addHandler( "literal-restriction",
new LiteralRestrictionHandler() );
addHandler( "variable-restriction",
new VariableRestrictionsHandler() );
addHandler( "predicate",
new PredicateHandler() );
addHandler( "return-value-restriction",
new ReturnValueRestrictionHandler() );
addHandler( "qualified-identifier-restriction",
new QualifiedIdentifierRestrictionHandler() );