invalid regex Block Escapes not reported for ICU

[Paul J. Lucas]

When using ICU, a query such as:

  fn:matches( "a", "\p{IsBasic-Latin}" )

returns "true" even though it should raise error err:FORX0002 since IsBasic-Latin is not a valid Block Escape according to:

  http://www.w3.org/TR/xmlschema-2/#charcter-classes

in [36]. (It should be IsBasicLatin -- no '-'.)

[Paul J. Lucas (paul-lucas)]

The XML Schema Part 2 specification includes the note:

Note: [Unicode Database] is subject to future revision. For example, the mapping from code points to character properties might be updated. All ·minimally conforming· processors ·must· support the character properties defined in the version of [Unicode Database] that is current at the time this specification became a W3C Recommendation. However, implementors are encouraged to support the character properties defined in any future version.

Since the Unicode Database can grow over time, there's no easy way to know what is and isn't legal.