func makeUserPrimitiveUnfolder()

in gotype/unfold_user.go [116:142]

• 22 lines of code
• 8 McCabe index (conditional complexity)

func makeUserPrimitiveUnfolder(fn reflect.Value) (reflUnfolder, error) {
	t := fn.Type()

	if fn.Kind() != reflect.Func {
		return nil, errors.New("function type required")
	}

	if t.NumIn() != 2 {
		return nil, fmt.Errorf("function '%v' must accept 2 arguments", fn)
	}
	if t.NumOut() != 1 || (t.NumOut() > 0 && t.Out(0) != tError) {
		return nil, fmt.Errorf("function '%v' does not return errors", fn)
	}

	ta0 := t.In(0)
	if ta0.Kind() != reflect.Ptr {
		return nil, fmt.Errorf("first argument in function '%v' must be a pointer", t.Name())
	}

	constr := lookupUserPrimitiveConstructor(t.In(1))
	if constr == nil {
		return nil, fmt.Errorf("%v is no supported primitive type", t.In(1))
	}

	unfolder := constr(fn)
	return liftGoUnfolder(unfolder), nil
}