Trasformare un array in struttura per JSON

[fermat]

ok sistemato:

[
      ......
      ,
    "variations": [
      {
        "regular_price": "15.00",
        "manage_stock": true,
        "stock_quantity": 10,
        "attributes": [
          {
            "name": "Colore",
            "option": "PANNA"
          },
          {
            "name": "Taglia",
            "option": "S"
          }
        ]
      },
      {
        "regular_price": "10.00",
        "manage_stock": true,
        "stock_quantity": 5,
        "attributes": [
          {
            "name": "Colore",
            "option": "PANNA"
          },
          {
            "name": "Taglia",
            "option": "M"
          }
        ]
      },
      {
        "regular_price": "15.00",
        "manage_stock": true,
        "stock_quantity": 7,
        "attributes": [
          {
            "name": "Colore",
            "option": "PANNA"
          },
          {
            "name": "Taglia",
            "option": "L"
          }
        ]
      }
    ]
  }
]