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898 :: Unmarshalling data issue

• owl (orginal) [2015-02-19T21:56:49+01:00] view original

  Hello,

  I'm trying to use marshal module to marshal and unmarshal some data. My code looks like this:

  
  import marshal
  
  type
    Foo = object of RootObj
      id: int
      bar: string
  
  let x = Foo(id: 1, bar: "baz")
  let y = ($$ x)
  let z = y.to[Foo]
  Run

  When I try to compile this, I get a type error:

  
  m.nim(10, 9) Info: instantiation from here
  lib/pure/marshal.nim(245, 38) Error: type mismatch: got (T)
  but expected one of:
  typeinfo.toAny(x: var T): TAny
  Run

  What is needed for the type to be unmarshalable?

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• owl (orginal) [2015-02-19T23:02:44+01:00] view original

  However, this form is working:

  
  let z = to[Foo](y)
  Run

  Aren't these two equivalent?

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• Araq (orginal) [2015-02-19T23:18:53+01:00] view original

  No, they are not, but it's a common gotcha that needs to be addressed, one way or the other.

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