Kevin Wolf <kw...@redhat.com> writes:
> Am 21.05.2014 um 09:46 hat Markus Armbruster geschrieben:
>> Fam Zheng <f...@redhat.com> writes:
>>
>> > On Wed, 05/21 07:54, Markus Armbruster wrote:
>> >> Fam Zheng <f...@redhat.com> writes:
>> >>
>> >> > On Tue, 05/20 13:13, Eric Blake wrote:
>> >> >> On 05/20/2014 03:07 AM, Fam Zheng wrote:
>> >> >> > Please first take a look at patch 7 to see what is supported by this
>> >> >> > series.
>> >> >> >
>> >> >> > Patch 1 ~ 3 allows some useful basic types in schema.
>> >> >> >
>> >> >> > Patch 4 ~ 6 implements the new syntax.
>> >> >> >
>> >> >> > Note: The introduced '@arg' sigil, just like the preexisting '*arg',
>> >> >> > is
>> >> >> > reducing the cleanness of the syntax. We should get rid of both of
>> >> >> > them in long
>> >> >> > term. Here, this series compromises on this and introduces '@arg'
>> >> >> > because:
>> >> >> >
>> >> >> > - We have to distinguish the argument property dictionary from
>> >> >> > nested struct:
>> >> >> >
>> >> >> > I.e.:
>> >> >> >
>> >> >> > 'data': {
>> >> >> > 'arg1': { 'member1': 'int', 'member2': 'str' }
>> >> >> > '@arg2': { 'type': 'int', 'default': 100 }
>> >> >> > }
>> >> >> >
>> >> >> > Until we completely drop and forbid the 'arg1' nested struct use
>> >> >> > case.
>> >> >> >
>> >> >> > - Forbidding 'arg1' it's doable, but doing it now means we pull in
>> >> >> > many
>> >> >> > distractive patches to this series.
>> >> >>
>> >> >> Question - since we WANT to get rid of nested struct, why not reverse
>> >> >> the sense? Mark all existing nested structs (weren't there just three
>> >> >> that we found?) with the '@' sigil, and let the new syntax be
>> >> >> sigil-free. Then when we clean up the nesting, we are also getting rid
>> >> >> of the bad syntax, plus the sigil gives us something to search for in
>> >> >> knowing how much to clean up. But if you stick the sigil on the new
>> >> >> code, instead of the obsolete code, then as more and more places in the
>> >> >> schema use defaults, it gets harder and harder to remove the use of the
>> >> >> sigil even if the nested structs are eventually removed.
>> >> >>
>> >> >
>> >> > It makes not much difference I can see. The hard part is
>> >> > actaully dropping
>> >> > nested, converting from sigil <-> non-sigil is easy. Of course,
>> >> > nothing is
>> >> > seriously hard, there are only three nested structs plus some more
>> >> > qapi-schema
>> >> > test code.
>> >>
>> >> Adding three ugly sigils and making everybody include one when they add
>> >> a nested struct feels much better to me than ugly sigils all over the
>> >> place.
>> >
>> > Well, I could use some background here. Why did we introduce
>> > nested structure
>> > in the first place?
>>
>> Because we could?
>>
>> Felt like a good idea at the time?
>>
>> I quick glance at commit 0f923be and fb3182c suggests they have been
>> supported since the beginning. There is no design rationale.
>
> Let me extend Fam's question: Why don't we simply remove them right
> now? If it's really only three instances, converting them to full
> types should be a matter of five minutes.
Trades some convenience of expresssion we haven't found useful all that
often for simplicity.
I take the simplicity.
