OneOf method generates useless code?

[antipopp]

I'm trying to use OneOf in my schema, like this

var Report = dsl.Type("Report", func() {
	dsl.Description("Report describes a generated report.")
	dsl.Attribute("workspace_id", dsl.String, "Workspace ID")
	dsl.Attribute("assets", dsl.ArrayOf(dsl.String), "Assets")
	dsl.Attribute("from", dsl.String, "From")
	dsl.Attribute("to", dsl.String, "To")

	dsl.Required("workspace_id", "assets", "from", "to")
})

var Data = dsl.Type("Data", func() {
	dsl.Description("Data describes the data needed to generate a report.")
	dsl.OneOf("forms", "Payload forms", func() {
		dsl.Attribute("report", Report, "Report")
	})
})

var Form = dsl.Type("Form", func() {
	dsl.Description("Form describes a Report that can be created or updated via the API.")
	dsl.Attribute("template_id", dsl.String, func() {
		dsl.Meta("struct:tag:json", "template_id")
	})
	dsl.Attribute("data", Data, func() {
		dsl.Meta("struct:tag:json", "data")
	})

	dsl.Required("template_id", "data")
})

There is only one type so far but if it works I plan to add others. The generated code has these structs which I cannot find a way to use:

// Data describes the data needed to generate a report.
type Data struct {
	// Payload forms
	Forms interface {
		formsVal()
	}
}

// Form describes a Report that can be created or updated via the API.
type Form struct {
	TemplateID string `json:"template_id"`
	Data       *Data  `json:"data"`
}

// GeneratePayload is the payload type of the templates service generate method.
type GeneratePayload struct {
	// Workspace ID
	WorkspaceID string
	// Form of the template
	Form *Form
}

// Report describes a generated report.
type Report struct {
	// Workspace ID
	WorkspaceID string
	// Assets
	Assets []string
	// From
	From string
	// To
	To string
}

func (*Report) formsVal() {}

How am I supposed to use it

[douglaswth]

A pointer to the Report type can be assigned to the Forms field of the Data type since it implements the interface:

data := &gen.Data{
    Forms: &gen.Report{
        WorkspaceID: "abcdef",
        Assets: []string{"a", "b", "c"},
        From: "a",
        To: "b",
    },
}

On the other side, a type switch (or a checked type assertion) can be used to determine which type a value in the Forms field of the Data type is:

switch forms := data.Forms.(type) {
case *gen.Report:
    fmt.Println(forms.WorkspaceID, forms.Assets, forms.From, forms.To)
}