Re: Another take on versioning

"Henry S. Thompson" <ht@inf.ed.ac.uk> writes:
> [anon] writes:
>
>>> OK, so we need wording that says that if a pipeline contains a step
>>> that it doesn't recognise (eg the v2 step in the above) then it must
>>> not run any steps in the pipeline. Right? But that's a separate issue.
>>
>> Right.
>
> No, wrong -- only a problem if it has to _run_ that step.  We've
> already agreed that, I thought.

Right, sorry. Though if it contains an unguarded use of that step,
it's not clear to me what it should do:

  <p:pipeline>
     <p:identity ...>
     <p:split-sequence ...>
     <p:defined-in-V.next ...>

The implementation design I have in my head right now is going to
percolate the invalid step up to the top-level pipeline and then
refuse to even start running it.

Of course, if that was in p:choose/p:when, the situation would be
different.

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | He who fails to become a giant need not
http://nwalsh.com/            | remain content with being a
                              | dwarf.--Ernest Bramah