* Replace external recipe link with a link to the dataclasses module.
* Highlight the class definition syntax for typing.NamedTuple
and add an example for clarity.
This adds a `feature_version` flag to `ast.parse()` (documented) and `compile()` (hidden) that allow tweaking the parser to support older versions of the grammar. In particular if `feature_version` is 5 or 6, the hacks for the `async` and `await` keyword from PEP 492 are reinstated. (For 7 or higher, these are unconditionally treated as keywords, but they are still special tokens rather than `NAME` tokens that the parser driver recognizes.)
https://bugs.python.org/issue35975
Methods are always bound, and `__self__` can no longer be `NULL`
(`method_new()` and `PyMethod_New()` both explicitly check for this).
Moreover, once a bound method is bound, it *stays* bound and won't be re-bound
to something else, so the section in the datamodel that talks about accessing
an methods in a different descriptor-binding context doesn't apply any more in
Python 3.
Use UTF-8 as the system encoding on VxWorks.
The main reason are:
1. The locale is frequently misconfigured.
2. Missing some functions to deal with locale in VxWorks C library.
It is changed from 16KiB to 64KiB. The previous default value
is used since 1990.
coreutils chose 128 KiB as minimum buffer size for block device I/O.
But shutil.copyfileobj() can be used for non block devices.
So I choose more conservative value.
As my quick benchmark, performance difference between 64KiB and
128 KiB is up to ~5%. On the other hand, performance difference
between 32 KiB and 64 KiB can be more than 10% when file is fully
buffered.
This is why 64 KiB is rational value.
Responding to suggestions on the tracker and some off-line suggestions.
Davin suggested that english named accessors instead of greek letters would result in more intelligible user code. Steven suggested that the parameters still need to be *mu* and *theta* which are used elsewhere (and I noted those parameter names are used in linked-to resources).
Michael suggested proving-out the API by seeing whether it generalized to *Lognormal*. I did so and found that Lognormal distribution parameters *mu* and *sigma* do not represent the mean and standard deviation of the lognormal distribution (instead, they are for the underlying regular normal distribution).
Putting these ideas together, we have NormalDist parameterized by *mu* and *sigma* but offering English named properties for accessors. That gives lets us match other API that access mu and sigma, it matches the external resources on the topic, gives us clear english names in user code. The API extends nicely to LogNormal where the parameters and the summary statistic accessors are not the same.
https://bugs.python.org/issue36018
