class ICU::USet

• ICU::USet
• Reference
• Object

Overview

Sets of Unicode Code Points and Strings

ICU::USet is a mutable set of Unicode code points (characters) and multi-character strings. It is used internally by ICU APIs such as ICU::Collator and ICU::Transliterator, and is exposed here as an Enumerable(Char) so that callers can work with ordinary Crystal types.

Sets can be constructed from a character range, from a UnicodeSet pattern string (e.g. "[\\p{L}]", "[a-zA-Z0-9]"), or built up programmatically via #add / #add_range.

For simple inspection you can call #to_set to obtain a plain Set(Char), or iterate directly with #each.

Usage

s = ICU::USet.new('a', 'z') # characters a–z
s.includes?('m')            # => true
s.size                      # => 26
s.to_set                    # => Set{'a', 'b', ..., 'z'}

vowels = ICU::USet.new("[aeiouAEIOU]")
vowels.includes?('e') # => true

See also

• ICU User Guide
• Reference C API
• Unit tests

Included Modules

• Enumerable(Char)

Defined in:

Constructors

• .new(from : Char, to : Char)

  Creates a set containing all characters in the range from..to (inclusive).

• .new(pattern : String)

  Creates a set from a UnicodeSet pattern.

• .new

  Creates an empty set.

Instance Method Summary

• #add(char : Char) : self

  Adds char to this set.

• #add(string : String) : self

  Adds a multi-character string element to this set.

• #add_all(other : USet) : self

  Adds all members of other to this set (union in place).

• #add_range(from : Char, to : Char) : self

  Adds all characters in the range from..to (inclusive) to this set.

• #clear : self

  Removes all members, leaving an empty set.

• #complement : self

  Complements this set: every character previously absent is added, and every character previously present is removed.

• #disjoint?(other : USet) : Bool

  Returns true if this set and other have no characters in common.

• #each(& : Char -> ) : Nil

  Yields each character in this set (string elements are skipped).

• #empty? : Bool

  Returns true if the set contains no characters or strings.

• #finalize
• #includes?(char : Char) : Bool

  Returns true if char is a member of this set.

• #includes?(string : String) : Bool

  Returns true if string (as a multi-character string element) is in this set.

• #includes_all_of?(string : String) : Bool

  Returns true if every character of string is individually in this set.

• #intersects?(other : USet) : Bool

  Returns true if this set and other have at least one character in common.

• #remove(char : Char) : self

  Removes char from this set.

• #remove_all(other : USet) : self

  Removes all members of other from this set (set difference in place).

• #remove_range(from : Char, to : Char) : self

  Removes all characters in the range from..to from this set.

• #retain_all(other : USet) : self

  Retains only the members of other (intersection in place).

• #size : Int32

  Returns the number of characters (and strings) in this set.

• #superset?(other : USet) : Bool

  Returns true if every member of other is also in this set.

• #to_pattern(escape_unprintable : Bool = false) : String

  Returns the UnicodeSet pattern string representing this set.

• #to_set : Set(Char)

  Returns a Crystal Set(Char) with all characters from this set.

• #to_unsafe : LibICU::USet

Constructor Detail

ICU::USet.new('a', 'z').size # => 26

ICU::USet.new("[\\p{Lu}]") # all uppercase letters
ICU::USet.new("[aeiou]")   # vowels

ICU::USet.new

Instance Method Detail

s = ICU::USet.new
s.add('x')
s.includes?('x') # => true

a = ICU::USet.new('a', 'c')
b = ICU::USet.new('d', 'f')
a.add_all(b).size # => 6

s = ICU::USet.new
s.add_range('a', 'f')
s.size # => 6

ICU::USet.new('a', 'c').each { |c| print c } # => abc

ICU::USet.new.empty? # => true

ICU::USet.new('a', 'z').includes?('m') # => true
ICU::USet.new('a', 'z').includes?('M') # => false

ICU::USet.new('a', 'z').includes_all_of?("hello") # => true
ICU::USet.new('a', 'z').includes_all_of?("Hello") # => false

a = ICU::USet.new('a', 'f')
b = ICU::USet.new('d', 'z')
a.retain_all(b).to_set # => Set{'d', 'e', 'f'}

ICU::USet.new('a', 'z').size # => 26

ICU::USet.new('a', 'c').to_pattern # => "[a-c]"

ICU::USet.new('a', 'c').to_set # => Set{'a', 'b', 'c'}