4ever-clojure VS talk-transcripts

I found this to be an awesome bridge between reading about the theory and actually writing code that works: https://4clojure.oxal.org/

This is for general Clojure, I’ve had a lot of fun and learned a lot from it (and the original): https://4clojure.oxal.org/

It's normal to apply methodology like this to clojure when transitioning from other languages. When I was first learning I did a bunch of exercises on 4clojure and my first attempts looked like this. Then I found loop from the standard library and I understood immutability but relied on loop to do anything to collections of things. Eventually, after looking at the answers, I started to get familiar with the standard library. Then my solutions started to look like the two line solution above.

4Clojure is here now: https://4clojure.oxal.org/. It runs locally in your browser.

Go to https://4clojure.oxal.org/ and solve some stuff. And don't learn any theory. You're thinking how a C# developer thinks and you think you need to learn some kind of packages by heart or something.

I learned by reading through a book, then working through problems on https://4clojure.oxal.org/. If you've got JS experience it won't take too much effort to pick up. Don't get too carried away with forming the perfect tail recursive pure functional monad or whatever. Get into just doing what you're trying to do quickly, then after you're competent, read other people's code to correct your style.

I'm only a couple months into learning Clojure too, but I found solving a problem myself and then seeing others solutions on this website https://4clojure.oxal.org/ was invaluable for learning to think like a clojurist.

I'm trying to learn Haskell and found https://4clojure.oxal.org/ very helpful. https://tryhaskell.org/ was also nice, but it is limited in scope as compared to its Clojure equivalent.

The actual address is https://4clojure.oxal.org/

Reminds me a little of hammock-driven development [1]

> the background mind is good at synthesizing things. It's good about strategy

[1] https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

Thank you for this recommendation. I've never heard of it before and now I'm reading: https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

It's giving me energy this Monday holiday(USA)!

race?

> [Audience reply: Sprinter]

> Right, only somebody who runs really short races, okay?

> [Audience laughter]

> But of course, we are programmers, and we are smarter than runners, apparently, because we know how to fix that problem, right? We just fire the starting pistol every hundred yards and call it a new sprint.

https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

>So this is 10x, a full order of magnitude reduction in (?) severity before we get to the set of problems I think are more in the domain of what programming languages can help with, right? And because you can read these they'll all going to come up in a second as I go through each one on some slide so I'm not going to read them all out right now. But importantly there's another break where we get to trivialisms of problems in programming. Like typos and just being inconsistent, like, you thought you're going to have a list of strings and you put a number in there. That happens, you know, people make those kinds of mistakes, they're pretty inexpensive.

[0] Video: https://www.youtube.com/watch?v=2V1FtfBDsLU

[1] Slides and transcript: https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

[2] Video https://www.youtube.com/watch?v=YR5WdGrpoug

[3] Slides and transcript https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

This is tangentially related to Puzzles-vs-Problems in Rich Hickey's Effective Programs

> Eventually I got back to scheduling and again wrote a new kind of scheduling system in Common Lisp, which again they did not want to run in production. And then I rewrote it in C++. Now at this point I was an expert C++ user and really loved C++, for some value of love. But as we'll see later I love the puzzle of C++. So I had to rewrite it in C++ and it took, you know, four times as long to rewrite it as it took to write it in the first place, it yielded five times as much code and it was no faster. And that's when I knew I was doing it wrong.

[...]

> So I mean for young programmers, if everybody's tired and old, this doesn't matter any more. But when I was young, when I was young, I really, you know, when you're young you've got lots of free space. I used to say "an empty head", but that's not right. You've got a lot of free space available and you can fill it with whatever you like. And these type systems they're quite fun, because from an endorphin standpoint solving puzzles and solving problems is the same, it gives you the same rush. Puzzle solving is really cool. But that's not what it should be about.

Talk: https://www.youtube.com/watch?v=2V1FtfBDsLU

Slides and transcript: https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

Using triggers + history tables (aka audit tables) is the right answer 98% of the time. Just do it. If you're not already doing it, start today. It is a proven technique, in use for _over 30 years_.

Here's a quick rundown of how to do it generically https://gist.github.com/slotrans/353952c4f383596e6fe8777db5d... (trades off space efficiency for "being easy").

It's great if you can store immutable data. Really, really great. But you _probably_ have a ton of mutable data in your database and you are _probably_ forgetting a ton of it every day. Stop forgetting things! Use history tables.

cf. https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

Do not use Papertrail or similar application-space history tracking libraries/techniques. They are slow, error-prone, and incapable of capturing any DB changes that bypass your app stack (which you probably have, and should). Worth remembering that _any_ attempt to capture an "updated" timestamp from your app is fundamentally incorrect, because each of your webheads has its own clock. Use the database clock! It's the only one that's correct!

Rich Hickey (creator of Clojure) references Polya several times in his classic talk "Hammock Driven Development". Here's a transcript:

https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

I've long been impressed by Hickey's problem solving skills, so I took much of this talk to heart, and even bought a copy of HTSI. Can't say it really helped me any more than Rich's talk (as a programmer) but I'm thinking I'll give it another look.

>Great product designs require no manual, and similarly, great interfaces need no documentation. Imagine having to read a manual on how to use a coffee mug.

This could not be more wrong.

Not everything is easy. If a library is addressing a complicated domain, solving by definition a complicated problem, it is fine if it requires some learning.

When did expertise and learning become bad things? If software is an engineering discipline, why would people in it ever promulgate the idea that any random cog can step in to any “engineer”s shoes?

Rich Hickey analogizes this mentality to the world of music, where it taken for granted that learning an instrument requires a lot of study:

“ We start with the cello. Should we make cellos that auto tune? Like, no matter where you put your finger, it's just going to play something good, play a good note.

“[Audience laughter]

“Like, you're good. We'll just fix that.

“ Should we have cellos with, like, red and green lights? Like, if you're playing the wrong note, you know, it's red. You slide around, and it's green. You're like, great! I'm good. I'm playing the right song. Right?

“ Or maybe we should have cellos that don't make any sound at all. Until you get it right, there's nothing.

“ [Audience laughter]”

https://github.com/matthiasn/talk-transcripts/blob/master/Hi...

You might find adjacent talks and speakers here ... https://github.com/matthiasn/talk-transcripts

Many languages merge the two concepts, and implement procedures as functions that return void. This may muddle/complect their distinction, causing programmers to call procedures from within functions, thereby making those functions into impure functions (meaning that they affect the world outside of themselves, through side-effects like I/O or mutating state). This should be avoided, especially if you care about debug-ability and Functional Core, Imperative Shell architectures (see Gary Bernhardt's Boundaries talk at 31:56) (which make testing your system easier, without mocking).