gistfile1.txt

// this bit is pseudo code to describe the filter expression


type ComparisonMethod =
| Contains
| Equals

type FieldValue = 
    { Name : string
    , Value :  string
    , ComparisonMethod 
    }

type WebCategoryItemFilterExpressionBody = 
| FieldValue of FieldValue

type WebCategoryItemFilterExpression =
| Single of WebCategoryItemFilterExpressionBody
| Or of list<WebCategoryItemFilterExpressionBody>
| And of list<WebCategoryItemFilterExpressionBody>

// actual graphql expression
query Q(
    $webCategoryId: Guid!,
    $itemFilter: WebCategoryItemFilterExpression,
) {
    webCategory(id: $id) {
        filteredItems(filter: $itemFilter) {
            description
            itemNo
        }
    }
}

// where filter could be: 
/*
Or([
    (Or([
        (FieldValue { Name = "field1"
                      , Value = "foo"
                      , ComparisonMethod = Equals })
        (FieldValue { Name = "field2"
                    , Value = "foo"
                    , ComparisonMethod = Equals })
    ])),
    (And([
        (FieldValue { Name = "field2"
                      , Value = "foo"
                      , ComparisonMethod = Equals })
        (FieldValue { Name = "field3"
                    , Value = "foo"
                    , ComparisonMethod = Equals })
    ]))
    (Single(FieldValue { Name = "field4"
                       , Value = "foo"
                       , ComparisonMethod = contains }))
])
*/