[]=

# File actionpack/lib/action_dispatch/journey/gtg/transition_table.rb, line 163
        def []=(from, to, sym)
          to_mappings = states_hash_for(sym)[from] ||= {}
          case sym
          when Regexp
            # we must match the whole string to a token boundary
            if sym == DEFAULT_EXP
              sym = DEFAULT_EXP_ANCHORED
            else
              sym = /\A#{sym}\Z/
            end
          when Symbol
            # account for symbols in the constraints the same as strings
            sym = sym.to_s
          end
          to_mappings[sym] = to
        end