All clr objects are stored as [variant](https://khchen.github.io/winim/com.html#variant) in nim. And it just a wrap of [win32 VARIANT](https://docs.microsoft.com/en-us/windows/win32/api/oaidl/ns-oaidl-variant) .
To distinguish com variant from clr variant, clr.nim defines [following types](https://khchen.github.io/winim/clr.html#CLRType). type CLRType = distinct variant CLRVariant = distinct variant Run So, they are all the same in fact. The only difference is that CLRVariant uses instance binding to invoking a member, and CLRType uses static binding. However, all return type of clr operation are CLRVariant. For convenience, `@` operator can be used to convert some CLRVariant into CLRType for static binding. In your example, `IWorkbook.GetType()` returned an object of .net Type class and stored as CLRVariant in nim, so it cannot be used as type definition. If you want to define some variant before using them, you can use `var workbook: CLRVariant`. You can also use nim's magic [type](https://nim-lang.org/docs/system.html#type) to see what shoud you use. For example: proc test(): int = discard echo test().type # int var i: test().type t = test() echo clr.load("mscorlib").type # CLRVariant Run
