On Tue, Oct 20, 2020 at 6:20 PM Chris Angelico <[email protected]> wrote:
> spam = eggs = cheese = None
> f"{spam:d} {eggs:d} {cheese:d}" = "123 456"
>
Wow! That sure looks like a strong anti-pattern.
If some variable was assigned somewhere very distant in the program flow, a
parser might succeed where it would otherwise fail! It's not technically
spooky action at a distance, but it's troublingly close.
In contrast a plain function has none of that problem behavior.
> > spam, eggs, cheese = sscanf("%d %d %d", "123 432", missing=None)
>
I wouldn't mind a version of this that was "inspired by" f-strings. But
even there, the requirements are subtly different. E.g.:
myvals = sscanf("{spam:d} {eggs:d} {cheese:d}", "123 432", missing=None)
I can see a good idea of `myvals` being a dictionary not a tuple. But
that's close to the color of the bikeshed.
Just to repeat, a "scanf-string" just cannot be the same thing as an
f-string. Here is a perfectly good f-string, similar to ones I use all the
time:
f"More than foo is {foo+1}"
There's just no way to make f-strings into an assignment target... what is
POSSIBLE is making "some subset of f-strings (yet to be precisely
specified)" patterns for a scan.
I hate the idea of putting that subset to the left of an equal sign. But
defining a subset as an argument for a function sounds great. Actually,
however, I think the scanf-string rules should be probably not strictly a
subset, but rather a "strongly overlapping set that is mostly a subset but
also has a few new things."
--
The dead increasingly dominate and strangle both the living and the
not-yet born. Vampiric capital and undead corporate persons abuse
the lives and control the thoughts of homo faber. Ideas, once born,
become abortifacients against new conceptions.
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