On 06/14/2016 07:24 AM, Markus Armbruster wrote: > Eric Blake <[email protected]> writes: > >> We were previously enforcing that all flat union branches were >> found in the corresponding enum, but not that all enum values >> were covered by branches. The resulting generated code would >> abort() if the user passes the uncovered enum value. >> >> Signed-off-by: Eric Blake <[email protected]> > > I'd let the cases not mentioned default to the empty type (ample > precedence in other languages), but I can live with making the user ask > for the empty type explicitly. But we should then make that less > cumbersome than now: you have to define an empty struct type, and use > that. Examples of such hoop-jumping: CpuInfoOther, Abort, > NetdevNoneOptions.
Later in the series, I do just that, so that we can write 'other':{}
instead of 'other':'CpuInfoOther'.
What I did not do (but maybe should) is make that short syntax possible
on simple unions (so that we could do 'abort':{} rather than
'abort':'Abort') - and merely distinguish that simple unions cannot
stick anything within the {}, thus leaving non-empty anonymous branches
only for discriminated unions. Can do that as a followup or if this
series needs a respin.
>
> Patch looks good.
>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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