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4242 :: Nim source equivalent to C #define

• geezer9 (orginal) [2018-09-26T14:31:43+02:00] view original

  Is there a pragma (or some such) that performs like the C preprocessor command:

  
  #define SOMEOPTION
  Run

  I would like definition of some debugging flags to automatically define others. For example:

  
  when defined(DEPENDENTFLAG):
       {.define(NEEDEDFLAG).}
  Run

  so that NEEDEDFLAG gets automatically defined even when the nim compille command is:

  
  nim c -d:DEPENDENTFLAG somesource.nim
  Run

  Thanks

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• lotzz (orginal) [2018-09-26T14:37:00+02:00] view original

  const Thing = 0
  
  when declared(Thing):
    const otherThing = 0
  
  when declared(otherThing):
    echo "we are here"
  Run

  this works

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• juancarlospaco (orginal) [2018-09-26T15:16:14+02:00] view original

  
  {. emit: """#define SOMEOPTION""" .}
  Run

  Literal, For C target.

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• mratsim (orginal) [2018-09-26T16:24:47+02:00] view original

  I use a nim.cfg in Arraymancer:

  
  @if cudnn:
    define:"cuda"
  @end
  Run

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• lotzz (orginal) [2018-09-26T16:30:00+02:00] view original

  i just want to say, i love how many good options nim has for such a simple thing.

  Nim -- a buffet for the programmers taste

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• DeletedUser (orginal) [2018-09-26T17:41:12+02:00] view original

  One that hasn't been mentioned yet is simply:

  const NeededFlag = defined(DependentFlag)
  
  when NeededFlag:
    discard # code goes here
  Run

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• jangko (orginal) [2018-09-26T17:44:47+02:00] view original

  Actually Nim has {.define: identifier.} pragma, but then it was deprecated. I'm curious to know what was the reason. Doesn't it behave similarly with '-d:' or '--define:'?

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• geezer9 (orginal) [2018-09-27T05:07:20+02:00] view original

  Many thanks for all the suggestions.

  Since NEEDEDFLAG can also be set by:

  
  nim c -d:NEEDEDFLAG etc.etc.
  Run

  I need to use defined(NEEDEDFLAG) instead of declared(NEEDEDFLAG).

  However the following inside nim.cfg worked for me:

  
  @if BGMAP:
      define:BGDUMP
  @end
  Run

  which is the actual example in use.

  Where (URL) are the @ commands for nim.cfg documented?? I could not find them in https://nim-lang.org/docs/nimc.html

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