On 11/12/2019 8:29 AM, Chris Angelico wrote:
The OP said that the equals sign in the *first* line was flagged as
invalid syntax. Implication being that the error is being reported on
the line "i = 4", not on the print at the end. And in fact, I can
confirm this. Run | Check Module reports an error where i is assigned
to. Here's how it looks in command-line Python:
$ python3.7 demo.py
File "<fstring>", line 1
(i=)
^
SyntaxError: invalid syntax
Newer Pythons are happy with this example, but if you replace the
error with something else - say, f'{i+}' - then the same phenomenon
occurs. Command-line Python reports the error on line 1 of
"<fstring>", and Idle misinterprets that as line 1 of the original
file.
This looks like an error reporting flaw in f-string handling.
Can you open a bug issue (if not one already) and nosy me?
This is awful for any IDE that processes error messages.
Replacing {} with () is a secondary bug. The actual code
{i=}
would be clearer, and make it easier for an IDE to search for the real line.
IMO it
should just count the entire f-string as being at the line and file
that the f-string starts; when working with triple-quoted f-strings, I
was only able to get line numbers above 1 by having a multi-line
braced expression, and that's not something we should be encouraging.
This is also consistent with the way other errors in triple-quoted
strings are handled:
print('''hello
world
\N{ASDF}
asdf
qwer''')
File "/home/rosuav/tmp/demo.py", line 1
print('''hello
^
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes
in position 12-19: unknown Unicode character name
If it can find the position of the specific braced expression within
the string, great! But at very least, it should report the location of
the string in its original file.
--
Terry Jan Reedy
--
https://mail.python.org/mailman/listinfo/python-list
