如：

f: func [
   /local sb
][
     ;; define and initialise the static block
 sb: [] if 0 = length? sb [append sb 0]

     ;; demonstate its value persists across calls
 sb/1: sb/1 + 1
 print sb
 ]

    ;; sample code to demonstrate function
 loop 5 [f]
 == 1
 == 2
 == 3
 == 4
 == 5

In Rebol 3, use a closure (or CLOS) rather than a function (or FUNC).

In Rebol 2, fake it by having a block that contains your static values, eg :

f: func [
   /local sb
][
     ;; define and initialise the static block
 sb: [] if 0 = length? sb [append sb 0]

     ;; demonstate its value persists across calls
 sb/1: sb/1 + 1
 print sb
 ]

    ;; sample code to demonstrate function
 loop 5 [f]
 == 1
 == 2
 == 3
 == 4
 == 5

回复收藏 0 原文

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