Re: Detecting errors

On Thu, Oct 9, 2008 at 1:11 PM, Josh Matthews <joshmatthews@gmail.com>wrote:

> On Thu, Oct 9, 2008 at 8:14 AM, Norman Walsh <ndw@nwalsh.com> wrote:
>
>> Consider the following pipeline:
>>
>> <p:declare-step name="main" ...>
>>  <p:input port="source"/>
>>  <p:output port="source"/>
>>
>>  <p:declare-step type="px:unused">
>>    <p:input port="source"/>
>>    <p:output port="source"/>
>>    <px:undeclared/>
>>  </p:declarestep>
>>
>>  <p:identity/>
>> </p:declare-step>
>>
>> (a) Does this pipeline contain an error?
>> (b) Are implementations allowed to report it?
>> (c) Are implementations required to report it?
>>
>
> I think the answer to both is no.
>

To be clear(er), I should clarify that I think the answer to _all_ (a, b,
and c) is no.


> There is no static error that can catch this, and the only dynamic error
> that comes close is XD0017 ("It is a dynamic error if the running pipeline
> attempts to invoke a step which the processor does not know how to
> perform."). In this case, however, the running pipeline does not attempt to
> invoke the declared step that contains the undeclared step (I assume that is
> what you intended by naming the step "px:unused") - so no error occurs.
>
> There is no error to report, so it is not required nor allowed.
>
> Cheers,
> Josh Matthews
>