Advanced programming languages
matt.might.net
matt.might.net
You can do just about everything in any mature language - after a while of so to say exploring the landscape for a number of years, its nice to just become deeply fluent in a couple of things. I know people love to talk about this language vs that and how language X will make you rethink everything and usually there is some truth to it but in the big picture its usually pretty trivial in terms of actually getting stuff done.
After some years learning "advanced" languages, and having mastered the constructs, the biggest problem becomes becoming acquainted with the libraries. It takes time to re-learn what to use to do something, not how to do it.
Another problem of mine is that a lot of time is spent writing/using bindings to other foreign code, or let alone re-implement the code in the current language. Or see your old code stop working because of new libraries, compilers, etc.
In the end, it feels like you're writing just for the sake of writing instead of actually doing something.
I disagree. If you're a startup, you're better off using a more mainstream language. I'm from India and if I start to find a good Haskell or Scala programmer I'll be looking for a long time and I'll be paying him/her a lot for those skills. Being a startup, you start small and its tempting to start using the bleeding edge technologies, but you must do a cost-benefit analysis; coders for PHP and Java are much easier to find and since the supply is more, the cost of skills will be less.
Bootstrapped startups should particularly be wary of using technologies that have a very small talent pool in their part of the world. Use new/rare technologies if the benefits of using them outweigh the hassle and expenses of maintaining and extending the team/codebase for it.
This will go into the costs column, and the reasons you use that particular tech. stack will go into benefit column. Weights and values are fairly subjective for each of the rows in the two columns and is very case specific.
What I wanted to point out was that there are a lot of factors to consider while choosing your tech stack, be it for academia, research, startup or enterprise. I disagree with this following statement:
>, and since you (probably) won't be working with an entrenched code base, you are free to use whatever language best suits the task at hand.
Size of the codebase is not the only criterion. (And to be fair to the author of this article, "task at hand" envelopes a lot of the other criteria).
PS: I found a good debate between Ryan Allen[1] and Michael Wales[2] debating the criteria on which to choose PHP or Ruby, a lot of them can be translated to a general tech stack choice. I've submitted it to HN here[3] and direct link here [4].
[1]http://twitter.com/ryanfaceryan
[3]http://news.ycombinator.com/item?id=3446180
[4]http://net.tutsplus.com/articles/general/language-war-php-vs...
Sorry, if the link was already posted on HN sometime in the past.
Edit: Formatting
No. of programmers for the former > No. of programmers for the latter
PS: I'm very impressed with tech community in Pune in general. Very vibrant, diverse and passionate.
By your simple equation, you'd be hiring only Turbo C programmers :D
But I do agree with you - if your startup is not primarily a technology one, then maybe it doesn't matter. Throw enough people at it and it might just work
In general, if you need to find a good programmer for any language (Python, JavaScript, Java, ...), you will be searching for a long time. The only difference is that with Haskell, OCaml and other advanced languages, usually the first programmer you will find is already very good.
Are you part of the 99%? It irks me when people make pompous statements like this.
pomp·ous/ˈpämpəs/Adjective:
Affectedly and irritatingly grand, solemn, or self-important: "a pompous ass".I'm not saying you can't get the job done in a mainstream language; but I postulate that the mindset and attitude towards code of a good Haskell or Scala programmer is vastly different from your less expensive PHP or Java programmers. Some want to push the limits of what's technologically possible and others just want their paycheck by the end of the month; they are in both camps; are they evenly distributed?
What about libraries and code-bases available to the programmer? Legacy code might not be a concern, but what about having to reinvent wheels?
I think no language is advanced enough to be used alone for everything. Steve Yeggie said that once a time at Amazon the only languages allowed were Lisp and C. It makes sense: an high level language plus a low level one. Those languages which try to encompass too much become too complex and hard to use effectively (think about C++).
When I started in 1997 (before Yegge) there was lots of C and Perl but no Lisp, at least not in the central repo. There were restrictions on Perl. The DBAs wouldn't let us use it to insert data in the database. Shel didn't care much for Perl. He might have warmed to it a little bit when he discovered it supported closures; I remember him sending a msg to the software alias about it.
Eric Benson had been a principal at Lucid, though I didn't know it at the time. Once he gave a class to the perlhackers on how to write code. The advice, as I recall, was to put "use strict;" at the top of our scripts and to start every function by shifting all the arguments into local variables. Eric Benson wrote the initial version of the "customer who bought this also bought..." code, and he used Perl, not Lisp. I'm sure he thought about the problem in Lisp terms, tho.
> A bounded lattice is a mathematical structure that has a least element (bot), a greatest element (top)
And then proceeds to define a typeclass that does not satisfy the definition:
instance (Ord k, Lattice a) => Lattice (Map k a)
where top = error $ "Cannot be represented.
You can't even fix the definition of top, since union of arbitrary Maps is not bounded, e.g. there is no finite Map String foo (map with String keys) that is a superset of every Map String foo.
You could change Lattice to a weaker structure, but I think it would be better to present a simpler typeclass like Show or Ord.
I'm not convinced that I would be more productive developing say a web app , database app or game using say Haskell rather than Java or Python especially since a large amount of programming is all about state and side effects.
I'm not against learning a pure functional language as a way to improve your programming especially for concurrency or to solve specific problems.
Are there any large pieces of software outside of academia that are written primarily in functional languages?
If you're asking about places where FP is often used, I know it's big in finance (though I have no idea what those guys are up to).
The haskell web development space has also gotten to a pretty mature point. I think you'd have no problem building a web app with Yesod or Snap.
http://www.yesodweb.com/ http://snapframework.com/
You could also check out http://cufp.org
I've heard this a few times (mostly from the Scala crowd) but very little data to back it up, so I'm still skeptical.
There are several prop trading firms (Jane Street, Tsuru Capital, etc) that use functional languages heavily. Also, many of the big banks (Credit Suisse, Deutsche Bank, Barclays, etc) use some FP in production, but as far as I know it's only used by small, strategic groups. FWIW I've interviewed or applied at many of those big banks in Tokyo and not one of them ever mentioned interest in FP skills. As far as I could gather the typical developer there doesn't know or is not interested in FP.
The naughty dog game studio used a form of lisp in their games starting with Crash Bandicoot until they got purchased by Sony(I think). Though, the language was much more imperative in nature instead of functional.
Autocad had autolisp built into it.
http://en.wikipedia.org/wiki/Game_Oriented_Assembly_Lisp
I don't know of any others off the top of my head.
I see allot of functional DSLs (Excel for example + autocad as you pointed out).
Was crash bandicoot written in Lisp or was this just an internal DSL used for certain operations?
I don't have anything against functional languages and I'm sure all good developers should know at least 1 but the article seems to suggest that everyone should use them all the time.
There are more important things than having an expressive language, I use allot of Java which is seriously non expressive in many ways but I have more confidence in it to solve the category of problems I deal with than any other language that I have tried thus far.
http://www.gamasutra.com/view/feature/2985/postmortem_naught...
As front page keeps changing and reordering, the "Next page" link after some time becomes meaningless, so maybe it's because of that.
HN doesn't look as an outstanding piece of software.
Merging discussions is not allowed.
No checking of duplicate links, if I'm not mistaken.
Non foldable threads.
No way to watch threads of comments.
No notifications when someone answers a comment of yours.
After you have submitted a comment, it just reloads the page instead of taking you right were your fresh comment is, to allow you to continue reading where you left.
Item lists in comments are not handled.
How do you format text in comments? Nobody tells you.
Basically, if you take HN at face value, it does not look like a smart piece of software. Maybe under the hood there is a mind-bending piece of AI, but as long as it doesn't care about users, users will never know about it.
It will vote for the original if the urls are the same when you submit it. This is a simple check though.
Foldable threads are client side.
I wish it had notifications.
The other items re formatting could be easily fixed on the submission page.
IANA web developer, but...
Doesn't web development typically put state into a database system instead of the scripts the server runs to generate the requested pages? It seems reasonable enough to have a function that takes a page request as input, calls some other functions to look up info from the database, then constructs and returns a page and a sequence of changes to make to the database.
Not to mention if you are using Comet or something where you hold a request open for a long time and push and pull allot of data some of which may not be persisted immediately.
Sure you can probably write your controller logic in a pretty functional way but then you probably end up moving your messy logic into stored procs or something else.
Is this an issue with race conditions, or with alternating between reading and writing the state during a single request, or both, or something else entirely?
You may also take input from other sources than a database
This doesn't seem like it should make a difference: you write a function to get the necessary data from whatever source, then call that function in the page request handler (OK, yes, I/O is technically a side effect).
I agree that the processing you do with that data might require some significant rethinking, depending on how it was written/planned out before (sure, state-passing style is always there, though I don't enjoy doing it... really though, I've found that a lot of what I was used to doing imperatively is not all that awkward to do functionally).
Not to mention if you are using Comet or something where you hold a request open for a long time and push and pull allot of data some of which may not be persisted immediately.
What's the conventional way to do this in an imperative language?
Usually reading and then writing some state followed by waiting briefly to see if another thread will change the same value, if it does use then do something with the new value and return that to the request.
I agree that the processing you do with that data might require some significant rethinking, depending on how it was written/planned out before (sure, state-passing style is always there, though I don't enjoy doing it... really though, I've found that a lot of what I was used to doing imperatively is not all that awkward to do functionally).
Depends on how much more difficult it is , does it just require and adjustment of thinking to a new paradigm or is doing everything harder? I'm thinking of stuff like Haskell Monads here. I admit I have not much functional knowledge beyond some basic scheme so I'm curious about this.
What's the conventional way to do this in an imperative language?
I guess allocate stuff on the heap which other threads can modify, use monitors to control concurrent access.
Depends on how restrictive your language is. Scheme makes it a lot of things easy, e.g. a sequence of statements is often easy to express with begin/let/let* , whereas Haskell is pickier about use of side effects. The biggest hurdle I had in learning scheme was getting used to using a recursive function where I would normally use a loop.
(let* [(x (... DB query ...))
(y (... API query based on x ...))]
(begin (... write some state based on x and y ...)
(... wait a bit ...)
(... read the same piece of state ...)
(if (... it is unchanged ...)
(... then ...)
(... else ...))))
I'm launching a small Haskell-based product called EventSource HQ (http://www.eventsourcehq.com) taking advantage of just this.
Handling state across threads in Haskell is not a problem at all. Haskell is not bad or complex when it comes to mutable state, it's just very explicit about it. When it comes to doing stuff the involves multiple threads this is a huge advantage.
Haskell is complex in the sense that it brings a whole bunch of new abstractions to the table that can take a lot of work to get a hold of. But while this can make for a steep learning curve, it also comes with a huge payoff, since these abstractions are very powerful.
Stuff like Iteratee's and Enumerators or the newer Conduits can be tough to wrap your head around, but once you do the power of composable abstractions over IO streams can be extremely useful.
If I'm not mistaken, Jane Street is another functional programming shop: http://www.janestreet.com/
These are companies using OCaml: http://mirror.ocamlcore.org/wiki.cocan.org/companies.html
Haskell isn't about avoiding side effects. It's about managing them.
Seriously, it's time to drop this criticism. Obviously Haskell can "do things". It may not have thousands and thousands of apps of every type, but when it has an X window manager, a DVCS, and a few web frameworks under its belt, it clearly isn't about "not having side effects". (Nor is that a complete list; my point is that is sufficient evidence to show that things can be done, not a complete app list.)
Every functional language you've ever heard of has reasonably serious apps, but I'm not sure there's one yet where you won't encounter at least one of 1. a tooling problem (Erlang, Haskell) or 2. an impedance mismatch between the tooling and the language (Scala, Clojure). Time is correcting this problem rapidly, but if you don't feel like being on the cutting edge (and that's a fine position to take), I wouldn't push them on you. (But I would say that all four of those languages I mentioned are indeed the cutting edge and have come off the bleeding edge. Real work can be done in them if you stick to their strengths, but you may hit some bad error messages, or road blocks you'd normally just download your way around.)
"...especially since a large amount of programming is all
about state and side effects."
In terms of writing algorithms, you'd be amazed at how little needs to be expressed in terms of manipulation of state. It feels natural to write stateful functions if you've spent large amounts of time programming in stateful languages, but that has more to do with your familiarity than a property inherent in the problem. If you were immersed in Scheme, you might say, "...a large amount of programming is about function definition and application", just like if you were immersed in Forth, you might say, "...a large amount of programming is about stack manipulation." You certainly could use e.g. Scheme as language for general-purpose programming, and I suspect the problems that would arise would not be problems with functional programming, but rather an unfortunate lack of modern libraries for things like Unicode handling.
I can quite happily write programs in python without any real side effects, indeed as you suggest I usually try and divide my functions between those which have side effects and those which don't. So what advantage would I get for picking haskell instead? Other than marginally shorter programs?
FP seems to be picking up steam recently, is this just because we are doing more computation in the cloud and CPUs are getting more cores rather than more raw clock speed or am I missing something?
On top of this, having professionally written C/C++ for years in the embedded systems space I can say that Monads for IO is not awkward. In fact, it feels far more powerful because you are not limited to the awful semicolon operator for chaining effects.
Lastly FP != slower (even on single core). I agree Haskell can be hard to reason about performance wise at times due to choosing lazy by default. However, have you ever heard of Sisal? Many strict by default FP languages are quite fast, however they sacrifice purity. But to be honest, with experience Haskell can be damn fast also.
1. Java is not really evolving, people are frustrated
2. Multicore is difficulte and FP claim they are better at it.
3. Complexety of ever bigger codebases
4. Java Script not longer the worst language in the world, people start to understand whats powerful about it and want to know what more is possible.
So, why didn't Haskell become more popular earlier? I think that's simple: the GHC compilers has improved tremendously over the past years, Hackage has grown considerably, and there are now more books oriented at practical programming.
I probably wouldn't use it for anything today, but in another couple years maybe. The ecosystem seems like it's reaching critical mass.
The F# based WebSharper web framework: http://websharper.com/. WebSharper is based on the work of Philip Wadler, et al: http://groups.inf.ed.ac.uk/links/formlets/
Here's another article by Philip Wadler on Formlets: http://homepages.inf.ed.ac.uk/wadler/papers/formlets-aplas/f...
Of course Microsoft uses F# for Bing data processing.
Some Examples: I think Twitter uses Scala(see above) for a number of their back-end services (see http://blog.redfin.com/devblog/2010/05/how_and_why_twitter_u...). Foursquare uses scala at least on the front end http://news.ycombinator.com/item?id=1139062 . This page has a few other big success http://www.scala-lang.org/node/1658.
Haskell has pandoc(http://johnmacfarlane.net/pandoc/) a cmdline tool to convert beetween markup formats(also a library with binding to several languages) I think it supports a wider range of formats/fidelity then alternatives.
Ocaml: MLDonkey is an open source eDonkey2000 client Coq – a interactive theorem prover.
Ocaml
Have you tried? Why do you think your baseless assumptions are interesting?
I agree with you. But to play devils advocate, if its so large and deep, why do I only hear about Haskell and Scala when language-geeks talk about "advanced" programming languages? Looking at the wikipedia link you provide, there's a list of bullet points by decade: 7 things worthy of a bullet in the 60's, 7 in the 70's, 4 in the 80's, 2 in the 90's and 0 in the 00's and 10's. Has nothing interesting happened lately? Is Haskell as good as it gets?
It's debatable just how good Haskell and similar languages are. Like any language, it has its ardent fans and bitter detractors.
As for development of "advanced programming languages" in general, if you are interested in what's out there, I strongly recommend you browse the archives of the "Lambda the Ultimate" weblog:
http://lambda-the-ultimate.org/
There are a lot of very knowledgeable language designers on there, and news of advanced language features and new languages filters through there all the time. The blog is not as active as it once was, but the archives are still very much worth studying.
Another great resource is the old c2 wiki. Here are some relevant starting points:
http://c2.com/cgi/wiki?search=haskell
http://c2.com/cgi/wiki?search=lisp
http://c2.com/cgi/wiki?search=scheme
Finally, just hang around HN for a while, and you'll see plenty of posts discussing new "advanced" languages. The HN archives are also worth browsing through.
Seriously, though, it takes time. Lisp had higher-order functions and garbage collection long before they became mainstream. The type systems used in OCaml and Haskell were discovered in the 70s. Maybe in 10 years we'll see what of the 90's ideas become really valuable (or crappy but mainstream...).
* Haskell (functional programming, purity)
* Prolog (logic programming)
* Erlang (actor based concurrency)