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9675 :: Ideas about the exception-tracing system

• sls1005 (orginal) [2022-11-29T13:18:32+01:00] view original

  Consider the following code:

  proc f(callback: proc()) {.raises: [].} =
    callback()
  
  proc g() {.raises: [ValueError].} =
    raise newException(ValueError, "")
  
  f(g)
  Run

  This incorrect, as f does raise an exception, but above code compiles because whether f invokes g cannot be determined at the compile-time. We cannot mark f as {.raises: [].}, nor can we mark it as raising something, because we don't know what kind of exceptions the callback will raise.

  My suggestion is to interduce a concept named SomeException

  type SomeException = concept x
    x of Exception
  Run

  Then we can mark f as {.raises: [SomeException].} to mean that "this proc can raise an exception

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• shirleyquirk (orginal) [2022-11-29T14:09:23+01:00] view original

  This is what effectsOf is for:

  proc f(callback: proc()) {.effectsOf:callback.} =
    
    callback()
  
  proc g() {.raises: [ValueError].} =
    
    raise newException(ValueError, "")
  
  proc h(){.raises:[].} =
    f(g)
  Run

  does not compile because f(g) raises

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