references

Winnow makes extensive use of JSONPath style references within its documents. A reference looks like $ref:/materials/opendesk/sheets/wood/composite/plywood/birch-faced-plywood

References can be used to create composite documents that re-use other documents. For example here the values of a set::string option are strings that reference other documents.

    "options": {
        "material": {
            "type": "set::string", 
            "values": "$ref:/materials/opendesk/sheets/wood/composite/plywood/birch-faced-plywood"
        }, 
        "processes": {
            "options": {
                "oiling": "$ref:/processes/opendesk/oiling", 
                "sanding": "$ref:/processes/opendesk/fine-sanding"
            }, 
            "type": "set::string", 
            "value": "finishing-processes"
        }
    },

You can also reference portions of other documents using JSONPath’s xpath style annotation. Here the options for material-choices are copied in from the context /contexts/opendesk/standard-materials :

    "options": {
        "material-choices": "$ref:/contexts/opendesk/standard-materials~/options/material-choices"
    },

It’s also possible to include a subset of another document by using an options key along with a reference. Here a specific thickness of plywood is targeted in the document /sizes/opendesk/1220-x-2440-mm

"size": {
    "type": "set::resource", 
    "values": [
        {
            "$ref": "/sizes/opendesk/1220-x-2440-mm", 
            "options": {
                "thickness": {
                    "type": "numeric::number", 
                    "value": 18.0
                }
            }
        }
    ]
}