[Python-Dev] PEP 7 clarification request: braces

Benjamin Peterson benjamin at python.org
Mon Jan 2 15:54:02 CET 2012

2012/1/1 Nick Coghlan <ncoghlan at gmail.com>:
> I've been having an occasional argument with Benjamin regarding braces
> in 4-line if statements:

Python's C code has been dropping braces long before I ever arrived.
See this beautiful example in dictobject.c, for example:

    if (numfree < PyDict_MAXFREELIST && Py_TYPE(mp) == &PyDict_Type)
        free_list[numfree++] = mp;
        Py_TYPE(mp)->tp_free((PyObject *)mp);

There's even things like this:

    if (ep->me_key == dummy)
        freeslot = ep;
    else {
        if (ep->me_hash == hash && unicode_eq(ep->me_key, key))
            return ep;
        freeslot = NULL;

where I would normally put braces on both statements.

I think claims of its maintainability are exaggerated. (If someone
could cite an example of a bug caused by braces, I'd be interested to
see it.) If I start editing one of the bodies, emacs will dedent, so
that I know I'm back to the containing block. By virtue of being 5
lines long, it's a very easy case to see and fix as you edit it.

I think it's fine Nick raised this. PEP 7 is not very explicit about
braces at all.


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