Yesterday I was playing with some OOP stuff, including proCall. While using
procCall was working fine in my first tiny example, now for a more complex
example with initialization I get a c compiler error. The code below may be
similar to Ruby, where we generally define a initialize() method for each
class, and call super() to initialize parent class. But I haven't used OOP Ruby
in the last few years, so maybe my memory is wrong.
type
Animal* = ref object of RootObj
age*: int
proc init(x: var Animal) =
x.age = 0
method cry(x: Animal) {.base.} =
echo "Animal is silent..."
type Mammal* = ref object of Animal
legs: int
proc init(x: var Mammal) =
x.Animal.init()
x.legs = 4
method cry(x: Mammal) =
echo "Mammal is crying..."
type
Dog* = ref object of Mammal
tail: int
ears: int
proc init(x: var Dog) =
x.Mammal.init()
x.tail = 1
x.ears = 2
proc newDog(): Dog =
new result
result.init
return result
method cry(x: Dog) =
echo "Dog is barking..."
proc birthsday(x: var Dog) =
inc(x.age)
type
Cat* = ref object of Mammal
tail: int
ears: int
angry: bool
proc init(x: var Cat) =
x.Mammal.init()
x.tail = 1
x.ears = 2
x.angry = false
proc newCat(): Cat =
new result
result.init
return result
method cry(x: Cat) =
if x.angry:
echo "Cat says: Grrr..."
else:
echo "Cat says: Mmm.."
proc main =
var s = newSeq[Animal]()
let c = newCat()
c.angry = true
s.add(c)
s.add(newDog())
Dog(s[1]).birthsday()
for a in s:
a.cry()
echo "Age: ", a.age
if a of Dog:
echo "A dog with ", Dog(a). tail, "tails"
main()
Run
$ nim c t.nim
Hint: used config file '/home/stefan/Nim/config/nim.cfg' [Conf]
Hint: system [Processing]
Hint: t [Processing]
CC: t
Error: execution of an external compiler program 'gcc -c -w
-I/home/stefan/Nim/lib -o /tmp/stefan/.cache/nim/t_d/t.c.o
/tmp/stefan/.cache/nim/t_d/t.c' failed with exit code: 1
/tmp/stefan/.cache/nim/t_d/t.c: In function ‘init_hPQB9bncQO33ZGcoMQdkBKg’:
/tmp/stefan/.cache/nim/t_d/t.c:370:10: error: ‘*x’ is a pointer; did you
mean to use ‘->’?
T1_ = &x->Sup;
^~
->
/tmp/stefan/.cache/nim/t_d/t.c: In function ‘init_mSSvrmRS9bt4Nq6vrZQpYQQ’:
/tmp/stefan/.cache/nim/t_d/t.c:382:10: error: ‘*x’ is a pointer; did you
mean to use ‘->’?
T1_ = &x->Sup;
^~
->
/tmp/stefan/.cache/nim/t_d/t.c: In function ‘init_WBRfKYrhvEwtbXboHZJTMQ’:
/tmp/stefan/.cache/nim/t_d/t.c:486:10: error: ‘*x’ is a pointer; did you
mean to use ‘->’?
T1_ = &x->Sup;
^~
->
/tmp/stefan/.cache/nim/t_d/t.c: In function ‘main_r7VpEd9b9aQPUbk4pk8k4iZQ’:
/tmp/stefan/.cache/nim/t_d/t.c:615:37: error: lvalue required as unary ‘&’
operand
birthsday_WBRfKYrhvEwtbXboHZJTMQ_2(&((tyObject_DogcolonObjectType__9aSs3XCzg3yD8YNUmflsgKw*)
(s->data[((NI) 1)])));
Run
$ nim -v
Nim Compiler Version 0.18.1 [Linux: amd64]
Compiled at 2018-09-14
Copyright (c) 2006-2018 by Andreas Rumpf
git hash: 382fe446c3926f7976de09b7a1d8ad131912c7b6
active boot switches: -d:release
Run
