{
  "type": "project",
  "input": {
    "type": "leftjoin",
    "input": [
      {
        "type": "bgp",
        "patterns": []
      },
      {
        "type": "bgp",
        "patterns": [
          {
            "type": "pattern",
            "termType": "Quad",
            "subject": {
              "termType": "NamedNode",
              "value": "http://example.org/ns#a"
            },
            "predicate": {
              "termType": "NamedNode",
              "value": "http://example.org/ns#b"
            },
            "object": {
              "termType": "NamedNode",
              "value": "http://example.org/ns#c"
            },
            "graph": {
              "termType": "DefaultGraph",
              "value": ""
            }
          }
        ]
      }
    ]
  },
  "variables": []
}