# File lib/mail/parsers/rfc2822.rb, line 4687 def _nt_id_left start_index = index if node_cache[:id_left].has_key?(index) cached = node_cache[:id_left][index] if cached cached = SyntaxNode.new(input, index...(index + 1)) if cached == true @index = cached.interval.end end return cached end i0 = index r1 = _nt_message_id_text if r1 r0 = r1 else r2 = _nt_no_fold_quote if r2 r0 = r2 else r3 = _nt_obs_id_left if r3 r0 = r3 else @index = i0 r0 = nil end end end node_cache[:id_left][start_index] = r0 r0 end