L2/09-051

Subject: Regex in UAX 29
From:    Mark Davis
Date:    Tue, 27 Jan 2009

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We've tested and verified that the following regex pattern matches
the grapheme cluster definition in UAX 29 Unicode Text Segmentation.
It would be useful to add it to UAX 29.

( ( CR LF )
  | ( Prepend*
      ( L+ | (L* ( ( V | LV ) V* | LVT ) T*) | T+ | [^ Control CR LF ] )
      ( Extend | SpacingMark )* )
  | . )

Moreover, where there are straightforward regex patterns corresponding
to other segmentation boundaries, they should be added as well. At this
point, we anticipate that to be word boundaries (but not linebreak or
sentence break).

Mark