August 2018
Beginner to intermediate
382 pages
7h 14m
Chinese
Content preview from Perl语言入门
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Unicode
入门
｜
351
这和
é
的组合形式、分解形式相类似。
é
的两种表示方法实际上可说是完全等价
（
canonically equivalent
）的，因为不管如何构造这个字素，最终的视觉呈现和
字素意义都是相同的。但
fi
和
fi
的视觉呈现并不相同，所以它们只是不完全等价
（
compatibility equivalent
）的。不管是完全等价还是不完全等价，我们都不需要关
心如何分解为方便排序的普通形式（见图
C-2
）。参见
Unicode Standard Annex
第
15
条，“
Unicode Normalization Forms
”，进一步了解其中细节。
图C-
2
：我们可以分解并重新组合完全等价的字素表示形式，但只能分解不完全等价的字素表
示形式
比如你想要检查字符串中是否包含
é
或者
fi
，但并不关心原始用的是哪种字符表示
形式。首先，需要将字符串分解为普通形式，这好比是在做归一化。要分解
Unicode
字符串，得用
Perl
自带的
Unicode::Normalize
模块，它提供了两个分解字符串的函
数。你可以用
NFD
（
Normalization Form Decomposition
）子程序把完全等价形式的字
素转换为对应的分解形式。另外，也可以用
NFKD
（
Normalization Form Kompatibility
Decomposition
）子程序分解不完全等价的字素。下面例子中的字符串包含了组合字
符，之后再以不同方式分解后匹配。包含“
oops ...
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