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437 :: How to get the function type variable's value?

• donydh (orginal) [2014-05-01T15:08:03+02:00] view original

  proc test(a:int,b:int):int=

  result = a+b

  type

  fn = object

  p : proc (x:int,y:int):int

  var v:fn v.p= test echo v.p(2,3) echo v.p #How to get this value?

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• Jehan (orginal) [2014-05-01T15:50:47+02:00] view original

  Well, v.p will get you the value. However, v.p is a closure type, which cannot really be printed using echo (internally, it's a pair containing a pointer to the function and a pointer to the environment).

  If you want to just look at the address of the function inside (say, for debugging purposes), the following should work:

  
  proc test(a: int, b: int): int =
    result = a+b
  
  type
    fn = object
      p: proc (x: int, y: int): int {.nimcall.}
  
  var v: fn
  v.p = test
  echo v.p(2, 3)
  echo cast[uint](v.p)
  echo cast[uint](test)
  Run

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• Araq (orginal) [2014-05-01T16:14:53+02:00] view original

  There is system.rawProc and system.rawEnv to get the underlying components of a closure's tuple.

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• Varriount (orginal) [2014-05-01T17:54:07+02:00] view original

  Also, don't forget the built-in repr() procedure. For 99% of cases, repr() will return a sensible string representation of it's argument. x.repr.echo will print out the representation.

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