I have just read PEP 7 and noticed that its line-breaking recommandation in presence of binary operations seems to contradict its analogue in PEP 8 which follows Knuth's rule.

PEP 7 (https://www.python.org/dev/peps/pep-0007/#code-lay-out):

> When you break a long expression at a binary operator, the operator
> goes at the end of the previous line, and braces should be formatted
> as shown. E.g.:
> 
> 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 */
> }

PEP 8 (https://www.python.org/dev/peps/pep-0008/#should-a-line-break-before-or-after-a-binary-operator):

> To solve this readability problem, mathematicians and their
> publishers follow the opposite convention. Donald Knuth explains the
> traditional rule in his Computers and Typesetting series: "Although
> formulas within a paragraph always break after binary operations and
> relations, displayed formulas always break before binary operations"
> [3].
> 
> Following the tradition from mathematics usually results in more
> readable code:
> 
> # Yes: easy to match operators with operands
> income = (gross_wages
>           + taxable_interest
>           + (dividends - qualified_dividends)
>           - ira_deduction
>           - student_loan_interest)
> In Python code, it is permissible to break before or after a binary
> operator, as long as the convention is consistent locally. For new
> code Knuth's style is suggested.

I personally don't think we need to change this.  C and Python are different, and the PEP 7 rules have been in place for ages.

+Guido

PEP 8 contains contradictory examples.

https://www.python.org/dev/peps/pep-0008/#indentation

>     # No extra indentation.
>     if (this_is_one_thing and
>         that_is_another_thing):
>         do_something()
> 
>     # Add a comment, which will provide some distinction in editors
>     # supporting syntax highlighting.
>     if (this_is_one_thing and
>         that_is_another_thing):
>         # Since both conditions are true, we can frobnicate.
>         do_something()
> 
>     # Add some extra indentation on the conditional continuation line.
>     if (this_is_one_thing
>             and that_is_another_thing):
>         do_something()
> 
> (Also see the discussion of whether to break before or after binary
> operators below.)

(It was already reported in other issue.)

PEP 8 intentionally allows users to choose whether to put the operator at the start or end of the line (as long as they're consistent within a file or project). This is to avoid a barrage of "style fixes" that are just noise.

But PEP 7 is only for CPython's own C code style, and here I don't want things to change. When it comes to readability of our code surely there are bigger fish to fry.

So I'm closing this as won't fix.