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508 :: Object Properties and Cloning

• fuzzthink (orginal) [2014-07-26T00:34:29+02:00] view original

  Is there a way to list out properties of an object? Is there a way to assign them to a new object?

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• Jehan (orginal) [2014-07-26T00:55:22+02:00] view original

  Yes, you can use system.fieldPairs:

  
  type T = object
    a, b: int
  
  var ob: T
  for a, b in fieldPairs(ob):
    echo a, " ", b
  Run

  Note that the for loop isn't actually compiled to a loop. It'll be unrolled once for each object field, and you can then use when or overloading to choose a different implementation for a field name or type. See the system.nim code for an example how that can be done.

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• gradha (orginal) [2014-07-26T01:12:50+02:00] view original

  The when example is in the development docs. With regards to assigning the values, can't you do x = a?

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• Araq (orginal) [2014-07-26T10:39:27+02:00] view original

  The yielded fields are lvalues (we should update the documentation to mention this), so yes you can assign to them.

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• fuzzthink (orginal) [2014-07-27T04:26:30+02:00] view original

  Does nimrod have something like javascript's obj[name] = val, or python's setattr(obj, name, val) syntax? Otherwise, I still won't be able to use fieldPairs to implement a generic cloning proc.

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• Jehan (orginal) [2014-07-27T10:30:32+02:00] view original

  See marshal.nim for an example how you can use RTTI to deconstruct/construct Nimrod objects if you need something truly generic (typeinfo.nim contains the relevant API).

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