People ITT hating on null coalescing operators need to touch grass. Null coalescing and null conditional (string?.Trim()) are immensely useful and quite readable. One only has to be remotely conscious of edge cases where they can impair readability, which is true of every syntax feature
Languages with null in them at all anymore just irk me. It’s 2023. Why are we still giving ourselves footguns.
Because you can turn null into an Option monad with a small amount of syntax sugar and static analysis
Because I use a language that was invented more than 1 year ago
You use the language? Weren’t they just for bragging rights and blog posts?
Oh yeah I forgot, first you have to make a blog post, then a devlog, then review the top 10 best features of JS es6 (9 years after it was released…). Then
shitpost on social medianetwork for the other half of the week, and boom! You’re officially a Master Programmer!
a.unwrap_or(b)
🦀
There’s a nice list of this feature by language on the Wikipedia page for anyone interested: https://en.wikipedia.org/wiki/Null_coalescing_operator#Examples_by_languages
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For the love of god, please do not use single-line alternatives to braced scopes. It’s only tolerable in lambdas like
Array.map( v => v**2 ). It’s not for an implicit scope. It’s for evaluating a return value.But holy shit is it nice to have
?.in Javascript. It’s such an anything-goes language until you look at it funny and it just shits the bed and silently dies. Hate hate haaate having to check if things exist, when so many other details fail politely and impact nothing. At least now it’s one extra character instead of try-catch rigmarole.I’m fine with non-braced blocks, but they must always be on the same line as the parent statement (e.g.
if (a != null) return a) to visually distinguish them. (inb4 argument about long conditions: they’d usually be spread out over several lines, and the statement would go on the closing parenthese (which is on a line by itself when split over multiple lines))
I work with python so here’s python
return a or bI work with lisp so here’s lisp
(or a b)
Please don’t use #2. It is how you get the goto fail bug
I hate this so much. Literally stopped using Perl and switched to PHP to get away from the “Look, ma! I can condense 6 comprehensible lines to one complete gibberish line that still works!” crowd.
I’m not saying I won’t use shorthand if/else format on very rare occasions where you have to do a bunch of different if else’s within your HTML for some reason, but in general, I try to avoid it.
Nullish coalescing makes a lot of stuff much easier to read and write.
My coworker flips his shit every time I include a ternary operator in a PR. He also insists on refactoring any block of code longer than two lines into its own function, even when it’s only used once.
He is not well liked.
Python, checking in …
return (a or b)Parentheses aren’t necessary, I just prefer them for readability.
See python documentation on boolean operators for reference. Short story is
a or bis an expression that evaluates toaifais “truthy” elseb. “Falsy” is empty strings/containers,0andNone.(or a b)i never thought of lisp as concise before
Except there’s literally no change in performance as a normal compiler will treat those the same. It just looks nice and trim down the time an experienced dev reads and understands the code by around 200ms.
And no one on his team ever understood his code.
Sometimes being declarative is better than being “smart”
I’m confused on how this is difficult to understand. Put aside the fact that it’s just a regular operator that… I mean virtually everyone should know, how hard is it to google “what does ?? mean in [language]” which has the added benefit of learning a new operator that can clean up your code?
If condition then this else that vs this ?? that
Which option do you think requires less time for a person to identify and understand?
Sure if it’s just your own code do whatever comes natural to you but there’s a reason we don’t use these kind of logical operators in day to day speech is my point.
Ive been a backend dev for 2 years now and I’ve never come across the ?? operator and every time I come across a ternary operator I have to Google in what order comes what.
Not saying it doesn’t make the code more concise and less “noisy” but sometimes a simple if else statement just makes the code easier to mantain
It’s easier to mess up
return a != null ? a : bthan it isreturn a ?? b, and operators work from left to right.
Well yeah but imagine you had to do that on most lines of the code? It would become very distracting imho. If you are in a team with people that have a lot experience and or will learn more anyway this is fine. But if you are in a team with not very good programmers which “will never learn” because they have other stuff to do, you should be careful when using code like this. Though I would prefer in the former of course.
Honestly, and I mean this sincerely, if you’re on a team where the nullable coalesce is going to be confusing after the first handful of times encountered… look for a new job. It doesn’t bode well for their ability to do their jobs.
This is like the guy at Walmart who needs hand holding each time they clean a machine, it’s a problem waiting to happen.
Imo it’s context dependent. Obligatory “I’m only a college student/intern” out of the way.
Whenever I’m working with a project with multiple languages (e.g. split frontend+backend, different connected services, etc.) operators like that can get blurry when they aren’t consistent between lancuages. Especially when one of those languages doesn’t have runtime type enforcement or has weird boolean behavior (looking at you JS/TS) which can lead to unintended behavior
If everyone on the project is only working with that language, then your point is probably pretty close to the mark.
Yes! Please be declaritive for the next people in line!
Ruby:
a || b(no
returnas last line is returned implicitly, no semicolon)EDIT: As pointed out in the comments, this is not strictly equivalent, as it will return
bifaisfalseas well as if it’snil(these are the only two falsy values in Ruby).Python:
return a or bi like it because it reads like a sentence so it somewhat makes sense
and you can make it more comprehensive if you want to:
return a if a is not None else bThis diverges from the OP code snippets if a has the value
False.For newer python people, they see return a or b and typically think it returns a boolean if either is True. Nope. Returns a if a is truthy and then checks if b is truthy. If neither are truthy, it returns b.
Returns a if a is truthy and then checks if b is truthy. If neither are truthy, it returns b.
Not quite. If
ais not truthy, then the expressiona or bwill always returnb.So, there is never any reason to check the truthiness of
b.you can paste this in your repl to confirm it does not.
class C: def __repr__(self): return [k for k, v in globals().items() if v is self][0] def __bool__(self): print(f"{self}.__bool__() was called") return False a, b = C(), C() print(f"result: {a or b}")output
a.__bool__() was called result: b
