Duplicate characters in Unicode: Difference between revisions

Revision as of 19:41, 16 December 2024

Revision as of 18:41, 19 December 2024

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Unicode has a number of characters specifically designated as [[Roman numerals]], as part of the ''Number Forms'' range from U+2160 to U+2183. For example, Roman 1988 ({{char|MCMLXXXVIII}}) could alternatively be written as {{char|ⅯⅭⅯⅬⅩⅩⅩⅧ}}. This range includes both uppercase and lowercase numerals, as well as pre-combined glyphs for numbers up to 12 ({{char|Ⅻ}} for {{char|XII}}), mainly intended for clock faces.

The pre-combined glyphs should only be used to represent the individual numbers where the use of individual glyphs is not wanted, and not to replace compounded numbers. For example, one can combine {{char|Ⅹ}} with {{char|Ⅰ}} to produce Roman numeral 11 ({{char|ⅩⅠ}}), so U+216A ({{char|Ⅺ}}) is canonically equivalent to {{char|ⅩⅠ}}. Such characters are also referred to as composite compatibility characters or decomposable compatibility characters. Such characters would not normally have been included within the Unicode standard except for compatibility with other existing encodings (see [[Unicode compatibility characters]]). The goal was to accommodate simple translation from existing encodings into Unicode. This makes translations in the opposite direction complicated because multiple Unicode characters may map to a single character in another encoding. Without the compatibility concerns the only characters necessary would be: {{Char|Ⅰ}}, {{Char|Ⅴ}}, {{Char|Ⅹ}}, {{Char|Ⅼ}}, {{Char|Ⅽ}}, {{Char|Ⅾ}}, {{Char|Ⅿ}}, {{Char|ⅰ}}, {{Char|ⅴ}}, {{Char|ⅹ}}, {{Char|ⅼ}}, {{Char|ⅽ}}, {{Char|ⅾ}}, {{Char|ⅿ}}, {{Char|ↀ}}, {{Char|ↁ}}, {{Char|ↂ}}, {{Char|ↇ}}, {{Char|ↈ}}, and {{Char|Ↄ}}, and {{char|ↄ}}; all other Roman numerals can be composed from these characters.

=== Arabic presentation forms ===

{{main|Arabic Presentation Forms-A|Arabic Presentation Forms-B}}{{Expand section|date=December 2024}}

Unicode has encoded compatibility characters for contextual Arabic letter forms where its 4 contextual forms are encoded as separate code points (isolated, final, initial, and medial). For example, {{Codepoint|0647}} has its contextual forms encoded at these 4 code points:

* {{Codepoint|FEE9}}

* {{Codepoint|FEEA}}

* {{Codepoint|FEEB}}

* {{Codepoint|FEEC}}

The contextual-form characters are not recommended for general use. There are also compatibility Arabic ligatures encoded such as {{unichar|FDF2}} and {{unichar|FDFD}}.

There are also compatibility Arabic ligatures encoded such as {{unichar|FDF2}} and {{unichar|FDFD}}.

=== Hebrew presentation forms ===

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The wide variants are listed below:

<!-- Just like the main list; Duplicate character: Original character(s) -->

* {{unichar|FB21}}

* {{unichar|FB22}}

* {{unichar|FB23}}

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* {{unichar|FB28}}

These characters are variants of ordinary Hebrew letters encoded for [[Justification (typesetting)|justification]] of texts written in Hebrew, such as the Torah. Unicode also encodes a stylistic variant of {{Unichar|5e2}} at {{Unichar|FB20}}

== List ==

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*{{Unichar|AA}}: {{Unichar|61}}

*{{Unichar|2139}}: {{Unichar|69}}

*{{Unicharunichar|FB29FB20}}: {{Unicharunichar|002b5e2}}

*{{unichar|FB21}}: {{Unichar|5d0}}

*

* {{unichar|FB22}}: {{Unichar|5d3}}

* {{unichar|FB23}}: {{Unichar|5d4}}

* {{unichar|FB24}}: {{Unichar|5db}}

* {{unichar|FB25}}: {{Unichar|5dc}}

* {{unichar|FB26}}: {{Unichar|5dd}}

* {{unichar|FB27}}: {{Unichar|5e8}}

* {{unichar|FB28}}: {{Unichar|5ea}}

* {{Unichar|FB29}}: {{Unichar|002b}}

==See also==