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1116 :: Error: 'yield' cannot be used within 'try' in a non-inlined iterator

• l04m33 (orginal) [2015-04-10T05:09:10+02:00] view original

  I've got some code like this:

  try:
      var fileContent = await transfer.reader.read(8192)
      while fileContent.len() > 0:
          totalLen += fileContent.len()
          await c.writer.write(fileContent)
          fileContent = await transfer.reader.read(8192)
  except:
      debug("transfer failed, message = $#" % [getCurrentExceptionMsg()])
      exc = getCurrentException()
  Run

  And the compiler is telling me the await c.writer.write(fileContent) line had a problem:

  Error: 'yield' cannot be used within 'try' in a non-inlined iterator

  What exactly does the error message mean?

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• Araq (orginal) [2015-04-10T16:18:04+02:00] view original

  Async/await is implemented as a macro and doesn't perform this check yet so after the transformation 'await' becomes 'yield' and the compiler tells you 'yield' cannot work in 'try' for implementation reasons. You need to do your error checking differently, async docs should tell you how.

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• dom96 (orginal) [2015-04-10T20:45:24+02:00] view original

  Async/await should support this and if it doesn't work with the latest compiler then there is a bug somewhere. Perhaps you are using 0.10.2?

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• l04m33 (orginal) [2015-04-11T06:18:56+02:00] view original

  @dom96 I was using 15b5f52 from the devel branch.

  My other await lines in try blocks can compile with no problem, just this one in a while block failed.

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• l04m33 (orginal) [2015-04-11T11:21:29+02:00] view original

  I changed the code to have only one await in the try block, and it compiled.

  var fileContent = await transfer.reader.read(8192)
  while fileContent.len() > 0:
      totalLen += fileContent.len()
      
      try:
          await c.writer.write(fileContent)
      except:
          debug("transfer failed, message = $#" % [getCurrentExceptionMsg()])
          exc = getCurrentException()
      
      fileContent = await transfer.reader.read(8192)
  Run

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• dom96 (orginal) [2015-04-11T12:49:07+02:00] view original

  Could you report that as a bug on github?

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• l04m33 (orginal) [2015-04-12T07:06:36+02:00] view original

  No problem, here you are https://github.com/Araq/Nim/issues/2528

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