On 08/07/2017 05:30 PM, Pavel Hrdina wrote:
> On Mon, Aug 07, 2017 at 05:06:49PM +0200, Michal Privoznik wrote:
>> On 08/07/2017 04:56 PM, Ján Tomko wrote:
>>> Make the comparison explicit.
>>> ---
>>> src/conf/domain_conf.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
>>> index 3cdb5e348..b5ce2ecd9 100644
>>> --- a/src/conf/domain_conf.c
>>> +++ b/src/conf/domain_conf.c
>>> @@ -5359,10 +5359,10 @@ virDomainDeviceInfoFormat(virBufferPtr buf,
>>> }
>>>
>>> if ((flags & VIR_DOMAIN_DEF_FORMAT_ALLOW_ROM) &&
>>> - (info->rombar || info->romfile)) {
>>> + (info->rombar != VIR_TRISTATE_SWITCH_ABSENT || info->romfile)) {
>>>
>>> virBufferAddLit(buf, "<rom");
>>> - if (info->rombar) {
>>> + if (info->rombar != VIR_TRISTATE_SWITCH_ABSENT) {
>>> const char *rombar = virTristateSwitchTypeToString(info->rombar);
>>>
>>> if (rombar)
>>>
>>
>> I'm not against this patch, it's just that we set ABSENT explicitly to
>> zero value so that we can do shortcuts like this. If we don't want to
>> have them, we ought to remove the explicit value assignment.
>
> The shortcut is nice, but I don't like it personally. If the variable
> can contain more than two states I'd rather check it explicitly.
So what's the point of assigning _ABSENT zero value then?
> That's
> why I prefer (int == 0) over (!int).
Well, if this is a part of bigger statement then yes, for instance:
if (x == 0) {
} else if (x == 1) {
} else {
}
(although, sometimes we might prefer switch() for that). But if it's
just a simple check whether a value was set or is equal to some default
(= if the check is interested in distinguishing just two states anyway),
!var works for me too:
if (x)
formatToXML(x)
But sure, var == 0 vs !var is a personal preference. The important part
is my first question. If we dislike these shortcuts (in either of their
form), shouldn't we just drop explicit value assignment in the enum?
Michal
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