
  xsd2hrc.xsl

  xsd2hrc transformation generates HRC syntax files to parse XML files
from appropriate XML Schema description of these files type.

  Generated HRC syntax supports XML Schema Recomendations,
except some syntax and logic looses. Most of them can't be implemented
due to HRC context-free grammar model limitations.
These includes:

  - Poor namespace checks. It is assumed, that some set of
    frequently used ns prefixes (including empty and any prefixes)
    is provided for each namespace. This set can be easely changed.
  - Elements order check looses.
    Ignoring  difference in  xs:sequence, xs:choose, xs:all,
    treating any of them as <xs:choose minOccurs="0" maxOccurs="unbounded">

  - xs:list/xs:union membertypes order has no importance in xmlschema,
    but can greatly affect syntax results in HRC.

  - Limited xs:import support. Using it implies, that there is
    an already defined HRC type for imported schema, and
    importing schema just refer it with valid hrc type prefix,
    obtained from HRC catalog file using @targetNamespace attribute
    of prototype definition.

  - Ignoring difference in xs:union, xs:list.
  - xs:simpleType/xs:restriction is just reference to base type
    except then using xs:enumeration and xs:pattern facets.
  - Lax buildin simpleTypes support. Treating all of them as lists.
  - Unsupported substitution groups, xsi:type instance element identification.

  - Missed keys and unique constrains checks
  - No xs:redefine support

TODO:
  'fixed' on attr decls
  xs:redefine features
  substitution groups??
