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3694 :: Reflection and JSON decoding

• diegogub (orginal) [2018-03-27T10:09:04+02:00] view original

  Hello,

  I have a stream of events, each event has a type field as string and data.

  I'm a Go programmer, and Im using reflection / interfaces{} to parse the events into correct type.

  How would you do it in Nim. In Go basically I have map of strings and type of event, and use reflection to parse into correct type.

  Also I do a case on type of event.

  Regards

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• mashingan (orginal) [2018-03-27T12:47:43+02:00] view original

  For newest stable version (0.18.0), there macro to defined here https://nim-lang.org/docs/json.html#to.m,JsonNode,typedesc

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• dom96 (orginal) [2018-03-27T12:49:42+02:00] view original

  There are two ways, by dynamically accessing each field as described here or by using the to macro: https://nim-lang.org/docs/json.html#to.m,JsonNode,typedesc

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• diegogub (orginal) [2018-03-27T13:31:05+02:00] view original

  Thanks, that works..Also what I normally use in Golang is :

  
          switch v := i.(type) {
          case int:
                  fmt.Printf("Twice %v is %v\n", v, v*2)
          case string:
                  fmt.Printf("%q is %v bytes long\n", v, len(v))
          default:
                  fmt.Printf("I don't know about type %T!\n", v)
          }
  Run

  Also, Should I use templates for this?.. I have quite big case statments sometimes.

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• mashingan (orginal) [2018-03-27T17:06:57+02:00] view original

  I don't know your use case, but if I have to guess, you don't have to.

  If you only need a field or two, you can just retrieve the fields you need.

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