Functional Programming in Haskell by Examples

https://github.com/caiorss/Functional-Programming

by bontoJR • 11 years ago

128 25 11 years ago

I'm curious how you feel Haskell has helped you. Do you actually use Haskell for a great percentage of your deliverable code or do you simply use it for ideas, experimentation and so forth?

embwbam4• 11 years ago

I've made 2-3 toy REST APIs, and now I'm working on a product using a Haskell backend that's bigger. https://github.com/seanhess/serials

I love it. I mean I could have done the same thing in node. But there's something about the workflow in Haskell. I need to add a new feature I didn't think of. But I don't have to refactor as aggressively because all my code is made up of little functions. I start hacking, my editor has a list of errors I still need to clean up. I clean them up, and it usually works the first try.

Or this morning I wanted to add a connection pool to my rethinkdb driver code. The resource-pool package gives you an awesome way to do it for anything. Without knowing about rethinkdb at all.

Also this morning I wanted to do some IO in parallel. I found several nice concurrency packages and threw one in without any refactoring.

It has its difficulties (deployment?) but I'm really enjoying it.

creichert3• 11 years ago

It has its difficulties (deployment?) but I'm really enjoying it.

Anything specific? What kind of environments are you deploying in?

qubitcoder• 11 years ago

Similar story here. I find I'm able to accomplish tasks which would otherwise be beyond my skill and intelligence. For example, even though C was the first language I learned, I can't imagine writing a parser in C after discovering the simplicity & readability of monadic parsing in Haskell. [1] Just compare that page with the parser/lexer for the Jq tool on the HN homepage (written in C).

A few months ago, I needed to retrieve JSON data from a list containing dozens of URLs. Fortunately, the "async" package handles this beautifully: [2]

  pages <- mapConcurrently getURL ["url1", "url2", "url3",...]

Once you learn the basic concepts of Haskell and get over the hump, you’re able do things with ease that would otherwise take many years to master in C++ [3]. Even the most advanced features of the language follow the same underlying principles & syntax.

My advice to those wanting to learn Haskell is simply not to give up. Keep coming back to it. Practice. Read other’s code. Over time, things will begin to click. And once they do, you’ll wonder why you struggled so much in the first place.

[1] https://www.fpcomplete.com/school/starting-with-haskell/libr...

[2] https://hackage.haskell.org/package/async-2.0.2/docs/Control...

[3] http://chimera.labs.oreilly.com/books/1230000000929/index.ht...

the_af• 11 years ago

I use it for my own experiments and never -- sadly -- for work, where my boss thinks Scala is just syntax sugar over Java, which is in turn merely syntax sugar over C. I don't think he has ever heard of Haskell, and I don't have the energy to have that conversation with him, when he is already so dismissive of Scala.

But I still have ghci installed at work, and I find it surprisingly useful to use Haskell to prototype (pure) functions for Scala! This is something I truly didn't see coming, but now I often find myself starting ghci when I want to see if some combination of folds or maps works the way I think it should, and for some reason it feels way more convenient than trying it in Scala.

sls• 11 years ago

C is just portable assembler, ask him why he's got people wasting company time and cpu cycles on such a thing. I'm sure you're targeting x86, time to put on your big boy pants.

fiveoak• 11 years ago

Nice reference. It's interesting how intuitive the examples are even though I've never learned a functional programming language before.

Ericson23145• 11 years ago

Learning functional programming is arguably more about unlearning all the terrible hoops other languages make one jump through.

M00n_Sl47r• 11 years ago

The grammar in this is a bit off. I'll probably submit a pull request with some edits, if that's something people do? I'm not sure about the etiquette surrounding grammar mistakes in a github repo.

creichert3• 11 years ago

I think it's a nice gesture as long as you are polite about it. I would be happy that someone read the content and wanted to help improve it.

jonreem• 11 years ago

Personally I am always thrilled to get grammar/typo fix pull requests to my projects. It means someone cared enough about the project to go through the effort of making a PR just to alleviate a small aesthetic problem!

bontoJR• 11 years ago

Definitely a good habit, I think more than the 50% of Github users are not English as mother tongues, so it's good to polish documentations, or like in this case, long texts. I always accept pull-requests for grammar improvements.

codezero• 11 years ago

Since I can't code for shit, I submit pull requests to fix grammar and spelling a lot.

The reactions are overwhelmingly positive. Just make sure to leave a nice comment.

titanomachy• 11 years ago

The GHCi command to enable multiline mode is `:set +m`, not `:set +s`. `set +s` enables profiling.

bbcbasic• 11 years ago

Great resource. I am learning Haskell. When I get more experienced at Parsec I'll consider a write up and send you a pull request.

Your monad section looks solid, although now I undestand them I can no longer tell if a tutorial is good or not :-)

Functional Programming in Haskell by Examples

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