Yes, 'any' is a generic (typeclass). Your object should probably be defined
like this
type item[T] = object
value: T
next: ptr item[T]
Likewise '<' is an overloaded proc, so not a specific proc that you can pass to
a function. Also, you don't need to specify 'ptr' for a proc when used as an
argument, Nim will implicitly do the right thing for the corresponding backend.
You can wrap overloaded functions in a specific one if you want to pass them
proc a(p: proc) =
var x,y: int
echo p(x,y)
proc lt(x,y: int): bool =
x < y
a(lt)
or you can use a template to generate separate functions for each proc you want
passed in. This can then handle overload procs.
template makeproc(f,p: untyped): untyped =
proc f =
var x,y: int
echo p(x,y)
makeproc(b, `<`)
b()
