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Search - "pure functions"
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This code review gave me eye cancer.
So, first of all, let me apologize to anyone impacted by eye cancer, if that really is a thing... because that sounds absolutely horrible. But, believe me, this code was absolutely horrible, too.
I was asked to code review another team's script. I don't like reviewing code from other teams, as I'm pretty "intense" and a nit-picker -- my own team knows and expects this, but I tend to really piss off other people who don't expect my level of input on "what I really think" about their code...
So, I get this script to review. It's over 200 lines of bash (so right away, it's fair game for a boilerplate "this should be re-written in python" or similar reply)... but I dive in to see what they sent.
My eyes.
My eyes.
MY EYES.
So, I certainly cannot violate IP rules and post any of the actual code here (be thankful - be very thankful), but let me just say, I think it may be the worst code I've ever seen. And I've been coding and code-reviewing for upwards of 30 years now. And I've seen a LOT of bad code...
I imagine the author of this script was a rebellious teenager who found the google shell scripting style guide and screamed "YOU'RE NOT MY REAL DAD!" at it and then set out to flagrantly violate every single rule and suggestion in the most dramatic ways possible.
Then they found every other style guide they could, and violated all THOSE rules, too. Just because they were there.
Within the same script... within the SAME CODE BLOCK... 2-space indentation... 4-space indentation... 8-space indentation... TAB indentation... and (just to be complete) NO indentation (entire blocks of code within another function of conditional block, all left-justified, no indentation at all).
lowercase variable/function names, UPPERCASE names, underscore_separated_names, CamelCase names, and every permutation of those as well.
Comments? Not a single one to be found, aside from a 4-line stanza at the top, containing a brief description of that the script did and (to their shame), the name of the author. There were, however, ENTIRE BLOCKS of code commented out.
[ In the examples below, I've replaced indentation spacing with '-', as I couldn't get devrant to format the indentation in a way to suitably share my pain otherwise... ]
Within just a few lines of one another, functions defined as...
function somefunction {
----stuff
}
Another_Function() {
------------stuff
}
There were conditionals blocks in various forms, indentation be damned...
if [ ... ]; then
--stuff
fi
if [ ... ]
--then
----some_stuff
fi
if [ ... ]
then
----something
something_else
--another_thing
fi
And brilliantly un-reachable code blocks, like:
if [ -z "$SOME_VAR" ]; then
--SOME_VAR="blah"
fi
if [ -z "$SOME_VAR" ]
----then
----SOME_VAR="foo"
fi
if [ -z "$SOME_VAR" ]
--then
--echo "SOME_VAR must be set"
fi
Do you remember the classic "demo" programs people used to distribute (like back in the 90s) -- where the program had no real purpose other than to demonstrate various graphics, just for the sake of demonstrating graphics techniques? Or some of those really bad photo slideshows, were the person making the slideshow used EVERY transition possible (slide, wipe, cross-fade, shapes, spins, on and on)? All just for the sake of "showing off" what they could do with the software? I honestly felt like I was looking at some kind of perverse shell-script demo, where the author was trying to use every possible style or obscure syntax possible, just to do it.
But this was PRODUCTION CODE.
There was absolutely no consistency, even within 1-2 adjacent lines. There is no way to maintain this. It's nearly impossible even understand what it's trying to do. It was just pure insanity. Lines and lines of insanity.
I picture the author of this code as some sort of hybrid hipster-artist-goth-mental-patient, chain-smoking clove cigarettes in their office, flinging their own poo at their monitor, frothing at the mouth and screaming "I CODE MY TRUTH! THIS CODE IS MY ART! IT WILL NOT CONFORM TO YOUR WORLDLY STANDARDS!"
I gave up after the first 100 lines.
Gave up.
I washed my eyes out with bleach.
Then I contacted my HR hotline to see if our medical insurance covers eye cancer.32 -
I AM SO FUCKING TIRED OF BUSINESS MOTHERFUCKERS USING TECHNICAL FUCKING BUZZWORDS LIKE THEY KNOW SHIT ABOUT TECH! THEY TRY TO BE FUCKING SMARTASSES AND ARGUE WITH DEVELOPERS LIKE GOD KNOWS WHY THIS FUCKING DOUCHE IS NOT THROWN IN /dev/null YET!
Ugh. He try to sound smart and argued with a unity game developer why the dev is not using "react" and "redux" in his game, purely because "since its the hype in 2016"... I was like really nigga?? FOR FUCKS SAKE Do some research before you say! Then he argued with a senior full-stack web developer on why they're using ES6 and not ES7, purely because he heard that ES7 is newer. When we try to explain we're not using decorator syntaxes since we use pure functions in our codebase, or how we haven't installed any ES7 babel plugins to transpile our code, he kept saying ES7 is newer and cooler and we must use it somehow... More to rant but i am fucking tired right now...14 -
Manager: I read an article today
Dev: oh here we go….
Manager: We must pivot to only functional programming, which means only using functions instead of classes
Dev: Actually functional programming is a bit more nuanced tha—
Manager: Any use of classes going forward is not allowed. Everything must use functions! Classes are an outdated way of programming, using classes is why we continue to miss our deadlines. Functional programming is lean, classes are waterfall.
Dev: What about the libraries we use? Many of those use classes
Manager: Wrap them in a function then, that way they are pure which is one of the requirements of functional programming. You would know that if you spent as much personal time as I do keeping up with the times.34 -
Let the student use their own laptops. Even buy them one instead of having computers on site that no one uses for coding but only for some multiple choice tests and to browse Facebook.
Teach them 10 finger typing. (Don't be too strict and allow for personal preferences.)
Teach them text navigation and editing shortcuts. They should be able to scroll per page, jump to the beginning or end of the line or jump word by word. (I am not talking vi bindings or emacs magic.) And no, key repeat is an antifeature.
Teach them VCS before their first group assignment. Let's be honest, VCS means git nowadays. Yet teach them git != GitHub.
Teach git through the command line. They are allowed to use a gui once they aren't afraid to resolve a merge conflict or to rebase their feature branch against master. Just committing and pushing is not enough.
Teach them test-driven development ASAP. You can even give them assignments with a codebase of failing tests and their job is to make them pass in the beginning. Later require them to write tests themselves.
Don't teach the language, teach concepts. (No, if else and for loops aren't concepts you god-damn amateur! That's just syntax!)
When teaching object oriented programming, I'd smack you if do inane examples with vehicles, cars, bikes and a Mercedes Benz. Or animal, cat and dog for that matter. (I came from a self-taught imperative background. Those examples obfuscate more than they help.) Also, inheritance is overrated in oop teachings.
Functional programming concepts should be taught earlier as its concepts of avoiding side effects and pure functions can benefit even oop code bases. (Also great way to introduce testing, as pure functions take certain inputs and produce one output.)
Focus on one language in the beginning, it need not be Java, but don't confuse students with Java, Python and Ruby in their first year. (Bonus point if the language supports both oop and functional programming.)
And for the love of gawd: let them have a strictly typed language. Why would you teach with JavaScript!?
Use industry standards. Notepad, atom and eclipse might be open source and free; yet JetBrains community editions still best them.
For grades, don't your dare demand for them to write code on paper. (Pseudocode is fine.)
Don't let your students play compiler in their heads. It's not their job to know exactly what exception will be thrown by your contrived example. That's the compilers job to complain about. Rather teach them how to find solutions to these errors.
Teach them advanced google searches.
Teach them how to write a issue for a library on GitHub and similar sites.
Teach them how to ask a good stackoverflow question :>6 -
"I'm almost done, I'll just need to add tests!"
Booom! You did it, that was a nuke going off in my head.
No, you shouldn't just need to add tests. The tests should have been written from the get go! You most likely won't cover all the cases. You won't know if adding the tests will break your feature, as you had none, as you refactor your untested mess in order to make your code testable.
When reading your mess of a test case and the painful mocking process you went through, I silently cry out into the void: "Why oh why!? All of this suffering could have been avoided!"
Since most of the time, your mocking pain boils down to not understanding what your "unit" in your "unit test" should be.
So let it be said:
- If you want to build a parser for an XML file, then just write a function / class whose *only* purpose is: parse the XML file, return a value object. That's it. Nothing more, nothing less.
- If you want to build a parser for an XML file, it MUST NOT: download a zip, extract that zip, merge all those files to one big file, parse that big file, talk to some other random APIs as a side-effect, and then return a value object.
Because then you suddenly have to mock away a http service and deal with zip files in your test cases.
The http util of your programming language will most likely work. Your unzip library will most likely work. So just assume it working. There are valid use cases where you want to make sure you acutally send a request and get a response, yet I am talking unit test here only.
In the scope of a class, keep the public methods to a reasonable minimum. As for each public method you shall at least create one test case. If you ever have the feeling "I want to test that private method" replace that statement in your head with: "I should extract that functionality to a new class where that method public. I then can create a unit test case a for that." That new service then becomes a dependency in your current service. Problem solved.
Also, mocking away dependencies should a simple process. If your mocking process fills half the screen, your test setup is overly complicated and your class is doing too much.
That's why I currently dig functional programming so much. When you build pure functions without side effects, unit tests are easy to write. Yet you can apply pure functions to OOP as well (to a degree). Embrace immutability.
Sidenote:
It's really not helpful that a lot of developers don't understand the difference between unit, functional acceptance, integration testing. Then they wonder why they can't test something easily, write overly complex test cases, until someone points out to them: No, in the scope of unit tests, we don't need to test our persistance layer. We just assume that it works. We should only test our businsess logic. You know: "Assuming that I get that response from the database, I expect that to happen." You don't need a test db, make a real query against that, in order to test that. (That still is a valid thing to do. Yet not in the scope of unit tests.)rant developer unit test test testing fp oop writing tests get your shit together unit testing unit tests8 -
Me and my team has been creating React components for the last two months. Today we realized that not a single component is done the Redux way (as pure functions), which means we have to refactor every component and the tests.
That's what you get for trying out new technology..3 -
The "unit" in unit test does not mean your ENTIRE APPLICATION. Ever heard of scope!?
I am amazed how often people write overblown test setups, mock hundreds of unrelated services, just to test one tiny bit of logic.
That bit of logic could have been a pure function.
For that pure function you could write a dead simple unit test. Given that input, I expect that output. Nothing more, nothing less. (It helps even more if the pure functions only accepts primitives, like string and numbers, or very simple immutable value objects).
No I don't care that the service is used by another service, as your mocked interaction also doesn't test the service as a whole but you just assume the happy case most of the time anyway. You want to test the entire application? Let's not use unit tests for that but let's use a different kind of test for that (integration test, functional tests, e2e-tests).
If you write code in a way that easily allows for unit testing, your need to mock goes away.rant unit tests test all the things tests you are doing it wrong tdd testing don't mock me unit test1 -
!rant
It feels so amazing to be able to divide a big ass method into multiple smaller ones that sometimes are even pure functions. <3 -
Why is it that virtually all new languages in the last 25 years or so have a C-like syntax?
- Java wanted to sort-of knock off C++.
- C# wanted to be Java but on Microsoft's proprietary stack instead of SUN's (now Oracle's).
- Several other languages such as Vala, Scala, Swift, etc. do only careful evolution, seemingly so as to not alienate the devs used to previous C-like languages.
- Not to speak of everyone's favourite enemy, JavaScript…
- Then there is ReasonML which is basically an alternate, more C-like, syntax for OCaml, and is then compiled to JavaScript.
Now we're slowly arriving at the meat of this rant: back when I started university, the first semester programming lecture used Scheme, and provided a fine introduction to (functional) programming. Scheme, like other variants of Lisp, is a fine language, very flexible, code is data, data is code, but you get somewhat lost in a sea of parentheses, probably worse than the C-like languages' salad of curly braces. But it was a refreshing change from the likes of C, C++, and Java in terms of approach.
But the real enlightenment came when I read through Okasaki's paper on purely functional data structures. The author uses Standard ML in the paper, and after the initial shock (because it's different than most everything else I had seen), and getting used to the notation, I loved the crisp clarity it brings with almost no ceremony at all!
After looking around a bit, I found that nobody seems to use SML anymore, but there are viable alternatives, depending on your taste:
- Pragmatic programmers can use OCaml, which has immutability by default, and tries to guide the programmer to a functional programming mindset, but can accommodate imperative constructs easily when necessary.
- F# was born as OCaml on .NET but has now evolved into its own great thing with many upsides and very few downsides; I recommend every C# developer should give it a try.
- Somewhat more extreme is Haskell, with its ideology of pure functions and lazy evaluation that makes introducing side effects, I/O, and other imperative constructs rather a pain in the arse, and not quite my piece of cake, but learning it can still help you be a better programmer in whatever language you use on a day-to-day basis.
Anyway, the point is that after working with several of these languages developed out of the original Meta Language, it baffles me how anyone can be happy being a curly-braces-language developer without craving something more succinct and to-the-point. Especially when it comes to JavaScript: all the above mentioned ML-like languages can be compiled to JavaScript, so developing directly in JavaScript should hardly be a necessity.
Obviously these curly-braces languages will still be needed for a long time coming, legacy systems and all—just look at COBOL—, but my point stands.7 -
Trying out pure functional programming in javascript. First few weeks: wow, this is so fresh, oop can die, etc. Now: this isn't readable at all! 😐5
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<rant>
I was once a pure server side developer. Then came full stack development. So in order to keep up with the competition, I had to brave through front-end development.
But goddamn javascript, make up your mind between functions, and “Objects”.
Also variable visibility. Goddamnit. I thought ES6 was widely supported. I was happy doing const and let bbut goddamn testing frameworks, grunt and shit. Can’t make up it’s mind to support it unitedly.
And lastly, IE. Goddamn it, why the fuck are you not supporting Promise by default. We’re fucking 2017. [insert slowpoke meme]
</rant>
One good thing though, I like the library vuejs.
Bad thing is, this is just the beginning of a much more upcoming headache.4 -
!rant
Continuation from: https://devrant.com/rants/979267/...
My vision is to implement something that is inspired by Flow Based Programming.
The motivation for this is two fold
* Functional design - many advantages to this, pure functions mean consistent outputs for each input, testable, composable, reasonable. The functional reactive nature means events are handles as functions over time, thus eliminating statefulness
* Visual/Diagrammable - programs can be represented as diagrams, with components, connections and ports, there is a 1 to 1 relationship between the program structure and visual representation. This means high level analysis and design can happen throughout project development.
Just to be clear there are enough frameworks out there so I have no intentions of making a new one, this will make use of the least number of libraries I can get away with.
In my original post I used Highland.js as I've been following the project a while. But unfortunately documentation is lacking and it is a little bare bones; I need something that is a little more featureful to eliminate boilerplate code.
RxJS seems to be the answer, it is much better documentated and provides WAY more functionality. And I have seen many reports of it being significantly easier to use.
Code speaks much louder so stay tuned as I plan to produce a proof of concept (obligatory) todo app. Or if you're sick of those feel free to make a request.3 -
Anyone else here who really enjoys writing pure functions or domain classes?
It's so amazing to be able to write dependency-less classes that have such simple, elegant logic and sometimes just a bunch of getters and setters. Pure functions with type hints are also one of my favorites.1 -
React, it's declarative way of doing things, and the functional programming methodology it prefers.
Realized how much I've moved on from for-loops and class/object instance to maps, filters and immutability/observers when I worked on a Laravel project after so long and found myself forced to do things in the, erm, "PHP" way, despite spending my initial year and a half of programming working exclusively in PHP.
Sure, there's Class Components and imperative techniques in React but I had blissfully settled into using the flexible nature of doing things enabled by both native JS and React, with hooks, Lodash/Ramda and (almost fanatically) pure functions1 -
You babble about pure functions but your intellectual peak was when you reinvented “the stranger”.2
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OOP is all about code reusability until you really want exactly the code Foo with non-pure functions in all your classes. You end up almost rewriting all subclasses' properties into the superclass to silence typecheckers. Is there no "I know what i'm doing, please just transpile/compile this piece of logic into these 20 places I need?" You end up doing it the functional way, dumping refs and params into some shared util function and have it do the job. I know, might as well have that one inherited also, but what's the point of adding more mess just for that ?2
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Trying to make a nodejs backend is pure hell. It doesn't contain much builtin functionality in the first place and so you are forced to get a sea of smaller packages to make something that should be already baked in to happen. Momentjs and dayjs has thought nodejs devs nothing about the fact node runtime must not be as restrained as a browser js runtime. Now we are getting temporal api in browser js runtime and hopefully we can finally handle timezone hell without going insane. But this highlights the issue with node. Why wait for it to be included in js standard to finally be a thing. develop it beforehand. why are you beholden to Ecma standard. They write standards for web browser not node backend for god sake.
Also, authentication shouldn't be that complicated. I shouldn't be forced to create my own auth. In laravel scaffolding is already there and is asking you to get it going. In nodejs you have to get jwt working. I understand that you can get such scaffolding online with git clone but why? why express doesn't provide buildtin functions for authentication? Why for gods sake, you "npm install bcrypt"? I have to hash my own password before hand. I mean, realistically speaking nodejs is builtin with cryptography libraries. Hashmap literally uses hashing. Why can't it be builtin. I supposed any API needed auth. Instead I have to sign and verfiy my token and create middlewares for the job of making sure routes are protected.
I like the concept of bidirectional communication of node and the ugly thing, it's not impressive. any goddamn programming language used for web dev should realistically sustain two-way communication. It just a question of scaling, but if you have a backend that leverages usockets you can never go wrong. Because it's written in c. Just keep server running and sending data packets and responding to them, and don't finalize request and clean up after you serve it just keep waiting for new event.
Anyway, I hope out of this confused mess we call nodejs backend comes clean solutions just like Laravel came to clean the mess that was PHP backend back then.
Express is overrated by the way, and mongodb feels like a really ludicrous idea. we now need graphql in goddamn backend because of mongodb and it's cousins of nosql databases.7