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5880 :: Template with dirty pragma within an async context

• Dankrad (orginal) [2020-02-03T01:35:01+01:00] view original

  Hi,

  I've got a problem when using the dirty pragma within an async context. I want to "inject" a templates body into a procedure for less typing. If there's an error, the template should handle this error and return within the handleJoin proc.

  Could this be an unsolveable issue, when using async? As far as I know the async pragma is not allowed with templates.

  Example:

  # [...]
  proc responseError(req: Request, error: MatchError): Future[void] {.async.} =
    await req.respond(Http400, $error)
  
  template handleError(error: untyped): untyped {.dirty.} =
    if error.isError:
      case req.reqMethod
      of HttpGet:
        await req.responseError(error)
      else:
        raise newException(ValueError, "Currently only GET is supported!")
      return # <-- This should prevent executing code after the handleError call
  
  proc handleJoin(req: Request): Future[void] {.async.} =
    var (error, match) = getMatch()
    handleError(error)
    # Some other code which should not be executed when there's an error.
  
  # [...]
  Run

  It fails with:

  
  Error: Await only available within .async
  Run

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• juancarlospaco (orginal) [2020-02-03T02:26:46+01:00] view original

  Change template to proc with async and inline ?.

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• Dankrad (orginal) [2020-02-03T02:39:32+01:00] view original

  I've tried that too (and retried it now). But when I change the templat to a proc with inline and async pragma, the code after handleError will be executed. I think the return keyword will only affect handleError and not handleJoin.

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