Method walkFilterFunc

datasource/sqlite/sqlrewrite.go:335–344

Take an expression func, ensure we don't do runtime-checking (as the function) doesn't really exist, then map that function to a mongo operation exists(fieldname) regex(fieldname,value)

(node *expr.FuncNode)

//    regex(fieldname,value)
//
func (m *rewrite) walkFilterFunc(node *expr.FuncNode) (expr.Node, error) {
	switch funcName := strings.ToLower(node.Name); funcName {
	case "exists", "missing":

	default:
		u.Warnf("not implemented %T", funcName)
	}

	return node, nil
}

// Take an expression func, ensure we don't do runtime-checking (as the function)
// doesn't really exist, then map that function to an Mongo Aggregation/MapReduce function