and collation according to the Unicode Common Locale Data Repository rules. More...

and collation according to the Unicode Common Locale Data Repository rules.

The CLDR specifies five levels of comparison.

• The primary or base level considers all variant codepoints representing a character to be equivalent regardless of case or decorations like accents and vowel or tone marks.
• The secondary level differentiates between letters with decorations but still ignores case.
• The tertiary level differentiates based on case, decorations, and variants, for example A and Ⓐ.
• The Quaternary level differentiates words with punctuation, for example "ab" and "a-b".
• Identical differentiates all codepoints with no implicit normalization so a character constructed with combining marks will compare different from the same character represented as a single codepoint.