{
    "expr": "Phone ~> $filter(function($p) {$p.type = 'home'}) ~> $single(function($p) {$p.number = '0203 544 1234'})",
    "dataset": "dataset1",
    "bindings": {},
    "result": {
        "type": "home",
        "number": "0203 544 1234"
    }
}