Re: qmp-shell for GSoC/Outreachy?

[Eric Blake <eblake@redhat.com>]

On 2/6/20 12:18 PM, Dr. David Alan Gilbert wrote:

>>
>> Pain points of JSON include having to count parenthesises and having to
>> quote so bloody much.  Additional QMP pain points include long names and
>> excessive nesting.
> 
> Some other pet hates:
>    a) Number formats are awful for our uses
>    b) Lack of room for comments

Both permitted in JSON5.  Converting valid JSON5 into the stricter JSON 
is lossy when it comes to comments, but as comments don't affect machine 
meaning, maybe all the more it requires is an argument to 
qmp_capabilities stating whether the rest of the session will stick to 
strict JSON or prefer JSON5.

>> We could make quoting optional for certain string literals.

Hmm - JSON5 makes quoting optional for keys in { key:value }, but not 
values.

And one of the reasons why my QAPIfication of netdev was NOT committed 
was that the original code allowed both "item":1 and "item":"1" in the 
QemuOpts world, and we were torn on whether letting QMP accept both 
integer and string-that-parses-as-integer was acceptable.

>>  Simple
>> enough for literals that can only be a string, like abc.  For literals
>> that could be something else like 123 or true, omitting quotes creates
>> ambiguity.  When the schema accepts only one of the possible types, the
>> ambiguity goes away.  Complexity stays, however.

Do we even allow an alternate that permits both a string and a number at 
once? I thought you tightened qapi to reject that because of the 
potential for ambiguity.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org