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I learned Haskell in just 15 years

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Re: I learned Haskell in just 15 years

#21

Post by y1n0 »

mrkeen wrote: post #15
nequo wrote: post #6

Earlier quoted context omitted.

That’s interesting because F#’s OOP, as someone who knows neither C# nor Java, makes it more intimidating to me than OCaml. Also interesting that when FP is mentioned, Hindley-Milner is implicitly understood to be part of FP too even though it doesn’t have to be. Clojure emphasizes immutability and FP but with dynamic typing and everything that comes with that.

> Clojure emphasizes immutability Is "emphasizes" just another word for second-class support? C++ emphasizes the importance of memory safety.

Immutability is definitely first class in clojure, but you can work with mutable structures when you need to.

Re: I learned Haskell in just 15 years

#22

Post by kreyenborgi »

sidkshatriya wrote: post #4
initplus wrote: post #3

Earlier quoted context omitted.

Yes - the value of functional programming isn't that working in OCAML, or F#, or Haskell is 10x as productive as other languages. But that it can teach you worthwhile lessens about designing software that apply equally to imperative languages. Modelling the business domain, reasoning and managing side effects, avoiding common imperative bugs, these are all valuable skills to develop. F# is a great language to learn,…

> Yes - the value of functional programming isn't that working in OCAML, or F#, or Haskell is 10x as productive as other languages. This is not true in my personal experience. As has been famously said (paraphrased): Functional programming makes tough problems easy and easy problems tough. In other words the value of functional programming depends on your domain.

> makes tough problems easy and easy problems tough

And because of mutual recursion, that means that tough is easy (and easy tough). In other words, if we call the class of tough problems T and easy problems NT, we have T==NT, given FP.

Re: I learned Haskell in just 15 years

#23

Post by beders »

munchler wrote: post #2

Cute. All kidding aside, though, functional programming is worth the effort to learn, and it doesn't actually take 15 years. The payoff is at the end of the article: "It’s quite natural to program in Haskell by building a declarative model of your domain data, writing pure functions over that data, and interacting with the real world at the program’s boundaries. That’s my favorite way to work, Haskell or not." Haskel…

I feel the same pay-off - but arrived at that point via Clojure. Immutable-first, aim for purity, ability to drop out of it when necessary.

As stringent as you need it to be (static vs. dynamic types vs. specs), as flexible as you want it to be.

Re: I learned Haskell in just 15 years

#24

Post by kreyenborgi »

leononame wrote: post #16

Great read! Can anyone here recommend a good resource for learning Haskell that's in the style of "Text-Mode Games as First Haskell Projects"? Haskell has been on my radar since forever, and I've got some FP concepts internalized by making a side project in F#, but I have no idea what a monad really is and a fun prohect to code along might be perfect.

https://learn-haskell.blog/

> In this book, we will implement a simple static blog generator in Haskell, converting documents written in our own custom markup language to HTML.

> We will:

    Implement a tiny HTML printer library
    Define and parse our own custom markup language
    Read files and glue things together
    Add command line arguments parsing
    Write tests and documentation
> In each chapter of the book, we will focus on a particular task we wish to achieve, and throughout the chapter, learn just enough Haskell to complete the task.

Re: I learned Haskell in just 15 years

#25

Post by Skinney »

TrackerFF wrote: post #12

What's the benefit of learning a PURE functional programming language, opposed to just using a language which has adapted the best bits and pieces from the functional programming paradigm? Given that you want write code that sees "real world" use, and is used to handle data and events from the real world. To me, sometimes the line between optimized code and intellectual curiosity blurs.

> What's the benefit of learning a PURE functional programming language

1. It makes it easy to learn how to structure a program in a pure way, which is hard to do in languages that offers you a easy way out.

2. Since "everything" is pure, writing tests is easier.

3. You know for certain that if you discard the result of a function call, all the side-effects that it would normally trigger would be stopped as well.

4. A program where all side-effects are guaranteed to be pushed to the boundaries, is a program that's easy to reason about.

> a language which has adapted the best bits and pieces [...]

Languages that has adapted to best bits and pieces from X, Y, Z tend to be worse than a language specifically for X, Y and Z.

For instance, Java supports functional programming but functional programming languages are much better at it because they were designed for that specific paradigm. In the same vein, sure you can write pure programs in F#, but not as easily as in Haskell that was designed for doing just that.

> and is used to handle data and events from the real world

Pure code really only means (in practice) that side-effects are controlled, which is generally very helpful. It forces you to structure programs in a way which makes it easy to pinpoint where data is coming in, and where data is going out. It also makes for easier testing.

Being able to know, definetly, the answer to "will calling foo perform a network request" without having to read the source for foo is quite nice, especially when dealing with third-party code.

All this said, I probably wouldn't begin with Haskell. A language like Elm is much better suited for learning writing pure programs.

Re: I learned Haskell in just 15 years

#26

Post by elbear »

TrackerFF wrote: post #12

What's the benefit of learning a PURE functional programming language, opposed to just using a language which has adapted the best bits and pieces from the functional programming paradigm? Given that you want write code that sees "real world" use, and is used to handle data and events from the real world. To me, sometimes the line between optimized code and intellectual curiosity blurs.

What's the benefit?

You start to see functions as self-contained things, as lego blocks. All the logic of the function is there in the function. It only works on values it receives as inputs (it can't read global variables). It only outputs its results (it doesn't assign them to some other global variable that you have to track down).

This makes your code modular. You can add a function in a chain of functions, if you want to perform an extra transformation. Or, you can replace a function with a different one, if you want to change something about the logic.

Re: I learned Haskell in just 15 years

#27

Post by kreyenborgi »

TrackerFF wrote: post #12

What's the benefit of learning a PURE functional programming language, opposed to just using a language which has adapted the best bits and pieces from the functional programming paradigm? Given that you want write code that sees "real world" use, and is used to handle data and events from the real world. To me, sometimes the line between optimized code and intellectual curiosity blurs.

Don't think of it as being all pure code, think of it as tracking in the type system which parts of your code may launch the missiles and which parts can't. Given the following program,

    main :: IO ()
    main = do
      coordinates  IO  ()
    launch = -- TODO
    
    calcTrajectory :: Coordinates -> Trajectory
    calcTrajectory = -- TODO
I can look at the types and be reasonably certain that calcTrajectory does no reads/writes to disk or the network or anything of that sort (the part after the last arrow isn't `IO something`), the only side effect is perhaps to heat up the CPU a bit.

This also nudges you in the direction of an Functional Core, Imperative Shell architecture https://www.destroyallsoftware.com/screencasts/catalog/funct...

Re: I learned Haskell in just 15 years

#28

Post by IshKebab »

munchler wrote: post #2

Cute. All kidding aside, though, functional programming is worth the effort to learn, and it doesn't actually take 15 years. The payoff is at the end of the article: "It’s quite natural to program in Haskell by building a declarative model of your domain data, writing pure functions over that data, and interacting with the real world at the program’s boundaries. That’s my favorite way to work, Haskell or not." Haskel…

I feel like functional programming is pretty trivial. It's pure programming that is very difficult.

They're often conflated because Haskell is pure and functional and probably the most talked about heavily functional language.

I certainly didn't know that impure functional languages like OCaml existed for ages.

Re: I learned Haskell in just 15 years

#29

Post by mrkeen »

y1n0 wrote: post #21
mrkeen wrote: post #15

Earlier quoted context omitted.

> Clojure emphasizes immutability Is "emphasizes" just another word for second-class support? C++ emphasizes the importance of memory safety.

Immutability is definitely first class in clojure, but you can work with mutable structures when you need to.

This is sounds like memory safety in C++.

https://www.infoworld.com/article/3714401/c-plus-plus-creato...

Re: I learned Haskell in just 15 years

#30

Post by foobazgt »

kreyenborgi wrote: post #27
TrackerFF wrote: post #12

What's the benefit of learning a PURE functional programming language, opposed to just using a language which has adapted the best bits and pieces from the functional programming paradigm? Given that you want write code that sees "real world" use, and is used to handle data and events from the real world. To me, sometimes the line between optimized code and intellectual curiosity blurs.

Don't think of it as being all pure code, think of it as tracking in the type system which parts of your code may launch the missiles and which parts can't. Given the following program, main :: IO () main = do coordinates IO () launch = -- TODO calcTrajectory :: Coordinates -> Trajectory calcTrajectory = -- TODO I can look at the types and be reasonably certain that calcTrajectory does no reads/writes to disk or the…

FYI, I think you meant functional core, imperative shell.
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