[Python-Dev] (name := expression) doesn't fit the narrative of PEP 20 (original) (raw)

Terry Reedy tjreedy at udel.edu
Thu Apr 26 03:31:13 EDT 2018


On 4/25/2018 8:20 PM, Chris Angelico wrote:

On Thu, Apr 26, 2018 at 10:11 AM, Yury Selivanov <yselivanov.ml at gmail.com> wrote:

Just yesterday this snippet was used on python-dev to show how great the new syntax is:

myfunc(arg, buffer=(buf := [None]*getsize()), size=len(buf))

What strikes me as awful about this example is that len(buf) is get_size(), so the wrong value is being named and saved. 'size=len(buf)' is, in a sense, backwards.

buflen = get_size() my_func(arg, buffer = [None]*buflen, size=buflen)

Is standard, clear Python code. I do not see that my_func(arg, buffer=[None]*(buflen:=get_size()), size=buflen) is an improvement.

-- Terry Jan Reedy



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