#
# RELAX NG Schema for SPARQL Query Results XML Format
#
# This XML schema is normative.
# $Id$
#
#

namespace local = ""
namespace res = "http://www.w3.org/2005/sparql-results#"
namespace xsi = "http://www.w3.org/2001/XMLSchema-instance"
datatypes xsd = "http://www.w3.org/2001/XMLSchema-datatypes"


start = sparql

xmlLang = attribute xml:lang { text }

# Using xsi namespaced terms such as xsi:schemaLocation
# is tricky. as Relax requires them to be given when used.  However,
# WXS has this knowledge built in and validators complain when they
# are explicitly listed without a schemaLocation (which is forbidden by
# the WXS spec)..

xsiSchemaLoc = attribute xsi:schemaLocation { string }


sparql = element res:sparql { 
    xsiSchemaLoc?, head,
    (results | boolean)
}

head = element res:head {
    varName*, link*
}

varName = element res:variable {
    nameAttr
}

nameAttr = attribute name {
    xsd:NMTOKEN
}

hrefAttr = attribute local:href {
    URI-reference
}

link = element res:link {
    hrefAttr
}

ordered = attribute local:ordered {
    xsd:boolean
}

distinct = attribute local:distinct {
    xsd:boolean
}

results = element res:results { 
    ordered, distinct, result*
}


# ASK
boolean = element res:boolean {
    xsd:boolean
}

# SELECT solution, single match or row
result = element res:result {
    indexAttr?, binding*
}

# SELECT binding in a solution
binding = element res:binding {
    nameAttr,
    ( uri | bnode | literal | unbound )
}

uri = element res:uri { 
    text
}

bnode = element res:bnode {
    text
}

literal = element res:literal { 
    datatypeAttr?, xmlLang?,
    text
}

unbound = element res:unbound {
    empty
}

indexAttr = attribute local:index {
    xsd:positiveInteger
}

datatypeAttr = attribute local:datatype {
    URI-reference
}

URI-reference = xsd:anyURI