Unicode

Functions for Unicode strings.

List of functions

• Unicode::IsUtf(String) -> Bool

  Checks whether a string is a valid utf-8 sequence. For example, the string "\xF0" isn't a valid utf-8 sequence, while the string "\xF0\x9F\x90\xB1" correctly describes a utf-8 cat emoji.

• Unicode::GetLength(Utf8{Flags:AutoMap}) -> Uint64

  Returns the utf-8 string's length in characters (unicode code points). Surrogate pairs are counted as one character.

SELECT Unicode::GetLength("august"); -- 6

• Unicode::Find(string:Utf8{Flags:AutoMap}, subString:Utf8, [pos:Uint64?]) -> Uint64?

• Unicode::RFind(string:Utf8{Flags:AutoMap}, subString:Utf8, [pos:Uint64?]) -> Uint64?

  Searches for the first (RFind — last) substring occurrence in the string starting from the pos position. Returns the first character position from the found string. Null is returned in case of failure.

SELECT Unicode::Find("aaa", "bb"); -- Null

• Unicode::Substring(string:Utf8{Flags:AutoMap}, from:Uint64?, len:Uint64?) -> Utf8

  Returns a substring from the string, starting from the from character, with length equaling len characters. If the len argument is omitted, the substring is taken to the end of the source string.
  If from is greater than the source string length, an empty "" string is returned.

select Unicode::Substring("0123456789abcdefghij", 10); -- "abcdefghij"

• Unicode::Normalize... functions reduce the transmitted utf-8 string to a normal form:

  • Unicode::Normalize(Utf8{Flags:AutoMap}) -> Utf8 -- NFC
  • Unicode::NormalizeNFD(Utf8{Flags:AutoMap}) -> Utf8
  • Unicode::NormalizeNFC(Utf8{Flags:AutoMap}) -> Utf8
  • Unicode::NormalizeNFKD(Utf8{Flags:AutoMap}) -> Utf8
  • Unicode::NormalizeNFKC(Utf8{Flags:AutoMap}) -> Utf8

• Unicode::Translit(string:Utf8{Flags:AutoMap}, [lang:String?]) -> Utf8

  Transliterates with Latin letters the words from the passed string, consisting entirely of characters of the alphabet of the language passed by the second argument. If no language is specified, the words are transliterated from Russian. Available languages: "kaz", "rus", "tur", and "ukr".

select Unicode::Translit("Тот уголок земли, где я провел"); -- "Tot ugolok zemli, gde ya provel"

• Unicode::LevensteinDistance(stringA:Utf8{Flags:AutoMap}, stringB:Utf8{Flags:AutoMap}) -> Uint64

  Calculates the Levenshtein distance for the passed strings.

• Unicode::Fold(Utf8{Flags:AutoMap}, [ Language:String?, DoLowerCase:Bool?, DoRenyxa:Bool?, DoSimpleCyr:Bool?, FillOffset:Bool? ]) -> Utf8

  Performs case folding for the transmitted string.
  Parameters:

  • Language is set following the same rules as in Unicode::Translit()
  • DoLowerCase makes the string lower case. By default, it's true
  • DoRenyxa turns characters with diacritics into similar Latin characters. By default, it's true
  • DoSimpleCyr turns Cyrillic characters with diacritics into similar Latin characters. By default, it's true
  • FillOffset is not used

select Unicode::Fold("Kongreßstraße",  false AS DoSimpleCyr, false AS DoRenyxa); -- "kongressstrasse"
select Unicode::Fold("ҫурт"); -- "сурт"
SELECT Unicode::Fold("Eylül", "Turkish" AS Language); -- "eylul"

• Unicode::ReplaceAll(input:Utf8{Flags:AutoMap}, find:Utf8, replacement:Utf8) -> Utf8

• Unicode::ReplaceFirst(input:Utf8{Flags:AutoMap}, find:Utf8, replacement:Utf8) -> Utf8

• Unicode::ReplaceLast(input:Utf8{Flags:AutoMap}, find:Utf8, replacement:Utf8) -> Utf8

  Replaces all/first/last occurrence(s) of the find string in input through replacement.

• Unicode::RemoveAll(input:Utf8{Flags:AutoMap}, symbols:Utf8) -> Utf8

• Unicode::RemoveFirst(input:Utf8{Flags:AutoMap}, symbols:Utf8) -> Utf8

• Unicode::RemoveLast(input:Utf8{Flags:AutoMap}, symbols:Utf8) -> Utf8

  Removes all/first/last occurrence(s) of characters defined in a symbols set from input. The second argument is interpreted as an unordered set of characters to be deleted.

select Unicode::ReplaceLast("absence", "enc", ""); -- "abse"
select Unicode::RemoveAll("abandon", "an"); -- "bdo"

• Unicode::ToCodePointList(Utf8{Flags:AutoMap}) -> List<Uint32>

  Splits the string into a unicode sequence of codepoints.

• Unicode::FromCodePointList(List<Uint32>{Flags:AutoMap}) -> Utf8

  Forms a unicode string from codepoints.

select Unicode::ToCodePointList("Rumex"); -- [1065, 1072, 1074, 1077, 1083, 1100]
select Unicode::FromCodePointList(AsList(99,111,100,101,32,112,111,105,110,116,115,32,99,111,110,118,101,114,116,101,114)); -- "code points converter"  

• Unicode::Reverse(Utf8{Flags:AutoMap}) -> Utf8

  Reverses the string.

• Unicode::ToLower(Utf8{Flags:AutoMap}) -> Utf8

• Unicode::ToUpper(Utf8{Flags:AutoMap}) -> Utf8

• Unicode::ToTitle(Utf8{Flags:AutoMap}) -> Utf8

  Changes the character case in the string to upper, lower, or title case.

• Unicode::SplitToList( string:Utf8?, separator:Utf8, [ DelimeterString:Bool?, SkipEmpty:Bool?, Limit:Uint64? ]) -> List<Utf8>

  Splits the string into substrings with a separator.
  string -- source string
  separator -- separator
  Parameters:

  • DelimeterString:Bool? — treating a delimiter as a string (true, by default) or a set of characters "any of" (false)
  • SkipEmpty:Bool? - whether to skip empty strings in the result, is false by default
  • Limit:Uint64? - Limits the number of fetched components (unlimited by default); if the limit is exceeded, the raw suffix of the source string is returned in the last item

• Unicode::JoinFromList(List<Utf8>{Flags:AutoMap}, separator:Utf8) -> Utf8

  Concatenates a list of separator-delimited strings into a single string.

select Unicode::SplitToList("One, two, three, four, five", ", ", 2 AS Limit); -- ["One", "two", "three, four, five"]
select Unicode::JoinFromList(["One", "two", "three", "four", "five"], ";"); -- "One;two;three;four;five"

• Unicode::ToUint64(string:Utf8{Flags:AutoMap}, [prefix:Uint16?]) -> Uint64

  Converts from the string into a number.
  The second optional argument defines the numerical system. By default, it is 0 — automatic definition based on prefix.
  Supported prefixes: 0x(0X) — base-16, 0 — base-8. By default, the system is base-10.
  '-' in front of a number is interpreted as in the C language's unsigned arithmetic, e.g. -0x1 -> UI64_MAX.
  If a string contains invalid characters, or a number is beyond ui64, the function finishes with an error.

• Unicode::TryToUint64(string:Utf8{Flags:AutoMap}, [prefix:Uint16?]) -> Uint64?

  Acts similarly to Unicode::ToUint64(), but returns Null instead of an error.

select Unicode::ToUint64("77741"); -- 77741
select Unicode::ToUint64("-77741"); -- 18446744073709473875
select Unicode::TryToUint64("asdh831"); -- Null

• Unicode::Strip(string:Utf8{Flags:AutoMap}) -> Utf8

  Cuts off the string's outermost characters of Space Unicode category.

select Unicode::Strip("\u200ыкль\u2002"u); -- "ыкль"

• Unicode::IsAscii(string:Utf8{Flags:AutoMap}) -> Bool

  Checks whether the utf-8 string consists exclusively of ASCII characters.

• Unicode::IsSpace(string:Utf8{Flags:AutoMap}) -> Bool

• Unicode::IsUpper(string:Utf8{Flags:AutoMap}) -> Bool

• Unicode::IsLower(string:Utf8{Flags:AutoMap}) -> Bool

• Unicode::IsAlpha(string:Utf8{Flags:AutoMap}) -> Bool

• Unicode::IsAlnum(string:Utf8{Flags:AutoMap}) -> Bool

• Unicode::IsHex(string:Utf8{Flags:AutoMap}) -> Bool

  Checks whether the utf-8 string satisfies the specified condition.

• Unicode::IsUnicodeSet(string:Utf8{Flags:AutoMap}, unicode_set:Utf8) -> Bool

  Checks whether the utf-8 string consists exclusively of characters indicated in unicode_set. Characters in unicode_set must be indicated in square brackets.

select Unicode::IsUnicodeSet("ваоао"u, "[вао]"u); -- true
select Unicode::IsUnicodeSet("ваоао"u, "[ваб]"u); -- false

The Unicode library is based on Arcadia's util/charset/ and library/cpp/unicode/.