_nt_grammar_name (Treetop::Compiler::Metagrammar)

    # File lib/treetop/compiler/metagrammar.rb, line 494
          def _nt_grammar_name
            start_index = index
            if node_cache[:grammar_name].has_key?(index)
              cached = node_cache[:grammar_name][index]
              @index = cached.interval.end if cached
              return cached
            end

            i0, s0 = index, []
            if input.index(Regexp.new('[A-Z]'), index) == index
              r1 = instantiate_node(SyntaxNode,input, index...(index + 1))
              @index += 1
            else
              r1 = nil
            end
            s0 << r1
            if r1
              s2, i2 = [], index
              loop do
                r3 = _nt_alphanumeric_char
                if r3
                  s2 << r3
                else
                  break
                end
              end
              r2 = instantiate_node(SyntaxNode,input, i2...index, s2)
              s0 << r2
            end
            if s0.last
              r0 = instantiate_node(SyntaxNode,input, i0...index, s0)
              r0.extend(GrammarName0)
            else
              self.index = i0
              r0 = nil
            end

            node_cache[:grammar_name][start_index] = r0

            return r0
          end