W3C XML Schema and Compound Types

Consecrating compound types as types Are gMonthDay and gYearMonth really primitive types? Well, someone thought so.
ISO 8601 or else W3C XML Schema is especially adamant about representing dates and times using ISO 8601 notation. If you don't like ISO 8601, too bad. Convert your dates and conform.
"Primitives" per databases Every time I gripe about these (non)primitive types, someone pops up and explains that these things are primitives, per database usage. I'm not sure why that justifies inflicting database usage on markup.
Regular expressions re-appear For validation, W3C XML Schema defines a Unicode-aware subset of regular expressions. Pattern-matching allows testing complex lexical types, but they only use the binary yes/no matching capabilities.