On 12/01/24 10:33, Left Right via Python-list wrote:
By the way, in an attempt to golf this problem, I discovered this,
which seems like a parser problem:
This is what Python tells me about its grammar:
with_stmt:
| 'with' '(' ','.with_item+ ','? ')' ':' block
| 'with' ','.with_item+ ':' [TYPE_COMMENT] block
| ASYNC 'with' '(' ','.with_item+ ','? ')' ':' block
| ASYNC 'with' ','.with_item+ ':' [TYPE_COMMENT] block
with_item:
| expression 'as' star_target &(',' | ')' | ':')
| expression
From which I figured why not something like this:
with (open('example.txt', 'r'), open('emails.txt', 'w'),
open('salutations.txt', 'w')) as e, m, s:
for line in e:
if line.strip():
(m if '@' in line else s).write(line)
Which, surprise, parsers! But it seems like it's parse is wrong,
because running this I get:
❯ python ./split_emails.py
Traceback (most recent call last):
File "/home/?/doodles/python/./split_emails.py", line 1, in <module>
with (open('example.txt', 'r'), open('emails.txt', 'w'),
open('salutations.txt', 'w')) as e, m, s:
TypeError: 'tuple' object does not support the context manager protocol
It seems to me it shouldn't have been parsed as a tuple. The
parenthesis should've been interpreted just as a decoration.
NB. I'm using 3.11.6.
A series of comma-separated items will be parsed as a tuple (some people
think it is bounding-parentheses which define).
In this case, the issue is 'connecting' the context-manager "expression"
with its (as) "target". These should be more-closely paired:-
with ( open( 'example.txt', 'r', ) as e,
open( 'emails.txt', 'w', ) as m,
open( 'salutations.txt', 'w', ) as s
):
(NB code not executed here)
A data-architecture of having related-data in separated serial-files is
NOT recommendable!
--
Regards,
=dn
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