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Surrogate Pairs

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Surrogate pairs are character representations in source code that represent a single character that consists of a sequence of two Unicode values. In a coded pair, the first value is a high surrogate and the second is a low surrogate. A high surrogate is a character in the range U+D800 through U+DBFF. A low surrogate is a character in the range U+DC00 through U+DFFF. Surrogate pairs extend the character set beyond the Unicode character. When you create a word breaker, it is recommended that, when the word breaker handles surrogate pairs, the word breaker consider the following rules:

  • A high surrogate must precede a low surrogate.
  • A low surrogate must follow a high surrogate.
  • A high or low surrogate without a corresponding value has no meaning.

Word breakers must consider any pairs and generate the pairs as such in the index.

For more information, see Surrogates and Supplementary Characters.