如何在一次调用中扩展具有多个功能的对象？答案

【问题标题】：How to extend object with multiple functions in one call?如何在一次调用中扩展具有多个功能的对象？
【发布时间】：2014-08-14 17:23:42
【问题描述】：

在 Rebol 3 中，您可以通过 append 向对象动态添加键和值：

>> foo: object [x: 10]

>> append foo [y: 20 z: 30]
== make object! [
    x: 10
    y: 20
    z: 30
]

但是如果你用函数来尝试，它似乎不起作用：

>> foo: object [x: 10]

>> append foo reduce [y: does [print "y"] z: does [print "z"]]
** Script error: invalid argument: make function! [[][print "y"]]
** Where: append
** Near: append foo reduce [y: does [print "y"] z: does [print "z"]]

你可以用extend添加一个函数：

>> foo: object [x: 10]

>> extend foo 'y does [print "y"]

>> foo/y
y

但这只能让您一次添加一个。如何将任意键/值块添加到对象中，并使用其中的一些函数？

【问题讨论】：

标签： object rebol rebol3

【解决方案1】：

由于extend只是一个夹层，

>> source extend
extend: make function! [[
   {Extend an object, map, or block type with word and value pair.}
   obj [object! map! block! paren!] "object to extend (modified)"
   word [any-word!]
   val
][
  if :val [append obj reduce [to-set-word word :val]]
  :val
]]

您可以轻松定义自己的扩展或新功能

extends: make function! [  [{Extend an object}
   obj  [object!]
   funcblk [block!]  "with pair(s) of functionname and function"
] [
   foreach [name funcon] funcblk [append obj reduce [to-set-word name get funcon]]
]]

然后你就可以了

>> r: does [print "y"] s: does [print "z"]
>> extends foo [y r z s]
== make object! [
   x: 10
   y: make function! [[][print "y"]]
   z: make function! [[][print "z"]]
]

或简称

>> append foo reduce [quote y: does [print "y"] quote z: does [print "z"]]
== make object! [
    x: 10
    y: make function! [[][print "y"]]
    z: make function! [[][print "z"]]
]

【讨论】：

啊，很明显！它试图完成任务。 :-/ 我应该多加注意。谢谢。