ftfy
bool IsEven(int number) { return !IsOdd(number); } bool IsOdd(int number) { return !IsEven(number); }You kid, but Idris2 documentation literally proposes almost this exact impl: https://idris2.readthedocs.io/en/latest/tutorial/typesfuns.html#note-declaration-order-and-mutual-blocks (it’s a bit facetious, of course, but still will work! the actual impl in the language is a lot more boring: https://github.com/idris-lang/Idris2/blob/main/libs/base/Data/Integral.idr)
I hadn’t seen Idris2. Thank you for providing me with a new rabbit hole!
I’m glad to tell more people about it. It’s really quite amazing (I could write a somewhat complex algorithm and prove some properties about it in a couple afternoons, despite limited formal verification experience) and I’m sure that in 20 odd years the ideas behind it will make it into mainstream languages, just as with ML/Haskell.
YanDev: “Thank God I’m no longer the most hated indie dev!”
YanDev is a literal pedophile. It’s honestly mind boggling people care more about a guy who won’t sign a petition on preserving video games than pedophiles and bigots. I don’t get the hate.
it’s not that he “wont sign it”. lmao. its that he comoketely unprovoked started a hate campaign against it, literally on the spot hearing about it on stream, directed his viewers not to engage with the petition and started making up a bunch of reasons while talking in that confident-but-clulesss voice about how its destructive and awful and short sighted, making up a bunch of atuff about it that was immediately disproven, just spewing all this vitriol for no reason. Not engaging with it is one thing but actively fighting against a wonderul consumer rights campaign like this, not to mention how important iy is to gaming history to be able to preserve games, is so anti-gamer i dont understand how he ever got a following. Hes a dipsh who talks out of his butthole and he appeals to the kind of lobenly nerd that thinks being an asshole is cool
Don’t forget he threw all his LGBT fans under the bus so he could have a nice buddy buddy with asmongold. Resulting in his community being invested with asmongold’s hateful degen followers, calling his LGBT fans horrific slurs.
But hey! Atleast he was able to defend the game Ashes of Creation or whatever its called against asmonshit…
Then when fans called him out, he went “Just cancel me, i guess…” fucking manchild…
Random website but just for a article that gives a summary of what happened: https://www.sportskeeda.com/us/streamers/news-i-again-pirate-software-defends-collaboration-asmongold-amid-backlash-fans
He uses multiple times insults that you’d hear from a teen. He’s not funny, not clever, has limited communication skills ans generally speaking unlikable. He’s not a role model, stay away from these.
Pirate Software is also a big liar, and a bad dev, who couldn’t finish his game in 8 years.
This is why this code is good. Opens MS paint. When I worked at Blizzard-
That code is so wrong. We’re talking about Jason “Thor” Hall here—that function should be returning 1 and 0, not booleans.
If you don't get the joke...
In the source code for his GameMaker game, he never uses
trueorfalse. It’s always comparing a number equal to 1.Frankly, it’s what I did, too, after coming out of Uni-level C.
My code was goddamn unreadable.
It’s the same for a lot of people. Beginners are still learning good practices for maintainable code, and they’re expected to get better over time.
The reason people are ragging on PirateSoftware/Jason/Thor isn’t because he’s bad at writing code. It’s because he’s bad at writing code, proclaiming to be an experienced game development veteran, and doubling down and making excuses whenever people point out where his code could be better.
Nobody would have cared if he admitted that he has some areas for improvement, but he seemingly has to flaunt his overstated qualifications and act like the be-all, end-all, know-it-all of video game development. I’m more invested in watching the drama unfold than I should be, but it’s hard not to appreciate the schadenfreude from watching arrogant influencers destroy their reputation.
He’s totally one of those people that’s sort of attractive and has an authoritative voice so s lot of people have probably folded to him in arguments through his life. I don’t like making generalizations like that about people but this isn’t the first time he’s acted like this. The one that really took the cake was the whole hardcore WoW raid debacle.
The TL;DR is, as well as not trying to really spend time on the parts that don’t matter, he did some things that may or may not have been the right thing to do in the situation depending on your perspective. But whenever any of his guild mates or other viewers would criticize him he’d be so adamant that no, he didn’t do anything wrong, he did exactly what he was supposed to do, etc. People would even explicitly tell him “hey, what’s pissing us off now isn’t that you did it, it’s that you’re so adamant you couldn’t have possibly made a mistake, you’re not willing to see our perspective. You’re not willing to admit that maybe you could’ve been wrong. You’re not willing to apologize.” And still, his reaction to this was to triple down and just insist he didn’t do anything wrong.
Like I literally even saw a clip of him talking to someone and he said “a lot of people think I’m being condescending when really I’m just providing context.” And the guy talking to him points out “yeah, it’s a problem that you think anyone disagreeing with you doesn’t understand the situation, it’s like you think they’re stupid.” It’s like it short circuited his brain. It’s like he’d never considered it.
So yeah, I have a pretty low opinion of him. But I also recognize that maybe all these clips are taken out of context, who knows. It’s not like my opinion really matters. I don’t work with him or know him. I don’t care about streamers. I don’t really watch them.
I am working with C in embedded designs and I still use 1 or 0 for a bool certain situations, mostly lines level.
For whatever pea-brained reason, it feels yucky to me to set a gpio to true/false instead of a 1/0.
I’m partial to a recursive solution. Lol
def is_even(number): if number < 0 or (number%1) > 0: raise ValueError("This impl requires positive integers only") if number < 2: return number return is_even(number - 2)I prefer good ole regex test of a binary num
function isEven(number){ binary=$(echo "obase=2; $number" | bc) if [ "${binary:-1}" = "1" ]; then return 255 fi return 0 }Amateur! I can read and understand that almost right away. Now I present a better solution:
even() ((($1+1)&1))(I mean, it’s funny cause it’s unreadable, but I suspect this is also one of the most efficient bash implementations possible)(Actually the obvious one is a slight bit faster. But this impl for
oddis the fastest one as far as I can tellodd() (($1&1)))woah your bash is legit good. I thought numeric pretexts needed
(( blah )), but you’re ommiting the $ like an absolute madman. How is this wizardy possibleSee:
man bash, “Compound Commands” and “Shell Function Definitions”Oh I see it, but for some reason I was taught to always use
(( arith ))instead of(( arith ))and I guess I’m just wondering what the difference isThe difference is that
((is a “compound command”, similar to[[(evaluate conditional expression), while(( ))is “aritmetic expansion”. They behave in almost exactly the same way but are used in different contexts - the former uses “exit codes” while the latter returns a string, so the former would be used where you would expect a command, while the latter would be used where you expect an expression. A function definition expects a compound command, so that’s what we use. If we used(( ))directly, it wouldn’t parse:$ even() $((($1+1)&1)) bash: syntax error near unexpected token `$((($1+1)&1))'We would have to do something like
even() { return $(($1&1)); }(notice how this is inverted from the
((case -((actually inverts 0 -> exit code 1 and any other result to exit code 0, so that it matches bash semantics of exit code 0 being “true” and any other exit code being “false” when used in a conditional)But this is a bit easier to understand and as such wouldn’t cut it, as any seasoned bash expert will tell you. Can’t be irreplaceable if anyone on your team can read your code, right?
I can’t think of many use-cases for
((. I guess if you wanted to do some arithmetic in a conditional?if (( $1&1 )); then echo "odd!"; else echo "even!"; fiBut this is pretty contrived. This is probably the reason you’ve never heard of it.
This
((vs.(( ))thing is similar to how there is(compound command (run in a subshell), and$( )(command substitution). You can actually use the former to define a function too (as it’s a compound command):real_exit() { exit 1; } fake_exit() ( exit 1 )Calling
real_exitwill exit from the shell, while callingfake_exitwill do nothing as theexit 1command is executed in a separate subshell. Notice how you can also do the same in a command substition (because it runs in a subshell too):echo $(echo foo; exit 1)Will run successfully and output
foo.((being paired with$((, and(with$(, is mostly just a syntactic rhyme rather than anything consistent. E.g.{and${do very different things, and$[[just doesn’t exist.Bash is awful. It’s funny but also sad that we’re stuck with it.
amazing, thanks!
I’m waiting for a code golf style solution now.
I don’t think there’s much to codegolf. The “obvious” solution (
even() (($1%2))) is both shorter and faster. Don’t think it can be optimized much more.
def even(n: int) -> bool: code = "" for i in range(0, n+1, 2): code += f"if {n} == {i}:\n out = True\n" j = i+1 code += f"if {n} == {j}:\n out = False\n" local_vars = {} exec(code, {}, local_vars) return local_vars["out"]scalable version
Plot twist: they used a script to generate that code.
You don’t get it, it runs on a smart fridge so there’s no reason to change it
- a smart fridge’s monitor
def is_even(num): if num == 1: return False if num == 2: return True raise ValueError(f'Value of {num} out of range. Literally impossible to tell if it is even.')This is YandereDev levels of bad.
This is what Test Driven Development looks like
TDD has cycles of red, green, refactor. This has neither been refactored nor tested. You can tell by the duplication and the fact that it can’t pass all test cases.
If this looks like TDD to you, I’m sorry that is your experience. Good results with TDD are not guaranteed, you still have to be a strong developer and think through the solution.
As the existing reply stated, there are only ever finitely many tests.
My issue with TDD is that it pretends to drive the final implementation with tests, but what is really driving the implementation is the monkey at the keyboard thinking, “testing for evenness should be done with the modulo operation,” not exhaustive tests.
The monkey at the keyboard thinking is what software development is. When faced with a failing test, you make it pass as simply as possible, and then you summon all your computer science / programming experience to refactor the code into something more elegant and maintainable.
In this case that is using math to check if the input is divisible by two without a remainder. If you don’t know how that works, you’re going to have a bad time, like the picture in this post.
TDD doesn’t promise to drive the final implementation at the unit level, but it does document how the class under test behaves and how to use it.
When faced with a failing test, you make it pass as simply as possible, and then you summon all your computer science / programming experience to refactor the code into something more elegant and maintainable.
Why bother making it pass “as simply as possible” instead of summoning all that experience to write something that don’t know is stupid?
TDD doesn’t promise to drive the final implementation at the unit level
What exactly does it drive, then? Apart from writing more test code than application code, with attendant burdens when refactoring or making other changes.
The rhythm of TDD is to first write a failing test. That starts driving the design of your production code. To do that you need to invoke a function/method with arguments that responds with an expected answer.
At that point you’ve started naming things, designing the interface of the unit being tested, and you’ve provided at least one example.
Let’s say you need a method like
isEven(int number): Boolean. I’d start with asserting 2 is even in my first test case.To pass that, I can jump to
number % 2 == 0. Or, I can just returntrue. Either way gets me to a passing test, but I prefer the latter because it enables me to write another failing test.Now I am forced to write a test for odd input, so I assert 3 is not even. This test fails, because it currently just returns
true. Now I must implement a solution that handles even and odd inputs correctly; I know modulus is the answer, so I use it now. Now both tests pass.Then I think about other interesting cases: 0, negative ints, integer max/min, etc. I write tests for each of them, the modulus operator holds up. Great. Any refactoring to do? Nope. It’s a one-liner.
The whole process for this function would only add a few minutes of development, since the implementation is trivial. The test runtime should take milliseconds or less, and now there is documentation for the next developer that comes along. They can see what I considered (and what I didn’t), and how to use it.
Tests should make changing your system easier and safer, if they don’t it is typically a sign things are being tested at the wrong level. That’s outside the scope of this lemmy interaction.
Either way gets me to a passing test, but I prefer the latter because it enables me to write another failing test.
But you could just write that failing test up front. TDD encourages you to pretend to know less than you do (you know that testing evenness requires more than one test, and you know the implementation requires more than some if-statements), but no-one has ever made a convincing argument to me that you get anything out of this pretence.
Tests should make changing your system easier and safer, if they don’t it is typically a sign things are being tested at the wrong level
TDD is about writing (a lot of) unit tests, which are at a low-level. Because they are a low-level design-tool, they test the low-level design. Any non-trivial change affects the low-level design of a component, because changes tend to affect code at a certain level and most of those below it to some degree.
Unittest in Python, enjoy! If you pass it with a function like the one in OPs picture, you have earned it.
import unittest import random class TestOddEven(unittest.TestCase): def test_is_odd(self): for _ in range(100): num = random.randint(-2**63, 2**63 - 1) odd_num = num | 1 even_num = num >> 1 << 1 self.assertTrue(is_odd(odd_num)) self.assertFalse(is_odd(even_num)) def test_is_even(self): for _ in range(100): num = random.randint(-2**63, 2**63 - 1) odd_num = num | 1 even_num = num >> 1 << 1 self.assertTrue(is_even(even_num)) self.assertFalse(is_even(odd_num)) if __name__ == '__main__': unittest.main()I don’t want unseeded randomness in my tests, ever.
Seed the tests, and making these pass would be trivial.
The right tool for the right job ¯\(ツ)/¯
The right tool here is tests at a level higher than machine code instructions that have been in CPUs since the 70s. Maybe TDD practice is not to test at this level, but every example of TDD sure tends to be something similar!
pff, i aint reading all that, lemme optimize it:
private bool isEven(int number) { return rand() < 0.5; }I’ll join in
const isEven = (n) => !["1","3","5","7","9"] .includes(Math.round(n).toString().slice(-1))I’ve actually written exactly that before, when I needed to check the lowest bit in an SQL dialect with no bitwise operators. It was disgusting and awesome.
pro hacker tip: you can optimize this by using “num” for the variable name instead of “number”
This code would run a lot faster as a hash table look up.
I agree. Just need a table of even numbers. Oh and a table of odd numbers, of course, else you cant return the false… duh.
In a Juliana tree, or a dictionary tree if you want. For speed.
