[PATCH 2/3] ui: Switch "-display sdl" to use the QAPI parser

[Markus Armbruster]

Thomas Huth <thuth at redhat.com> writes:

> On 12/05/2022 14.16, Markus Armbruster wrote:

[...]

>>> This introduces the new "DisplaySDL" QAPI struct that is used to hold
>>> the parameters that are unique to the SDL display. The only specific
>>> parameter is currently "grab-mod" which is modeled as a string, so that
>>> it could be extended for other arbitrary modifiers later more easily.
>> 
>> Are the values of @grab-mod parsed in any way, or do we recognize a set
>> of fixed strings?
>> 
>> The former would be problematic.  We try hard to represent complex data
>> as JSON instead of inventing little ad hoc languages.
>> 
>> If it's the latter, use an enum.  Makes introspection more useful, and
>> adding enumeration values is no harder than adding string literals.
>
> It's currently only two strings that are used to replace the old behavior. 
> But in the long run, I think it would be nice to have more flexibility here, 
> so that a user could specify an arbitrary combination of modifier keys. I 
> don't think that an enum will really scale here, so I'd prefer to go with 
> the current approach and use the string for more flexibility.

"Arbitrary combination of modifier keys" sounds like set of enum to me.
We approximate sets with lists in QAPI.