For review: PEP 308 - If-then-else expression
ark at research.att.com
Sat Feb 8 18:07:05 CET 2003
holger> a) it reads ugly especially in non-assignment statements
holger> "Beautiful is better than ugly."
But what is beautiful and what is ugly is still subjective.
I think that
if x > 0.0:
y = math.sqrt(x)
y = 0.0
is ugly compared to
y = math.sqrt(x) if x > 0.0 else 0.0
holger> b) it reuses a keyword which formerly was a clean indicator
holger> of a statement
>> Subjective, especially when you realize that "if" is already thus
>> reused in list comprehensions.
holger> Still "Readability counts."
And readability is often subjective. Anyway, it would still be true that
a statement is an if statement whenever its first token is "if".
holger> d) there are often better ways than doing the C-ish
holger> 'x ? y : z'
>> Agreed, but that's not an argument against PEP 308 unless you
>> change "often" to "always".
holger> "Special cases aren't special enough to break the rules."
Although practicality beats purity.
holger> e) adds to the stuff you have to learn if you read others code
>> Agreed, but the importance of that is subjective.
holger> Sure, why not use perl, then?
A sufficient reason for me is the lack of orthogonality in Perl's
holger> f) is not an important enough use case to warrant new syntax
holger> Now I wonder what you might deem not to be subjective.
holger> I guess that the "design prinicples" of python in
holger> are mostly subjective categories, too, then.
holger> That's ok but i *like* them :-)
What I deem not subjective is statements like:
Here's an example of how I'd like to use this feature.
Without it, I have to do it this way. Which form do you prefer?
In another (long) message in this thread, I did just that for a
2800-line C program that I wrote 20 years ago. What those examples
show is how one programmer used ?: in practice. Readers can then
judge for themselves whether the use of ?: gained or lost on balance.
More information about the Python-list