blocks|key|783753|text|::运算符引用全局作用域，而不是局部作用域。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|783754|entityMap^0|0|2|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

A <code>::</code> operator refers to the global scope instead of local.

blocks|key|998164|text|module+A
++def+self.method;+"Outer";+end
end
module+B
++module+A
++++def+self.method;+"Inner";+end
++end
++A.method+++#+=>+"Inner"
++::A.method+#+=>+"Outer"
end|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|998165|在特殊情况下，在您所显示的文件的line+41中定义了一个内部Net模块。为了保持对外部Net模块的访问，它使用::Net。|unstyled|offset|length|style|CODE|998166|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/wycats/artifice/blob/master/lib/artifice.rb#L41^0|0|V|3|18|3|1K|5|G|7|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|T|8|@$G|U|H|V|I|J]|$G|W|H|X|I|J]|$G|Y|H|Z|I|J]]|9|@$G|10|H|11|1|12]]|A|$]]|$1|K|3|-4|5|F|7|13|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

<pre><code>module A
 def self.method; "Outer"; end
end
module B
 module A
 def self.method; "Inner"; end
 end
 A.method # =&gt; "Inner"
 ::A.method # =&gt; "Outer"
end
</code></pre>

On the specific case of Artifice, at <a href="https://github.com/wycats/artifice/blob/master/lib/artifice.rb#L41">line 41</a> of the file that you've shown is defined a inner <code>Net</code> module. To keep acess to the outer <code>Net</code> module, it uses <code>::Net</code>.

blocks|key|998232|text|::是作用域解析操作符。它所做的是确定一个模块可以在什么范围内找到。例如：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|998233|module+Music
++module+Record
++++#+perhaps+a+copy+of+Abbey+Road+by+The+Beatles?
++end

++module+EightTrack
++++#+like+Gloria+Gaynor,+they+will+survive!
++end
end

module+Record
++#+for+adding+an+item+to+the+database
end|code-block|syntax|javascript|998234|要从Music外部访问Music::Record，您需要使用Music::Record。|998235|要从Music::EightTrack引用Music::Record，可以简单地使用Record，因为它是在相同的作用域(Music的作用域)中定义的。|998236|然而，要从Music::EightTrack访问负责与数据库交互的Record模块，您不能只使用Record，因为Ruby认为您需要Music::Record。这时您可以使用作用域解析操作符作为前缀，指定全局/主作用域：::Record。|998237|entityMap^0|0|2|0|0|2|5|B|D|U|D|0|2|H|L|D|16|6|1P|5|0|5|H|X|6|1C|6|1U|D|32|8|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|13|8|@$9|14|A|15|B|C]|$9|16|A|17|B|C]|$9|18|A|19|B|C]|$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1C|8|@$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]|$9|1J|A|1K|B|C]|$9|1L|A|1M|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|1N|8|@]|D|@]|E|$]]]|R|$]]

The <code>::</code> is the scope resolution operator. What it does is determines what scope a module can be found under. For example:

<pre><code>module Music
 module Record
 # perhaps a copy of Abbey Road by The Beatles?
 end

 module EightTrack
 # like Gloria Gaynor, they will survive!
 end
end

module Record
 # for adding an item to the database
end
</code></pre>

To access <code>Music::Record</code> from outside of <code>Music</code> you would use <code>Music::Record</code>.

To reference <code>Music::Record</code> from <code>Music::EightTrack</code> you could simply use <code>Record</code> because it's defined in the same scope (that of <code>Music</code>).

However, to access the <code>Record</code> module responsible for interfacing with your database from <code>Music::EightTrack</code> you can't just use <code>Record</code> because Ruby thinks you want <code>Music::Record</code>. That's when you would use the scope resolution operator as a prefix, specifying the global/main scope: <code>::Record</code>.

I was reading through the source of <a href="https://github.com/wycats/artifice" rel="noreferrer">Artifice</a> and saw:

<pre><code>module Artifice
 NET_HTTP = ::Net::HTTP
 # ...
end
</code></pre>

line: <a href="https://github.com/wycats/artifice/blob/master/lib/artifice.rb#L6" rel="noreferrer">https://github.com/wycats/artifice/blob/master/lib/artifice.rb#L6</a>

Why not just do <code>Net::HTTP</code> instead of <code>::Net::HTTP</code>, i.e., what does it mean when you use <code>::</code> as a prefix?

Ruby: what does :: prefix do?

数据库

我通读了一下的源代码，发现：module Artifice  NET_HTTP = ::Net::HTTP  # ...end线路：为什么不直接使用Net::HTTP而不是::Net::HTTP，也就是说，当你使用::作为前缀时，这意味着什么？

问Ruby: prefix是做什么的？
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