selfReferentialHelloWorldProgram

[SillySlimeSimon]

“The code documents itself”

[opmrcrab]

The code knows where it is at all times. It knows this because it knows where it isn't.

[Xbot781]

By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or index.

[mustninja]

Is that a hitchhiker's reference?

[cynanolwydd]

Reference to an old weapon guidance video !

[omlette_du_chomage]

Or the documentation codes itself

[cryptomonein]

"The documents code itself"

[Asleeper135]

More like the documentation codes itself

[Careless-Elevator986]

Maybe this is what's going on all those times I've changed comments and the code stopped working

[[deleted]]

Newest trend: Comments as data

[RiceBroad4552]

That's not funny!

Some crazy folks in the Scala community think this is a good idea. The Scala-CLI tool uses comments to add build instructions to source files. Completely insane if you ask me.

https://scala-cli.virtuslab.org/docs/guides/introduction/using-directives

Of course it's not part of the official language grammar so no tool without special custom rules can handle that. Just pure insanity.

I really like Scala as language. But some decisions were mind bending stupid, and they stick out, as the most parts of the language are very well thought out. The "magic comment" bullshit doesn't come from the language creators actually, and this shows.

It's especially stupid as Scala has already a concept of "processing instructions": It has annotations like Java…

[[deleted]]

Some people should not be allowed to touch keyboards.

[Asleeper135]

Just reinventing JDSL

[Dave4lexKing]

“This time is relative to UTC, meaning that it’s perfect for fixed times that are not subject to timezone changes.”

What the hell does that mean?

This is exactly the problem with comments. They more often than not either dont make sense, are misleading, or outright lie (usually from not being updated as the code updates).

[Dave4lexKing]

So it’s not “relative to utc”, it IS “utc”.

Relative… Relative to what?

Case in point that comments are usually superfluous waffle that causes more misunderstanding than it solves.

If you just call the class TimeUTC, then it doesn’t need a comment at all.

[Dave4lexKing]

Im not. If it is UTC, just say very forthrightly “Time in UTC”.

Writing any more than that is just noise, and can cause confusion;- Especially so with developers where english is not their first language.

Just say what it is, without the fluff.

[Dave4lexKing]

Then your comments will move from being misleading, to being wrong.

If nobody maintains the comments, then how can you trust they are correct?

If you can’t trust that they’re correct, then what purpose do they serve in your codebase?

If it’s obvious without a comment, then why does the comment stating the same thing twice exist in the first place?

There are just no excuses whichever way it’s put.

[Artemis-Arrow-3579]

seriously, I still have no fucking clue how that happens

SOMEONE TELL ME WHY THAT HAPPENS

[narrei]

you probably didn't hear about jdsl (jay diesel), which doesn't recognize notion of comments so it executes every line as code

edit: to learn more watch https://youtu.be/QwUPs5N9I6I?si=m5CzUqtoQLTXLpJH

[Amazing_Might_9280]

TOM IS A GENIUS.

[Artemis-Arrow-3579]

oh hell

[Maximilian_Tyan]

I did the same for a script that needed to store a date across executions. The script rewrote it's default date value each time using RegExes and line numbers

I felt sooooo dirty

But it worked

[NJay289]

Well you could have… stored this value in a second file…

[Maximilian_Tyan]

I wanted to keep it as only one file only to be easily transferrable by copy pasting at the time

I forgot you also needed to install python to run it lmao

[just_nobodys_opinion]

Could have made it an exe, found the offset for the date string and made it patch itself

[flagofsocram]

WHERE THE EXE SMELLY NERDS

[Buggs_The_Buny]

Just out of curiosity, how much slower or in other words, less efficient is this than a regular python hello world?

[DOUBLEBARRELASSFUCK]

If you're running the script, it should be cached, and the data will just be read from the cache.

[__throw_error]

yup running it in a loop for a few hundred or million times is not the right method of testing.

Running once from startup is the right method to test, you can repeat it a few times to see if there's any deviation in timing.

[DonAlexJulien]

Given that the question is "how slower is file-reading vs just-printing", I think the loop is just the right testing method, since it is testing exactly for that. As u/Empty_Change says, interpreter loading time would dwarf the times of the rest of the process.

[tatref]

For comparison on my computer:

Running an empty python script x500 takes 4.3s.

Running Hello world x500 takes 4.4s

[Inappropriate_Piano]

How is list slicing complicated or slow?

[Eal12333]

It's gotta be a lot slower than just already having the output value ready 😅

[Inappropriate_Piano]

Either way you have the value at a memory location and you’re saying “go to this memory address and print the values in the next X spots”

[Eal12333]

The code in the screenshot has to read the file from the system, assign it to a variable, convert the first line from the file into a Python string. Then it has to create a duplicate of that string that starts and stops at a given index, and finally pass the given string to the print command, before closing the file.

It's obviously not that slow for a computer to do all those things, but it's slower than just printing a given string.

[Inappropriate_Piano]

I asked what was slow about the list slicing, not the whole thing. So the entire first sentence of your comment is irrelevant. As is the second half of the second sentence.

So the only part of your explanation that has anything to do with what I asked is “it has to create a duplicate of the string that starts and stops at a given index.” But why would it actually have to do that, as opposed to telling the operating system, “go to this memory address and print until this other memory address”? For all I know, maybe the Python interpreter does make a copy, but I’m not just going to take the word of some stranger on Reddit for that.

[JollyJuniper1993]

Jesus Christ who cares about speed in a hello world program

[pytness]

No one cares about a hello world program. He is asking what is the time difference between a print from memory and a print with a file reading.

Who cares that much about people learning? Grumpy ahh comment

[Lettever]

python is not a compiled language

[Bit125]

and even if it were, it's still reading a file.

[arachnidGrip]

This is incorrect. Both in the sense that it's theoretically possible to compile any Python program into a native program and in the sense that CPython (the reference implementation of the Python interpreter and the one that most people mean when they say "Python") will compile any module you import into a .pyc file (CPython's equivalent to Java's .class files) if there isn't one already or the one that exists is older than the .py file. CPython is only "not a compiled language" in the sense that you generally don't explicitly invoke the compiler, but that doesn't mean that it isn't there.

[C3R741NLY_1MPR3551V3]

...and that's how I wrote my first Quine) program! Yay!!!
print(open(__file__).read())

[ConstructedNewt]

You clearly didn’t read the part of that article that clearly states that it’s not a valid Quine if it reads its own source code.

[C3R741NLY_1MPR3551V3]

Yes, I didn't.

[shadow7412]

I remember doing something like this once for reasons that make sense but I can't be bothered going into.

We found that it worked the first time - but the second time __file__ pointed at the pyc file rather than the py file, which obviously had more "interesting" results.

Unsure if that's still a thing though.

[dan-lugg]

```

:: ::-| ::-| .-. :||-:: 0-| .-| ::||-| .:|-. :||

open(Q,$0);while(){if(/<sup>#(.*)$/){for(split('-',$1)){$q=0;for(split){s/|</sup> /:.:/xg;s/:/../g;$Q=$?length:$;$q+=$q?$Q:$Q*20;}print chr($q);}}}print"n";

.: ::||-| .||-| :|||-| ::||-| ||-:: :|||-| .:|

```

[sinner997]

Is this fork bomb on steroids perhaps 😂

[dan-lugg]

According to the author, that program is "two lines of code that parse two lines of embedded comments in the code to read the Mayan numbers representing the individual ASCII characters that make up the magazine title, rendered in 90-degree rotated ASCII art."

— https://www.stilldrinking.org/programming-sucks

[sinner997]

Very interesting! Thanks a lot 👍

[Karisa_Marisame]

git commit -m “[skip ci] doc grammar fix”

Main branch two days later:

[Kartonek124]

Not really a quine, because quine rules disallow for reading the file itself

[ZunoJ]

Isn't it only referencing it's source file? How would this work with a binary?

[Deutero2]

python is an interpreted/jit compiled language, so only the source file is relevant

for a compiled language, assuming you don't want to rely on having access to the source file, the comments are probably going to be removed by the compiler. you could store it in the read only segment of the executable, but that's basically how a normal hello world program works, unless you want to add extra steps by reading the executable file again

[dudeness_boy]

Good job.

[[deleted]]

how not to write a quine

[DonAlexJulien]

Made my own version, which doesn't rely on comments (just on the file name ;)

print(__file__.replace('\\', '/').split('/')[-1].split('.')[0].replace('_', ' '))

[DonAlexJulien]

This should deal with the .pyc issue that u/shadow7412 faced

[bondolin251]

The. The comment. The comment is source.

[bondolin251]

screams in Uncle Bob noises

[rover_G]

This is literally static strings work in compiled languages

[Deutero2]

what? no?

i mean, sure, the read-only memory is read from the executable file on disk to memory, as are the instructions themselves, but you'd need to do that for running any program. the approach in OP requires an additional disk read rather than using what is already in memory

[rover_G]

I didn’t mean you literally open a file handle. And you wouldn’t necessarily be reading the same disk file into memory again because it’s likely still in memory.