events.nim

import macros

type
  EventHandler*[T] = proc(event: T)
  EventStore[T] = seq[EventHandler[T]]

proc getEventStore[T](): var EventStore[T] =
  static var store = newSeq[T]()
  result = store

proc subscribe*[T](self: typedesc[T], handler: EventHandler) =
  var store = getEventStore[T]()
  store.add(handler)

proc unsubscribe*[T](self: typedesc[T], handler: EventHandler) =
  var store = getEventStore[T]()
  store.del(handler)

proc fire*[T](event: T) =
  var store = getEventStore[T]()
  for handler in store: handler(event)

signature should be proc subscribe*[T](self: typedesc[T], handler: EventHandler[T]) = I think, you might have cannot instantiate T otherwise.