Is it really tempting for people? They’ve given me too many headaches when I’ve had to reformat or add functionality to files.
Unless it’s a simple single use script that fit on the computer screen, I don’t feel like global variables would ever be tempting, unless it’s for constants.
This community makes more sense when you realize the majority of users are CS students.
Pointers hard!! LOL
Hey, don’t you group me in with people who have had a small amount of real training!
They’ve given me too many headaches…
I.e. you did use them, but learned the hard way why you shouldn’t.
Very likely OP is a student, or entry-level programmer, and is avoiding them because they were told to, and just haven’t done enough refactoring & debugging or worked on large enough code bases to ‘get’ it yet.
Is it really tempting for people? They’ve given me too many headaches when I’ve had to reformat or add functionality to files.
I don’t get it either. Why would you ever feel the need for them to begin with?
In software that’s already badly engineered. Either you do the work and refactor everything, or accept it’s probably not worth all the effort.
Unironically: For in-house scripts and toolboxes where I want to set stuff like input directory, output directory etc. for the whole toolbox, and then just run the scripts. There are other easy solutions of course, but this makes it really quick and easy to just run the scripts when I need to.
But those would be constants, not variables.
I typically don’t declare them as such - bring the pitchforks!
Everything’s a variable if you’re brave enough.
My
void*doesn’t care about yourconst!
Depends on what you’re doing. Functional programming has its own downsides, especially once you want to write interactive programs, which often depend on global states. Then you either have to rely on atoms, which defeat the purpose of the functional programming, or pass around the program state, which is janly and can be slow.
I personally go multi paradigm. Simpler stuffs are almost functional (did not opt for consting everything due to performance issues), GUI stuff is OOP, etc.
As with the sexual connotation here, the temptation is not rooted in long-term considerations like future maintainability
Well, if you’re writing something the user will be looking at and clicking on, you will probably want to have some sort of state management that is global.
Or if you’re writing something that seems really simple and it’s own thing at first but then SURPRISE it is part of the system and a bunch of other programmers have incorporated it into their stuff and the business analyst is inquiring if you could make it configurable and also add a bunch of functionality.
I also had to work with a system where configurations for user space were done as libraries setting global constants. And then we changed it so everything had to be hastily redone so that suddenly every client didn’t have the same config.
Most people suck at software engineering.
Plus, there’s always the temptation to do it the shitty way and “fix it later” (which never happens).
You pay your technical debt. One way or another.
It’s way worse than any gangster.
Not if you leave the project soon enough. It’s like tech debt chicken.
Then, at your new job, you see garbage code and wonder what dumbass would put global variables everywhere
You’re gonna see that even if you were pious at your own job. So you’re only wasting time.
That’s how this industry works ;)
Just create a global object and stuff your variable in there. Now you have a global singleton and that’s not a purely bad practice :D
Just call it “state management” and nobody will even care.
Not necessarily a bad practice if the singleton is immutable, and it’s provided via dependency injection for example.
As a hobby coder: “mmmhm, mmmm, mmhm… I know some of these words!”
Software dev is full of obscure keywords that describe otherwise pretty simple or basic concepts you stumble upon in practice naturally and that you probably already understand.
- singleton: a class/object that is designed to be single use, i.e. only ever instantiated with a single instance. Typically used when you use class/objects more for flow control or to represent the state of the program itself, rather than using it to represent data
- immutable: read-only, i.e. unchangeable
- dependency injection: basically when you pass a function or object into another function object, thereby extending their effective functionality, typically for modular code and to separate concerns.
Here’s one more of my favourite examples of such a keyword: memoization
Ahh yes memoization, the complicated way to say “remember this, I might need it again”
Important to contain all your mess to one side of the room, makes it easier to manage
Yeah yeah let’s put all the eggs in one basket
So you saying, just the tip?
Real enterprise programmers know that everything should be on the stack… so they declare a
List《void*》in main.But we might need to add more features in the future so it might not just be a list in a few years. Better encapsulate it in a few layers of abstractions just to be safe.
Real enterprise programmers know you can get another job in the next year or two so fuck best practice
Ah yes. Global Objects, AKA the thinnest of condoms, lol.
I do this all the time in Python by creating a class like
class Core: foo = "bar"
Obligatory, mutable global variables are evil.
The definition of a variable is that it’s mutable. If it’s immutable it’s constant.
There’s no ISO standardized definition for variable. People use that word with all kinds of meaning.
Waaaait a minute… isn’t it called a variable because the contents are, you know, variable?
This is needlessly obtuse. The definition of the word is that it’s non-constant. There isn’t an ISO definition of the word no, but there are many reputable dictionaries out there that will serve as an alternative.
Well, starting with the definition from algebra, where it’s not something allowed to vary…
I guess more people know about math than use imperative programing languages.
Except that’s exactly what it is allowed to in algebra.
Sure, in most equations you solve in early algebra school there is only one possible value for the variables. But in many equations there can be multiple, or even infinite. It’s an unknown, and the contents can vary (depending on other constraints, ie. The rest of the equation(s)).
There’s no time in algebra for your variables to vary.
When you have a non-unitary set of solutions, you have a constant non-unitary set of solutions.
I feel like it’s like pointers.
“Variable” refers to the label, i.e. a box that can contain anything (like *ptr is a pointer to [something we dont know anything about])
Immutable describes the contents, i.e. the stuff in the box cant change. (like int* ptr describes that the pointer points to an int)
Rust makes it very obvious that there’s a difference between constants and immutable variables, mainly because constants must be compile time constants.
What do you call it when a variable cant change after its definition, but isnt guaranteed to be the same on each function call? (E.g. x is an array that’s passed in, and we’re just checking if element y exists)
It’s not a constant, the contents of that label are “changing”, but the label’s contents cant be modified inside the scope of that function. So it’s a variable, but immutable.
As opposed to immutable variables
*confused screaming*
Or mutable constants…
int const golden = 1.618; int* non_constant = (int*)&golden; golden = 1.61803399;Casts are totally not a danger that should require a comment explaining safety…
And more generally mutable aliasing references of any sort are evil. Doesn’t mean they’re not useful, just that you need magic protection spells (mutexes, semaphores, fancy lock-free algorithms, atomics, etc) to use them safely. Skip the spell or use she wrong one, and the demon escapes and destroys all you hold dear.
You can do better, define intergalactic variables that share the same memory location across multiple programs so you can seamlessly pass variables from one to the next.
Is that you… Windows 95?
The ONE TRUE CONSTANT; even with an infinite universe, the value is the same in all of them.
Are the legends really true?
But not sand memory. It’s coars ena drogjh and irritating and gets everywhere.
Singletons:
Me: O_O;
Is it an orgy if multiple global variables are used in a multi threaded code?
not if everyone uses a Mutex. stay (thread) safe
Always practice safe stacks
I’ve once had a course involving programming and the lecturer rewrote the code, which we were usually using at our institute, making ALL variables global. - Yes, also each and every loop counter and iterator. 🤪
There’s no way you teach a uni course and do this kind of thing unless to demonstrate poor practice/run time difference. Are you sure you were paying attention?
Yes. He really thought it was efficient and would avoid errors if literally all variables were defined in a single Matlab function he called at the beginning of the script. We students all thought: “Man, are you serious?” As we didn’t want to debug such a mess, in our code, we ignored what he was doing and kept using local variables.
Ah I misread I thought it was specifically a programming course. I can expect this from a math prof.
Yes, it was a course on finite deformation material models. And no, you do really, really not want to declare each and every variable in your material subroutine globally for the whole finite element program.
Lecturers at universities tend to have little to no industry experience at all.
Productive research is also hard to imagine with such coding practice either.
That’s why when your job hires new people right out of college they have no idea what they’re doing and now must be trained how to actually do the job. “What, you mean we aren’t writing this enterprise application in python!?”
I’ve seen two teachers do this, both of them mathematics professors who teach programming for the extra cash. One uses C, the other Pascal.
Oh they were paying, way too much
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“But what if I put the whole program into a class and then made it a class wide variable?”
Sounds like the piece of legacy software I have do deal with.
I am not a programmer who knows how to program. I know this because global variables are how I fix most the issue I run into, but are constantly told this wrong.
I asked stable diffusion for a photo-realistic version of this image. This isn’t what I had in mind
Me putting everything in ‘public:’
Exhibitionist Devs be like.
Our Father, who art in Microsoft HQ,
hallowed be thy naming conventions;
thy architecture;
thy will be done;
on earth as it is in Linus Tech Tips.
Give us this day our daily StackOverflow.
And forgive us our 'sploits,
as we forgive those who trespass against our user stories.
And lead us not into temptation;
but deliver us from a thicket of global variables.
For thine is the irritating project manager, the power and the glory,
for ever and ever.
Or at least 7 years until obsolescence.
Amen.
the meme is spreading
Nothing wrong with global variables.
If anyone asks just say it’s the singleton pattern.
