Regular expressions are used throughout much of the world's software for matching and manipulating text. UTS #18: Unicode Regular Expressions provides the foundation for the handling of Unicode text in those expressions.

Version 17 of this standard adds the Bidi_Paired_Bracket and Bidi_Paired_Bracket_Type properties, both new in Unicode 6.3, and it expands the guidelines and requirements for support of the Script_Extensions property.