* 仕様書

[REFS[
- [1] [[Unicode Standard]] ([TIME[2016-07-19 02:38:02 +09:00]]) <http://www.unicode.org/versions/latest/ch03.pdf#page=44>
- [6] [CITE@en-us[UAX #44: Unicode Character Database]], [TIME[2020-03-06T22:23:11.000Z]], [TIME[2020-10-21T08:36:06.386Z]] <https://www.unicode.org/reports/tr44/#Character_Decomposition_Mappings>
- [7] [CITE@en-us[UAX #44: Unicode Character Database]], [TIME[2020-03-06T22:23:11.000Z]], [TIME[2020-10-21T08:49:23.551Z]] <https://www.unicode.org/reports/tr44/#Property_Invariants>
]REFS]

* 意味

[2] [DFN[[RUBYB[分解写像]@en[decomposition mapping]]]]は、
1つの[[文字]]から[[正準等価]]または[[互換等価]]であるか、
または[[ハングル字母]]に関する規定に基づく1つ[[以上]]の[[文字]]の[[列]]への[[写像]]です [SRC[>>1]]。

[3] [DFN[[RUBYB[分解可能文字]@en[decomposable character]]]]
([DFN[[RUBYB[事前合成済み文字]@en[precomposed character]]]]、
[DFN[[RUBYB[合成文字]@en[composite character]]]]) は、
[[分解写像]]によって1つ[[以上]]の他の[[文字]]の[[列]]と[[等価]]となる[[文字]]です [SRC[>>1]]。

[4] [DFN[[RUBYB[分解]@en[decomposition]]]]は、
1つ[[以上]]の[[文字]]の[[列]]で、[[分解可能文字]]と[[等価]]なものです [SRC[>>1]]。

[5] [[文字列]]の[DFN[[RUBYB[完全分解]@en[full decomposition]]]]は、
それ以上どの[[文字]]も[[分解]]できなくなるまで[[列]]中の各[[文字]]を[[分解]]したものです
[SRC[>>1]]。

* [CODE[Decomposition_Type]]

- [9] [CITE@en-us[UAX #44: Unicode Character Database]], [TIME[2020-03-06T22:23:11.000Z]], [TIME[2020-10-21T06:24:49.510Z]] <https://www.unicode.org/reports/tr44/#Default_Values_Table>
- [10] [CITE@en-us[UAX #44: Unicode Character Database]]
([TIME[2015-06-12 05:19:39 +09:00]] 版)
<http://www.unicode.org/reports/tr44/#Decomposition_Type>
- [11] [CITE@en-us[UAX #44: Unicode Character Database]], [TIME[2020-03-06T22:23:11.000Z]], [TIME[2020-10-21T08:24:32.981Z]] <https://www.unicode.org/reports/tr44/#Derived_Extracted>

[FIG(quote)[
[FIGCAPTION[
[8] [CITE[perlunicode - search.cpan.org]]
([TIME[2016-04-23 14:38:03 +09:00]] 版)
<http://search.cpan.org/dist/perl/pod/perlunicode.pod#Unicode_Character_Properties>
]FIGCAPTION]

> \p{Decomposition_Type: Non_Canonical} (Short: \p{Dt=NonCanon})
> Matches a character that has a non-canonical decomposition.

]FIG]



* メモ