"Generally, mixed-mode arithmetic combining real and complex variables should
be performed directly, not by first coercing the real to complex, lest the sign
of zero be rendered uninformative; the same goes for combinations of pure
imaginary quantities with complex variables." (c) Kahan, W: Branch cuts for
complex elementary functions.
This patch implements mixed-mode arithmetic rules, combining real and
complex variables as specified by C standards since C99 (in particular,
there is no special version for the true division with real lhs
operand). Most C compilers implementing C99+ Annex G have only these
special rules (without support for imaginary type, which is going to be
deprecated in C2y).
To recap: the objective is to make starred expressions valid in `subscription`,
which is used for generics: `Generic[...]`, `list[...]`, etc.
What _is_ gramatically valid in such contexts? Seemingly any of the following.
(At least, none of the following throw `SyntaxError` in a 3.12.3 REPL.)
Generic[x]
Generic[*x]
Generic[*x, y]
Generic[y, *x]
Generic[x := 1]
Generic[x := 1, y := 2]
So introducting
flexible_expression: expression | assignment_expression | starred_item
end then switching `subscription` to use `flexible_expression` sorts that.
But then we need to field `yield` - for which any of the following are
apparently valid:
yield x
yield x,
yield x, y
yield *x,
yield *x, *y
Introducing a separate `yield_list` is the simplest way I've been figure out to
do this - separating out the special case of `starred_item ,`.
Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
gh-111944: Clarify where assignment expressions require ()s
Augment the list of places where parentheses are
required around assignnment statements. In particular,
'a := 0' and 'a = b := 1' are syntax errors.
* Uncomment object removal in pairindextypes
* Use new-style index directive ('object') - C API
* Use new-style index directive ('object') - Library
* Use new-style index directive ('object') - Reference
* Use new-style index directive ('object') - Tutorial
* Add walrus operator to the index
* Add named expression to the index
Co-authored-by: Mariatta Wijaya <Mariatta@users.noreply.github.com>
* Fix indentation and add missing newline
Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>
Co-authored-by: Mariatta Wijaya <Mariatta@users.noreply.github.com>
Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>
Keep track of whether unsafe_tuple_compare() calls are resolved by the very
first tuple elements, and adjust strategy accordingly. This can significantly
cut the number of calls made to the full-blown PyObject_RichCompareBool(),
and especially when duplicates are rare.
Co-authored-by: Łukasz Langa <lukasz@langa.pl>
sobolevn