Afaik, OOP (for example in Java) still need which method can be override, which
final, which abstract method(/class).
If the author didn't set those info, nothing for lib's users able to override
or do anything the original lib.
Actually you're incorrect that a proc can be redefined across module because
each proc defined with different module has symbol name as
module_name.proc_name, so if there's two procs that has same arity and
parameters types, compiler will report the error unless you call it full the
proc symbol.
This is how you do it with closure
#heroes.nim
type
Hero* = ref object of RootObj
ImplementationError* = object of Exception
method kill*(self, victim: Hero, howItKilled: proc(casualty: Hero) = nil) =
if howItKilled.isNil:
raise newException(ImplementationError,
"Hero descendants should describe how they're killed")
else:
howItKilled victim
#jedi.nim
import heroes
type
OB1* = ref object of Hero
Yoda* = ref object of Hero
method kill*(self: Hero, ob1: OB1,
howItKilled = (proc(victim: OB1) =
echo "Obi Wan Kenobi was Killed")) =
howItKilled ob1
method kill*(self: Hero, yoda: Yoda,
howItKilled = (proc(victim: Yoda) =
echo "Obi Wan Kenobi was Killed")) =
howItKilled yoda
#main.nim
import heroes
import jedi
let
darthVader = new Hero
yoda = new Yoda
try:
darthVader.kill(cast[Hero](yoda), howItKilled=nil)
except ImplementationError:
echo getCurrentExceptionMsg()
darthVader.kill yoda # call with default defined closure
darthVader.kill(yoda, howItKilled=(proc(yoda: Yoda) = echo "Yoda may not be
killed"))
