A <data type=> pattern now carries a SimpleType (base + facets) rather
than a bare built-in, and its <param name=>value</param> children
populate the facets (minLength, maxLength, length, pattern, min/max
inclusive/exclusive, total/fraction digits), reusing the XSD datatype
facet validation. So a constrained datatype like xsd:string with
minLength rejects too-short values.
datatypeLibrary resolution, typed <value> comparison, and the RNC
datatype parameter blocks remain.
Part of #79
Add the RELAX NG pattern algebra (Pattern, NameClass), a parser for the XML
syntax into a grammar of start plus named defines, and James Clark's
derivative validation algorithm. The pattern is derived through each
start-tag, attribute, text, and end-tag event with simplifying constructors;
the document is valid when the residual pattern is nullable. Supports
element, attribute, text, empty, notAllowed, group, choice, interleave,
optional, zeroOrMore, oneOrMore, mixed, list, ref/define, data, value, and
the name classes; handles interleave and recursive grammars, reusing the XSD
datatype library for data and value.
Closes#11Closes#12
