# File lib/treetop/compiler/metagrammar.rb, line 1652
      def _nt_sequence_primary
        start_index = index
        if node_cache[:sequence_primary].has_key?(index)
          cached = node_cache[:sequence_primary][index]
          if cached
            cached = SyntaxNode.new(input, index...(index + 1)) if cached == true
            @index = cached.interval.end
          end
          return cached
        end

        i0 = index
        i1, s1 = index, []
        r2 = _nt_prefix
        s1 << r2
        if r2
          r3 = _nt_atomic
          s1 << r3
        end
        if s1.last
          r1 = instantiate_node(SyntaxNode,input, i1...index, s1)
          r1.extend(SequencePrimary0)
          r1.extend(SequencePrimary1)
        else
          @index = i1
          r1 = nil
        end
        if r1
          r0 = r1
        else
          i4, s4 = index, []
          r5 = _nt_prefix
          s4 << r5
          if r5
            r7 = _nt_space
            if r7
              r6 = r7
            else
              r6 = instantiate_node(SyntaxNode,input, index...index)
            end
            s4 << r6
            if r6
              r8 = _nt_predicate_block
              s4 << r8
            end
          end
          if s4.last
            r4 = instantiate_node(SyntaxNode,input, i4...index, s4)
            r4.extend(SequencePrimary2)
            r4.extend(SequencePrimary3)
          else
            @index = i4
            r4 = nil
          end
          if r4
            r0 = r4
          else
            i9, s9 = index, []
            r10 = _nt_atomic
            s9 << r10
            if r10
              r11 = _nt_suffix
              s9 << r11
            end
            if s9.last
              r9 = instantiate_node(SyntaxNode,input, i9...index, s9)
              r9.extend(SequencePrimary4)
              r9.extend(SequencePrimary5)
            else
              @index = i9
              r9 = nil
            end
            if r9
              r0 = r9
            else
              r12 = _nt_atomic
              if r12
                r0 = r12
              else
                @index = i0
                r0 = nil
              end
            end
          end
        end

        node_cache[:sequence_primary][start_index] = r0

        r0
      end