Re: strange case of "if ((a & b))"

Peter Smith <smithpb2250(at)gmail(dot)com> writes:
> On Thu, Aug 19, 2021 at 4:29 AM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
>> - state->oneCol = (origTupdesc->natts == 1) ? true : false;
>> + state->oneCol = origTupdesc->natts == 1;

FWIW, I am definitely not a fan of removing the parentheses in this
context, because readers might wonder if you meant an "a = b = 1"
multiple-assignment, or even misread it as that and be confused.
So I'd prefer

state->oneCol = (origTupdesc->natts == 1);

In the context of "return (a == b)", I'm about neutral on whether
to keep the parens or not, but I wonder why this patch does some
of one and some of the other.

I do agree that "x ? true : false" is silly in contexts where x
is guaranteed to yield zero or one. What you need to be careful
about is where x might yield other bitpatterns, for example
"(flags & SOMEFLAG) ? true : false". Pre-C99, this type of coding
was often *necessary*. With C99, it's only necessary if you're
not sure that the compiler will cast the result to boolean.

regards, tom lane