{
  "docs": {
    "description": [
      "An implementation of a Universal Turing Machine",
      "See the included Busy Beaver ParamsDiffs for examples on how to program it."
    ]
  },
  "commons": {
    "string_sources": {
      "initial-state": "a",
      "halt-state": "halt",
      "blank-symbol": "0",
      "key": {"Join": {"sources": [{"ScratchpadVar": "state"}, ",", {"ScratchpadVar": "read"}]}}
    },
    "mappers": {
      "r": {"All": [
        {"IfCondition": {
          "condition": {"StringMatches": {
            "source": {"ScratchpadVar": "tape"},
            "matcher": {"LengthIs": 0}
          }},
          "mapper": {"ModifyScratchpadVar": {
            "name": "tape",
            "modification": {"Append": {"Common": "blank-symbol"}}
          }}
        }},
        {"ModifyScratchpadVar": {
          "name": "tape-behind",
          "modification": {"Append": {"Modified": {"source": {"ScratchpadVar": "tape"}, "modification": {"KeepRange": {"start": 0, "end": 1}}}}}
        }},
        {"ModifyScratchpadVar": {
          "name": "tape",
          "modification": {"Remove": 0}
        }}
      ]},
      "l": {"All": [
        {"IfCondition": {
          "condition": {"StringMatches": {
            "source": {"ScratchpadVar": "tape-behind"},
            "matcher": {"LengthIs": 0}
          }},
          "mapper": {"ModifyScratchpadVar": {
            "name": "tape-behind",
            "modification": {"Append": {"Common": "blank-symbol"}}
          }}
        }},
        {"ModifyScratchpadVar": {
          "name": "tape",
          "modification": {"Prepend": {"Modified": {"source": {"ScratchpadVar": "tape-behind"}, "modification": {"KeepRange": {"start": -1}}}}}
        }},
        {"ModifyScratchpadVar": {
          "name": "tape-behind",
          "modification": {"Remove": -1}
        }}
      ]},
      "s": "None"
    }
  },
  "rules": [
    {
      "condition": "Always",
      "mapper": {"All": [
        {"SetScratchpadVar": {
          "name": "state",
          "value": {"Common": "initial-state"}
        }},
        {"SetScratchpadVar": {
          "name": "tape-behind",
          "value": ""
        }},
        {"SetScratchpadVar": {
          "name": "tape",
          "value": {"Part": {"QueryParam": "tape"}}
        }}
      ]}
    },
    {"Repeat": {
      "rules": [
        {
          "condition": {"Not": {"StringIs": {"source": {"ScratchpadVar": "state"}, "value": {"Common": "halt-state"}}}},
          "mapper": {"All": [
            {"IfCondition": {
              "condition": {"StringMatches": {
                "source": {"ScratchpadVar": "tape"},
                "matcher": {"LengthIs": 0}
              }},
              "mapper": {"ModifyScratchpadVar": {
                "name": "tape",
                "modification": {"Append": {"Common": "blank-symbol"}}
              }}
            }},
            {"SetScratchpadVar": {
              "name": "read",
              "value": {
                "Modified": {
                  "source": {"ScratchpadVar": "tape"},
                  "modification": {"KeepRange": {
                    "start": 0,
                    "end": 1
                  }}
                }
              }
            }},
            {"SetScratchpadVar": {
              "name": "tape",
              "value": {"Join": {
                "sources": [
                  {"MapKey": {"map": "state_set", "key": {"Common": "key"}}},
                  {"Modified": {"source": {"ScratchpadVar": "tape"}, "modification": {"KeepRange": {"start": 1}}}}
                ]
              }}
            }},
            {"Common": {"name": {"MapKey": {"map": "state_move", "key": {"Common": "key"}}}}},
            {"SetScratchpadVar": {
              "name": "state",
              "value": {"MapKey": {"map": "state_map", "key": {"Common": "key"}}}
            }}
          ]}
        }
      ],
      "limit": 18446744073709551615
    }},
    {
      "condition": "Always",
      "mapper": {"SetPart": {
        "part": {"QueryParam": "tape"},
        "value": {"Join": {"sources": [{"ScratchpadVar": "tape-behind"}, {"ScratchpadVar": "tape"}]}}
      }}
    }
  ]
}