{
  "@context": "http://www.w3.org/ns/shex.jsonld",
  "type": "Schema",
  "start": "_:S1",
  "shapes": [
    { "type": "ShapeDecl",
    "id": "_:S1",
    "shapeExpr": {
      "type": "Shape",
      "expression": {
        "type": "TripleConstraint",
        "predicate": "http://a.example/p1",
        "min": 0,
        "max": -1,
        "valueExpr": "_:S1"
      }
    } }
  ]
}