[Python-Dev] Update PEP 7 to require curly braces in C

[Jim J. Jewett]

> On Jan 17, 2016, at 11:10, Brett Cannon <brett at python.org> wrote:

>> While doing a review of http://bugs.python.org/review/26129/ 
>> ... update PEP 7 to remove the optionality of curly braces

On Mon Jan 18 03:39:42 EST 2016, Andrew Barnert pointed out:

> There are two ways you could do that.

[The one most people are talking about, which often makes an if-clause
visually too heavy ... though Alexander Walters pointed out that
"Any excuse to break code out into more functions... is usually the
right idea."]

    if (!obj) {
        return -1;
    }


> Alternatively, it could say something like "braces must not be omitted;
> when other C styles would use a braceless one-liner, a one-liner with
> braces should be used instead; otherwise, they should be formatted as follows"

That "otherwise" gets a bit awkward, but I like the idea.  Perhaps
"braces must not be omitted, and should normally be formatted as
follows. ... Where other C styles would permit a braceless one-liner,
the expression and braces may be moved to a single line, as follows: "

    if (x > 5) { y++ }

I think that is clearly better, but it may be *too* lightweight for
flow control.

    if (!obj)
        { return -1; }

does work for me, and I think the \n{} may actually be useful for
warning that flow control takes a jump.


One reason I posted was to point to a specific example already in PEP 7
itself:

    if (type->tp_dictoffset != 0 && base->tp_dictoffset == 0 &&
        type->tp_dictoffset == b_size &&
        (size_t)t_size == b_size + sizeof(PyObject *))
        return 0; /* "Forgive" adding a __dict__ only */

For me, that return is already visually lost, simply because it shares
an indentation with the much larger test expression.  Would that be
better as either:

    /* "Forgive" adding a __dict__ only */
    if (type->tp_dictoffset != 0 && base->tp_dictoffset == 0 &&
        type->tp_dictoffset == b_size &&
        (size_t)t_size == b_size + sizeof(PyObject *)) { return 0; }

or:

    /* "Forgive" adding a __dict__ only */
    if (type->tp_dictoffset != 0 && base->tp_dictoffset == 0 &&
        type->tp_dictoffset == b_size &&
        (size_t)t_size == b_size + sizeof(PyObject *)) {
            return 0;
        }
        
-jJ

--

If there are still threading problems with my replies, please
email me with details, so that I can try to resolve them.  -jJ