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4618 :: Custom assignment operator

• jacobsin (orginal) [2019-02-02T08:08:42+01:00] view original

  I realize what I am asking is "Dark magic" and goes against what should be done. However, with that in mind I would like to create a custom assignment operator.

   var x:int =5
  Run

  vs.

   var x <| 5
  Run

  or

   var x << 5
  Run

  What I have tried so far...

   template `<<` (a, b: untyped): untyped =
      system.`=`(a, b)
  
  var a:int
  a << 5
  echo a
  Run

  The above code works but,

   var a << 5
  Run

  But the error I get back is:

   index.nim(9, 11) Error: type mismatch: got <type int, int literal(5)>
  but expected one of:
  proc `=`[T](dest: var T; src: T)
    first type mismatch at position: 1
    required type: var T
    but expression 'int' is of type: type int
  
  expression: `=`(int, 5)
  Run

  Hope this is possible but honestly not sure. Mind you im only barely getting into Nim so expect some really dumb questions :/

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• juancarlospaco (orginal) [2019-02-02T10:19:14+01:00] view original

  But you dont need var x:int =5 just var x = 5. 🤔

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• mratsim (orginal) [2019-02-04T11:34:23+01:00] view original

  Related to Nim syntax skins? https://forum.nim-lang.org/t/2811

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• konradmb (orginal) [2019-02-16T15:28:50+01:00] view original

  Try with Source Code Filters

  #? replace(sub="<<", by="=")
  
  var a << 5
  echo a
  Run

  But that's an ugly hack. 😊

  Everything that's a << becomes =, so echo "This is <<" outputs This is = .

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