<s:report test="@from and @target">Only one of the attributes @target and @from may be supplied on <s:name/> </s:report>
Schematron
<s:report test="@to and @target">Only one of the attributes @target and @to may be supplied on <s:name/> </s:report>
Schematron
<s:report test="@to and not(@from)">If @to is supplied on <s:name/>, @from must be supplied as well</s:report>
Schematron
<s:report test="contains(normalize-space(@to),' ') or contains(normalize-space(@from),'
')">The attributes @to and @from on <s:name/> may each contain only a single value</s:report>