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These symbols are:
- individual special characters
- quoted-strings
- domain-literals
- comments
- atoms
The first four of these symbols are self-delimiting. Atoms
are not; they are delimited by the self-delimiting symbols and
by linear-white-space. For the purposes of regenerating
sequences of atoms and quoted-strings, exactly one SPACE is
assumed to exist, and should be used, between them. (Also, in
the "Clarifications" section on "White Space", below, note the
rules about treatment of multiple contiguous LWSP-chars.)
So, for example, the folded body of an address field
":sysmail"@ Some-Group. Some-Org,
Muhammed.(I am the greatest) Ali @(the)Vegas.WBA
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下面这些符号组合(是结构化的消息):
- 特殊字符
- 被引串(被引号引起来的字符串)
- 域名
- 注释
- 词
前四种是"本身可以确定分割界限的"(self-delimiting)，词不可以；
他们被自己的分割符号和分行符所分割。为了分割开一组原子词和被引号引起来的字符串，
我们假设它们之间存在一个空格( 可以在下面的"White Space"的"Clarifications"节中
找到这点，注意这个规则和如何处理多个相邻的空格有关)
如上所说，例如，一个地址域的消息体的折叠内容如下：
":sysmail"@ Some-Group. Some-Org,
Muhammed.(I am the greatest) Ali @(the)Vegas.WBA
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is analyzed into the following lexical symbols and types:
:sysmail quoted string
@ special
Some-Group atom
. special
Some-Org atom
, special
Muhammed atom
. special
(I am the greatest) comment
Ali atom
@ atom
(the) comment
Vegas atom
. special
WBA atom
The canonical representations for the data in these addresses
are the following strings:
":sysmail"@Some-Group.Some-Org
and
Note: For purposes of display, and when passing such struc-
tured information to other systems, such as mail proto-
col services, there must be NO linear-white-space
between <word>s that are separated by period (".") or
at-sign ("@") and exactly one SPACE between all other
<word>s. Also, headers should be in a folded form.
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上面的例子串分析完成以后，变成了下面序列的词和类型
:sysmail 被引串
@ 特殊字符
Some-Group 词
. 特殊字符
Some-Org 词
, 特殊字符
Muhammed 词
. 特殊字符
(I am the greatest) 注释
Ali 词
@ 词
(the) 注释
Vegas 词
. 特殊字符
WBA 词
规范的表述这个地址的方法如下：
":sysmail"@Some-Group.Some-Org
和
注意：为了消息终端显示,或者把这些结构化的信息传递到别的系统, 例如
邮件服务器. 这些被点(".")或者圈号("@")分割的词之间一定不能存在分行符
(不能在地址中间折行),每个地址之间应该存在一个空格. 另外,地址的消息头
应该采用折叠的格式(大概是说应该一个地址折一行)
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