[JackMorgan]

I think Clojure is actually a lot safer by default than most people expect for a Lisp. Check out this comparison I wrote up between C#(or Java), F#, Clojure, and JavaScript on common edge case safety. http://deliberate-software.com/programming-language-safety-a...

In most ways I care about, Clojure is actually safer than C#. Now, if you're coming from an ML HM language, sure, you'll be taking a step back perhaps.

[smenko]

Clojure is horribly unsafe. I spent a year writing Clojure and half the time we were fixing bugs where someone had wrapped a map in another map or changed the shape of a data structure. For all that's worth, I'd rather use Javascript. To add insult to injury (the amount of wasted time on something that could be easily checked by a compiler and a sane type system) there's all the bad habits you acquire and the general lack of confidence in your code, which took a good six months after that to cure. I'm sticking with types now, thank you very much...

[JackMorgan]

Sounds like you needed Schema, which can ensure the shape and contents of a map as :pre and :post assertions in every function you annotate, then be turned off for production use. https://github.com/Prismatic/schema

That's why I come back to Clojure every time, if I need anything, it's available as a library. Need better typesafety? Just add in what you need with a macro or two. (Schema is not much more than that).

That's not really possible easily with Javascript, and Javascript has a lot more unsafe by default edge cases than Clojure. I'm not sure why if a mostly safe dynamic language bothers you, you'd now prefer an extremely unsafe dynamic language?

Lastly, types only give you a single dimension of safety, is this that exact shape, and ensuring I don't put a square peg into a round hole: both of which Schema adds in easily. Clojure is ALSO safe along many other dimensions, like thread saftey, immutably, null reference exceptions, etc.

[smenko]

80% of the problems I had to deal with (in a live, real-life Clojure system that had to be maintained and supported, not a hobby-happy-slappy-project-thing) were caused by putting square pegs in a round hole. You're telling me I need to get a macro-based library and add :pre and :post conditions that check the structure of a map, as opposed to using a language with types?! Really??? Oh, and guess what, I am sure there is a Javascript library that does that too...

[wz1000]

I agree with most of what you said, but

> Lastly, types only give you a single dimension of safety.

Dependent types can express a huge number of things, and are often limited only by your ability to describe what exactly you want.

[JackMorgan]

Absolutely right, I was just comparing with the dominant Java or Python.

Dependent typing is some cool stuff, I'd love to see more of it.

[pjmlp]

I have been following Idris, quite cool.

[kyllo]

Do you use a dependently typed language in production?

[wz1000]

I don't really use anything in production, I am just a learner right now :)

There are some people using some of extensions for Haskell inspired by "dependently typed" systems in production.

Dependent typing is an active research topic right now, and I doubt any fully fledged dependently typed language is used "in production".

However, I was just pointing out that it is possible for types to express a wide variety of things that we do not normally associate with them. Even without full dependent typing, Haskell types are wonderfully expressive and powerful.

[smenko]

Oh, god, thanks for reminding me about the whole agent/atom/ref hell - another reason I'd rather erase the whole Clojure experience from my brain altogether...

[nickik]

Jesus, maybe you were not able to read a clojure book befor you started. Its amazingly simple to explain how to write thread safe code with clojure, and pretty easy to add concurrency safly.

There are 3 concepts that are all diffrent, and a couple yours ago core.async was added. All in all thats a amazingly simple and powerful combination. Everybody I have heard is pretty happy with these tools. What is your problem?

[JackMorgan]

Agree to disagree. I do not enjoy the impossible to prove defensive coding around threads and callbacks. The core.async library made threading in Clojure for me to now be simple and pleasant compared to difficult to test mutexes and deadlocks.

[NhanH]

You're the first person I've seen that is vocal about having a truly bad experience with Clojure. Even from other people who prefer strongly typed language, I've mostly seen them expressing it as "not their taste", rather than actively dislike it. Do you mind sharing your experience and what was wrong with Clojure? You put js as an alternative, but in term of typing, js is borderline one of the worse type system out there.

[smenko]

Not as an alternative, but as similarly unsafe. It's funny to see how all the Clojure advocates bash Javascript...