Using comments as arguments in python.
Using comments as arguments in python.
Python allows programmers to pass additional arguments to functions via comments. Now armed with this knowledge head out and spread it to all code bases.
Feel free to use the code I wrote in your projects.
Link to the source code: https://github.com/raldone01/python_lessons_py/blob/main/lesson_0_comments.ipynb
Image transcription:
from lib import add
# Go ahead and change the comments.
# See how python uses them as arguments.
result = add() # 1 2
print(result)
result = add() # 3 4
print(result)
result = add() # 3 4 5 20
print(result)
Output:
3
7
32
The best language is complete, succinct, orderly and clear. And never adds a single goddamn thing ever.
That is C++ levels of "why the fuck did they add that."
bro what we are devolving
Thanks, I hate it.
Why is this a thing
I hate this shit being routinely used in PHP. Symfony uses those functional comments for routing, essentially scanning every controller file as text on every visit, to gather the url patterns above functions. Laravel uses Reflection, which is functionally the same thing, to provide arguments to controller functions. Also, kind of related, the project I'm working now has few functions that use backtrace to return different results based on where they are called from. It is indeed very cursed and I'm ripping out any usages of them whenever I see one.
Comment Annotations were a nessecary thing as php did not support a native way to do it. However, since php 8, there is now native attributes.
This is heresy.
This is an affront to nature. Comments shouldn't even make it past the scanner.
we need a programming horror community for stuff like this
They chose violence.
I assume the people freaking out about how dumb python is didn't bother to read the code and have never coded in python in their life, because the behavior here is totally reasonable. Python doesn't parse comments normally, which is what you'd expect, but if you tell it to read the raw source code and then parse the raw source code for the comments specifically, of course it does.
You would never, ever accidentally do this.
...you'd also never, ever do it on purpose.
yeah frankly this post is borderline misinformation, they specifically import a library to read comments as arguments, it's like redefining keywords in C and complaining about C being dumb
I'm going to say it just is misinformation, if that's what "lib" is here.
IMO comments should never ever be parsed under any circumstances but I probably don't know enough to really speak on this
Can we just clarify that you mean that comments should never be parsed by the language engine. There are valid annotation systems, but the goal is alway to ensure that one passable can never impact the other.
Imagine if here a comment could create a syntax error! This is even worse for runtime scripting languages like python.
Sure, but let's just clarify that this is someone going out of their way to create this problem, using Python's ability to read it's own code.
Basically, you can load any text file, including a source code file, and do whatever you want with it.
So, a function can be written that finds out whatever's calling it, reads that file, parses the comments, and uses them as values. This can also be done with introspection, using the same mechanism that displays tracebacks.
No, your intuition is correct, this is extremely cursed.
The
addfunction in the example above probably traverses the call stack to see what line of the script is currently being executed by the interpreter, then reads in that line in the original script, parses the comment, and subs in the values in the function call.This functionality exists so when you get a traceback you can see what line of code triggered it in the error message
+1 to that!
One case where I find it useful, tho it operates in a more limited way, is code in block blocks within code comments in Rust, which are also printed out in the generated documentation. They essentially get ran as part of your unit tests. This is great for making sure that, eg, your examples left in code comments actually work, especially if they’re written in a way that functions like a unit test.
Ignoring lint issues comes to mind as an at least somewhat reasonable use case.
Some languages use the comments to generate documentation. Something like
// function to add two numbers func Add(num1 int, num2 int)
I fucking hate this, thanks OP
How do I delete this part of the python documentation?
That's disgusting
This is some javascript level shit
It's actually kind of nice to see this as a JS developer.
Not like, "Oh wow this is neat!"
But like, "Finally the golden child, Python, also has some fucked up shit"
Thank you, I hate it
checks the community to make sure I'm in programmer humor
Yeah that checks out
You know that this is acutally working right??? 😊
Yup, just one of those posts that could of course work in either
Implementation of the
add()function is here: https://github.com/raldone01/python_lessons_py/blob/main/lib.pyYup, the function actually goes and finds the code that calls it and parses the comment.
Disgusting.
This does not actually work, right? Right?
they have to import a separate library to do this, it's not a part of standard python, and this post is basically just misinformation
The
add()function (that is available in the source code) basically uses some built in debugging tools to find out where in the code the function is called, and then parses the comment from the file and uses it for adding stuff.I’ve never tried (becuse why would you…) but something similar can probably be built in any interpreted language
It’s not something Python does by design
Anakin:
Anakin:
~~It does work~~ I know it at least partially works
class add: count = 0 def __init__(self): add.count += 1 self.value = add.count def __str__(self): if self.value == 1: return "3" elif self.value == 2: return "7" else: return "32" result = add() # 1 2 print(result) result = add() # 3 4 print(result) result = add() # 3 4 5 20 print(result)
Every day further from god's light etc...
As if I needed more reasons to start away from python
You can so stupid shit in any language. I admit Python doesn't exactly make it difficult. A bit like JS, but different.
Do you stay away from C++ too? You can do this there too
https://en.cppreference.com/w/cpp/utility/source_location/line
I feel sick
That's quite cool. But I'm not sure what's the use case for it.
To make bugs less traceable, I guess.
What? There is no
libmodule.$ python3.13 -c 'import lib' Traceback (most recent call last): File "<string>", line 1, in <module> import lib ModuleNotFoundError: No module named 'lib' $OP wrote this add() function and has provided their own lib module in the source code.
Oh, so it’s not Python that’s cursed.
One of Python’s design philosophies is—or at least was—“we are all consenting adults here.” If you really want to turn Python into Brainfuck, the interpreter isn’t going to stop you.
Why, just why
because OP wanted upvotes, this isn't actually part of python in any way, it's using a custom library to do it.
Makes sence if u think about it. We use comments as docstrings that the interpreter has an understanding of. Python lets u fuck with its internals (at least in an immutable manner) so why not fuck with comments.
TMI 😢
