{
  "type": "project",
  "input": {
    "type": "join",
    "input": [
      {
        "type": "graph",
        "input": {
          "type": "filter",
          "input": {
            "type": "bgp",
            "patterns": [
              {
                "type": "pattern",
                "termType": "Quad",
                "subject": {
                  "termType": "Variable",
                  "value": "s"
                },
                "predicate": {
                  "termType": "Variable",
                  "value": "p"
                },
                "object": {
                  "termType": "Variable",
                  "value": "o"
                },
                "graph": {
                  "termType": "DefaultGraph",
                  "value": ""
                }
              }
            ]
          },
          "expression": {
            "type": "expression",
            "subType": "operator",
            "operator": "uri",
            "args": [
              {
                "type": "expression",
                "subType": "term",
                "term": {
                  "termType": "Variable",
                  "value": "s"
                }
              }
            ]
          }
        },
        "name": {
          "termType": "NamedNode",
          "value": "http://graph.example.com/"
        }
      },
      {
        "type": "graph",
        "input": {
          "type": "bgp",
          "patterns": [
            {
              "type": "pattern",
              "termType": "Quad",
              "subject": {
                "termType": "Variable",
                "value": "s"
              },
              "predicate": {
                "termType": "Variable",
                "value": "p"
              },
              "object": {
                "termType": "Variable",
                "value": "o"
              },
              "graph": {
                "termType": "DefaultGraph",
                "value": ""
              }
            }
          ]
        },
        "name": {
          "termType": "NamedNode",
          "value": "http://other.example.com/"
        }
      }
    ]
  },
  "variables": [
    {
      "termType": "Variable",
      "value": "s"
    }
  ]
}