def _nt_month
start_index = index
if node_cache[:month].has_key?(index)
cached = node_cache[:month][index]
@index = cached.interval.end if cached
return cached
end
i0 = index
i1, s1 = index, []
r2 = _nt_FWS
s1 << r2
if r2
r3 = _nt_month_name
s1 << r3
if r3
r4 = _nt_FWS
s1 << r4
end
end
if s1.last
r1 = instantiate_node(SyntaxNode,input, i1...index, s1)
r1.extend(Month0)
else
@index = i1
r1 = nil
end
if r1
r0 = r1
else
r5 = _nt_obs_month
if r5
r0 = r5
else
@index = i0
r0 = nil
end
end
node_cache[:month][start_index] = r0
r0
end