def _nt_feature_elements
start_index = index
if node_cache[:feature_elements].has_key?(index)
cached = node_cache[:feature_elements][index]
@index = cached.interval.end if cached
return cached
end
s0, i0 = [], index
loop do
i1 = index
r2 = _nt_scenario
if r2
r1 = r2
else
r3 = _nt_scenario_outline
if r3
r1 = r3
else
@index = i1
r1 = nil
end
end
if r1
s0 << r1
else
break
end
end
r0 = instantiate_node(SyntaxNode,input, i0...index, s0)
r0.extend(FeatureElements0)
node_cache[:feature_elements][start_index] = r0
r0
end