[Python-Dev] (no subject)

[Victor Stinner]

Hi,

2015-02-09 22:06 GMT+01:00 Neil Girdhar <mistersheik at gmail.com>:
> The updated PEP 448 (https://www.python.org/dev/peps/pep-0448/) is
> implemented now based on some early work by Thomas Wouters (in 2008) and
> Florian Hahn (2013) and recently completed by Joshua Landau and me.

I don't like this PEP. IMO it makes the Python syntax more complex and
more difficult to read.

Extract of the PEP:
> Current usage of the * iterable unpacking operator features unnecessary restrictions that can harm readability.

Yes, the current syntax is more verbose, but it's simpler to
understand and simpler to debug.

--

Example:

>>> ranges = [range(i) for i in range(5)]
>>> [*item for item in ranges]
[0, 0, 1, 0, 1, 2, 0, 1, 2, 3]

I don't understand this code.

It looks like you forgot something before *item, I would expect 2*item
for example.

If it's really to unpack something, I still don't understand the
syntax. Does "*" apply to item or to the whole "item for item in
ranges"? It's not clear to me. If it applies to the whole generator,
the syntax is really strange and I would expect parenthesis: [*(item
for item in ranges)].

--

> function(**kw_arguments, **more_arguments)

If the key "key1" is in both dictionaries, more_arguments wins, right?


I never suffered of the lack of the PEP 448. But I remember that a
friend learning Python asked me that * and ** are limited to
functions. I had no answer. The answer is maybe to keep the language
simple? :-)

I should maybe read the PEP one more time and think about it.

Victor