R3如何使用脚本标题的Needs字段？(How does R3 use the Needs field of a script header? Is there any impact on namespaces?)

 我想知道R3在处理脚本标题的Needs字段时的行为以及它对字绑定有什么影响。 
 
 背景。 我目前正在尝试将一些R2脚本移植到R3以学习R3。 在R2中，脚本标题的Needs字段本质上只是文档，但我使用自定义函数来引用使脚本运行所需的脚本。 
 
 R3似乎本身调用了Needs引用的脚本，但绑定似乎与执行其他脚本不同。 
 
 例如，当％test-parent.r为： 
 
REBOL [
    title: {test parent}
    needs: [%test-child.r]
]

parent: now
?? parent
?? child
 
 和％test-child是： 
 
REBOL [
    title: {test child}
]

child: now
?? child
 
 R3 Alpha（Saphiron build 22-Feb-2013/11：09：25）返回： 
 
>> do %test-parent.r
Script: "test parent" Version: none Date: none
child: 9-May-2013/22:51:52+10:00
parent: 9-May-2013/22:51:52+10:00
** Script error: child has no value
** Where: get ajoin case ?? catch either either -apply- do
** Near: get :name
 
 我不明白为什么test-parent无法访问％test-child.r设置的Child 
 
 如果我从test-parent.r标头中删除Needs字段，而是在DO％test-child.r中插入一行，则没有错误，脚本按预期执行。 

I'd like to know the behaviour of R3 when processing the Needs field of a script header and what implications for word binding it has.
 
Background. I'm currently trying to port some R2 scripts to R3 in order to learn R3. In R2 the Needs field of a script header was essentially just documentation, though I made use of it with a custom function to reference scripts that are required to make my script run.
 
R3 appears to call the Needs referenced scripts itself, but the binding seems different to DOing the other scripts.
 
For example when %test-parent.r is:
 
REBOL [
    title: {test parent}
    needs: [%test-child.r]
]

parent: now
?? parent
?? child
 
and %test-child is:
 
REBOL [
    title: {test child}
]

child: now
?? child
 
R3 Alpha (Saphiron build 22-Feb-2013/11:09:25) returns:
 
>> do %test-parent.r
Script: "test parent" Version: none Date: none
child: 9-May-2013/22:51:52+10:00
parent: 9-May-2013/22:51:52+10:00
** Script error: child has no value
** Where: get ajoin case ?? catch either either -apply- do
** Near: get :name
 
I don't understand why test-parent cannot access Child set by %test-child.r
 
If I remove the Needs field from test-parent.r header and instead insert a line to just DO %test-child.r then there is no error and the script performs as expected.

原文：https://stackoverflow.com/questions/16462904