def _nt_alphanumeric_char
start_index = index
if node_cache[:alphanumeric_char].has_key?(index)
cached = node_cache[:alphanumeric_char][index]
@index = cached.interval.end if cached
return cached
end
i0 = index
r1 = _nt_alpha_char
if r1
r0 = r1
else
if has_terminal?('\G[0-9]', true, index)
next_character = index + input[index..-1].match(/\A(.)/um).end(1)
r2 = true
@index = next_character
else
r2 = nil
end
if r2
r0 = r2
else
@index = i0
r0 = nil
end
end
node_cache[:alphanumeric_char][start_index] = r0
r0
end