In fact if you want to specify some kind of rigid schema (and for SOAP/XML Schema it usually is needlessly rigid) you are reinventing either ASN.1 or SunRPC's X

In fact if you want to specify some kind of rigid schema (and for SOAP/XML Schema it usually is needlessly rigid) you are reinventing either ASN.1 or SunRPC's XDR, only with larger overhead...