Smalltalk中的消息转发 [英] Message forwarding in Smalltalk

问题描述

因此，我正在编写一个应用程序，其中一个对象具有一堆将消息转发到的委托对象.我的想法是我可以说

So I'm writing an application where one object has a bunch of delegate objects that it forwards messages to. The idea is that I can say

someObject sendMessage:aMessage

和aMessage将被发送到someObject的所有委托(对于aMessage的任何值).我能够做到这一点的唯一方法是:

and aMessage will be sent to all of someObject's delegates (for any value of aMessage). The only way I've been able to do this is something like:

sendMessage:aMessage

| sel chunks kwords arglist msg |
chunks := aMessage findTokens:' '.
kwords := Array new:(chunks size).
arglist := Array new:(chunks size).
1 to: (chunks size) do: [:i | 
    kwords at:i put:((chunks at:i) findTokens:':') at:1.
    arglist at:i put:((chunks at:i) findTokens:':') at:2].
sel := ''.
kwords do:[:word | sel := sel,word,':'].

msg := Message selector:sel arguments:arglist.
delegates do:[:del | del perform:msg selector with:msg arguments].

它可以工作，但是必须有更好的方法.该解决方案将参数限制为字符串，这很丑陋.有谁知道一种更干净，更好的邮件转发方式?

It works, but there has to be a better way. This solution limits the arguments to being strings, and is just plain ugly. Does anyone know a cleaner, better way to forward messages?

顺便说一句，我正在使用吱吱声，但最好采用与实现无关的解决方案;)

BTW, I'm using squeak, but an implementation-independent solution would be prefered ;)

编辑:我应该补充一下，这些委托与该对象属于同一类，所以我不能仅仅覆盖DidsNotUnderstand:.

EDIT: I should add that the delegates are of the same class as the object, so I can't just override DoesNotUnderstand:.

推荐答案

由于要将对象作为参数传递，因此必须将它们作为使用如下消息模式的单独列表传递:

Since you want to pass objects in as arguments, you'll have to pass them in as a separate list of using a message pattern like the following:

someObject sendMessage:带参数的aSelector:argumentsList

someObject sendMessage: aSelector withArguments: argumentList

然后您将#sendMessage:withArguments:实现为:

Then you'd implement #sendMessage:withArguments: as:

sendMessage:带有参数的aSelector:argumentList

sendMessage: aSelector withArguments: argumentList

代表行事:[:del | 删除执行:aSelector withArguments::argumentList].

delegates do:[:del | del perform: aSelector withArguments: :argumentList].

，您将能够使用真实对象作为args转发任意复杂的消息:

and you'd be able to forward arbitrarily complex messages using real objects as args:

|参数|

| arguments |

参数:=数组 使用:新对象 与:1234.5 带有:(键"->值").

arguments := Array with: Object new with: 1234.5 with: ('key'->'value').

someObject sendMessage:#foo:bar:baz:withArguments:arguments

someObject sendMessage: #foo:bar:baz: withArguments: arguments

我认为这对于大多数方言也是可移植的...

I think this is portable to most dialects as well...

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