From C# on Mono, to Clojure on the JVM

http://blog.agilehead.com/content/from-c-on-mono-to-clojure-on-the-jvm/

by mariorz • 17 years ago

43 32 17 years ago

blog.agilehead.com

abdulhaq3• 17 years ago

His opinions about the merits of python vs lisp vs clojure seem based more on rumour and the current lisp/clojure kool-aid than on hard-earned hands-on experience. I love Lisp when coding by myself and Clojure sounds really interesting, but Python is currently rock solid and a better fit for real-world team based development. And it's fine for functional programming, contrary to the strange opinion in the article that Guido is well-known to be 'against' functional programming !?

mattrepl• 17 years ago

Is there a significant reason, other than preference, that Python is a "better fit for real-world team based development" than Clojure or any Lisp dialect?

Python supports functions as objects that can be passed around, but that does not make it a FP language. Functional programming is about constraining mutability and declaring what you want, now how. Python does not lend itself to that style of programming.

Guido has spoken out against map/reduce/filter, lambda, and TCO in Python so many people interpret that as him disliking FP. I think it has more to do with Guido's aesthetic and Python's design principles than anything else.

yummyfajitas4• 17 years ago

I'll give one reason why Python may be better for team development than clojure/lisp: powerful macros. They do make it harder to reason about code you didn't write. In Python, you can look at the inside of a function and have some idea what it is doing.

"It's doing kwyjibo(i,v) to all the i in zqmfgb. Now, lets see what v and zqmfgb are."

In clojure, that isn't always the case. An example: recently, I was trying to write an OpenGL app in Clojure. I found the following code on the net (pretend it was written by a team member):

    (doto obj
        (.glBegin ...)
        (.methods ...)
        (.glEnd))

I decided I wanted to factor out the (.glBegin ...) and (.glEnd). Aha, this is a job for macros!

    (gl-begin-end body) ; this should macro expand to:

    (do
        (.glBegin ...)
        body
        (.glEnd))

This would just fit inside the the doto, and be exactly what we need. The problem is that doto significantly modifies it's contents:

    (doto obj
        (.method x)
        (.method y))

    (clojure.core/let [G__1206 obj] 
        (.method G__1206 x)
        (.method G__1206 y) G__1206)

So I got this: (doto obj (gl-begin-end body))

    ;macroexpand once
    (clojure.core/let [G_1725 obj] 
        (gl-begin-end obj body))

    ;macroexpand twice
    (clojure.core/let [G_1725 obj] 
        (do
             (.glBegin ...)
             G_1725
             body
             (.glEnd)))

Obviously this didn't work.

In this case, the problem is me: `(doto obj body)` is idiomatic clojure, and I should have known about it. On the other hand, `(kwyjibo obj obj2 body)` could be very hard to figure out and modify.

I should, however, raise the caveat that I'm not a good enough lisp programmer to know if this is really a problem in practice.

abdulhaq3• 17 years ago

Python is better than the lisps for team based development, IMO, primarily because you can't write your own language in python. In a team you're normally working on long-lived code of medium - large projects (e.g. over 100k lines, over a period of 1 - 5 years). You need to be able to quickly grok how to maintain older code written by someone else. Python's mantra "there's only one way to do it" means that is more likely to be possible than it is in one of the lisps. However I have to admit that that is conjecture on my part, not having worked on a large team with a lisp project.

ubernostrum• 17 years ago

Well.

The whole "people don't write applications in Lisp, they use Lisp to write a new language and then write applications in that" point has been brought up already, so I won't try to argue its pros or cons (thankfully somebody else can get flamed from both sides over it).

I will say that I think Python does something interesting, in that it removes some of the stupidest problems teams usually run into. Consider projects written in C or C-like languages: hugely disproportionate amounts of time are dedicated not to actual issues of how to design applications, but to things like where to put braces and how to use whitespace. Python sidesteps a lot of that petty bickering because the requirements of syntactically valid Python impose consistent solutions to those debates from the start.

Also, culturally, Python programming style tends to go quite a bit beyond that. For example, most large projects simply use PEP 8 as their style guide, doing away with an even larger class of stupid infighting.

As to FP and whether Python hates or supports it, unfortunately it is the case that if you put five FP proponents in a room you'll get at least twelve mutually-exclusive definitions of FP. So I think that tends to be a rather silly debate to have :)

khandekars• 17 years ago

Thanks. Having actually used Mono on Linux, he shared some interesting observations. Clojure surely looks promising, but Python or Scala can be equally fine choices as of the moment.

DanielBMarkham• 17 years ago

I must have missed something about this platform transition.

First and foremost, where are his customers in all of this? Languages are tools to reach goals for humans. What goals did he not accomplish because of using Mono and C#? What specific business objectives were impaired? How would these goals be more easily achieved now?

Secondly, I find it odd that a position on patents would work it's way into a tools choice without there being some kind of firm evidence of trouble. Did Microsoft's decision change the technical environment? Were there problems with building or maintaining code? Or did Microsoft just tick off the open source community and that made him decide to change? Perhaps I missed something, but it was sounding like he was making platform decisions based on some kind of popularity contest or imagined threat. Like I said, I'm ignorant here. Perhaps Microsoft's move has real-world ramifications? If so, I didn't see them in the article.

Finally -- what about F# on mono? You've got all the functional programming you can throw a stick at. And you've got objects as well if you want them. I didn't see that come into consideration at any point, although it seemed relevant -- if his interest was functional languages.

I also found the comment about the .exe and .dll file extensions weird. So people think they're strange? So what? Once again, what does this practically mean to developers or maintainers? Did it cause real problems? Or does it just look bad?

Language and platform discussions always come down to defining criteria: you determine what criteria are important to you and make your decision around that. Sometimes it's speed or conciseness. Sometimes it's availability of programmers. Sometimes it's ability to grow and maintain large code bases.

Whatever the criteria, you have to establish them and the stick to them. I prefer "ability to provide value to customers as quickly as possible" over things like "ability to run in parallel" or "ability to easily find programmers", but to each his own. There are great arguments to be made for all kinds of criteria.

What I didn't see was what exact criteria was being used. Sounded more like somebody just chasing whatever was trendy at the time.

rbanffy5• 17 years ago

"How would these goals be more easily achieved now?"

I feel the guy's pain. Of all technologies we use at our company, the Java folks are the ones that take the longest to deliver a functioning product. I wouldn't be surprised if productivity under Mono/.NET was similarly problematic.

"Or did Microsoft just tick off the open source community and that made him decide to change?"

It's very unlikely Microsoft holds patents that threaten MySQL, PHP, Django, Rails or Clojure users. I would guess their patent-space overlaps quite nicely with Mono.

"F# on mono"

If Microsoft's empty threats scare you or your costumers, F# is not an option.

"I also found the comment about the .exe and .dll file extensions weird."

It _is_ weird. Only Windows uses such an odd convention. I think VMS used something like it. OS/2 too, but it is every bit as dead as we joke BSD is (it is not - I use it - calm down, *BSD people).

"Whatever the criteria, you have to establish them and the stick to them", "Sounded more like somebody just chasing whatever was trendy at the time"

Criteria can change. Rails and Django may be "trendy", but that "trendiness" happened because those who use them can deliver applications very quickly, faster than, say, JSF or ASP.NET MVC - It's derived from real-world results. "ability to easily find programmers" is nice, but if you can't train programmers in a language to make them functional in a week, you are probably training the wrong ones.

stefano• 17 years ago

  "Although I was unable to use LISP in any production code"

Does he refer to LISP 1.5?

lispm3• 17 years ago

If I need to run my programming language to run on top of the infrastructure of another program language to use its services, the designers made something wrong. Today larger applications are based on layers communicating with each other over all kinds of ways. Deeply embedding is just one way.

I also think that developers should do more than read books to evaluate a technology. Reading Lisp books is surely not sufficient - eventually the author now was able to use a Lisp dialect and not only read about it. The author is also mostly guessing that 'Clojure has all the benefits of LISP' without having used other Lisps.

Zak2• 17 years ago

I've used other Lisps to write production code, and I'll say that Clojure has all the benefits of the Lisp family. Certainly, specific other Lisps have their own advantages. I miss Common Lisp's method combination whenever I use any other language.

lispm3• 17 years ago

can Clojure now save images?

does it have CLOS? I thought a huge different to many Lisp dialects is that Clojure is not especially object-oriented. In contrast to most CL implementations (and other Lisp dialects like ISLisp, many Scheme implementations, ...), which are very object-oriented - using many CLOS-based libraries.

can it compile to C?

can I use it without the JVM?

does it start up in less than ten ms?

programmable reader?

more powerful exception handling for interactive software?

tail calls?

etc. etc.

I'm not saying that you need all that, but saying that Clojure has all that a typical CL implementation or what some of the more advanced Scheme implementation offer would surprise me...

From C# on Mono, to Clojure on the JVM

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