4 ms·

Ants: locks vs stm

69 points by silkodyssey 17y ago

itistoday 17y ago
I haven't seen a smackdown like that in a while... but that was just too easy, the OP had no clue what he was dealing with. Had he watched the Clojure concurrency video in which Rich extensively discusses the ant colony simulation and its purpose, he might not have made that mistake: http://blip.tv/file/812787 http://blip.tv/file/812787
- tc 17y ago
  Pascal Costanza (the OP) is a smart guy. He's behind the ContextL and AspectL frameworks, and he just published an interesting paper on implementing hygienic macros within an unhygienic macro system [1]. But in this instance, it seems he clearly missed the point of the Ants exercise. [1] http://p-cos.net/documents/hygiene.pdf http://p-cos.net/documents/hygiene.pdf
diN0bot 17y ago
full thread is somewhat more interesting than one guy's bitchy smackdown. http://groups.google.com/group/comp.lang.lisp/browse_thread/thread/1d014c846acaadc8/a86c91091ae16970 http://groups.google.com/group/comp.lang.lisp/browse_thread/...
- scott_s 17y ago
  It might be worth noting that "one guy" is the designer and implementer of Clojure.
- deleted 17y ago
  [deleted]
- rbancroft 17y ago
  um, no it isn't. And that one guy happens to be the guy who invented clojure. Rich Hickey does often seem a bit testy at times, but I think it's because he is a bit of a visionary and it is tiring always having to drag along people that don't quite get it.
  - icey 17y ago
    If you follow CLL, Rich and Pascal have had a back and forth on the newsgroup on more than this occasion.
    - slpsys 17y ago
      That actually makes a lot of sense, in context; I was wondering why/how Rich had enough time to pore over some random guy's implementation of ants, not knowing much about Pascal (until this HN thread). I think if people ignorant to his own accomplishments, it's because many F/OSS project mailing lists or IRC channels see messages from someone new to the project claiming a more naïve version of Pascal's email every few months (or weeks).
utx00 17y ago
talk about loop abuse: (flet ((make-random-move (rankf) (loop for place in places for rank = (funcall rankf place) collect (cons place rank) into ranks sum rank into ranks-total finally (loop with r = (if (zerop ranks-total) -1 (random ranks-total)) for (place . rank) in (shuffle ranks) sum rank into current-ranks-total when (< r current-ranks-total) do (cond ((and (eq place ahead) (move ant))) ((eq place ahead-left) (turn ant -1)) ((eq place ahead-right) (turn ant +1))))))) (if (ant-food ant)
- sbt 17y ago
  Yeah, this piece illustrates why Python is such a success and Lisp is not. Lambda may be the ultimate imperative, but certainly not the most convenient in many cases.
  - itistoday 17y ago
    You can write bad Python code too. Lisp is no longer one language, there are many Lisp variants that don't have CL's looping construct.
    - calpaterson 17y ago
      Lisp hasn't been "one language" for decades, and, by number, most lisp variants do not include the loop macro. It's just a popular dialect that does.
  - tc 17y ago
    You're not serious? The loop macro is the most Pythonic aspect of CL (c.f. list comprehensions). Your trouble handling that loop has nothing to do with lambdas.
gruseom 17y ago
I don't know anything about this and the flame/troll aspect of the thread makes me not want to. I was kind of hoping that a new Lisp on a new platform might have a chance at a fresh start clear of all that stuff. I did notice one thing, though. Assuming that what Rich Hickey's saying is true, it would be better to point to something visible that the demo does that the knockoff can't do. If it's possible to appear to reproduce a demo without doing the hard parts, then maybe the demo wasn't actually demonstrating the hard parts. In that case a better demo would be a good idea. Such things can be hard to come by, though, as demos tend to be relatively simple and thus knockoffable.
- deleted 17y ago
  [deleted]
- arohner 17y ago
  This locks vs. STM debate is a lot like the old malloc vs. GC debates. "Look at my fancy new Java code. I just do foo = new Foo(); and everything is taken care of" and then a C++ guy responds with "so? I can do foo = new Foo(); delete foo; That's only one more line than your fancy GC system. My version is also faster because it doesn't waste time on GC". Locks vs. STM will play out about the same way. It's hard to demonstrate all the things you don't have to care about with GC. Making a good demo that shows you don't need to worry about memory leaks, double freeing, memory corruption, etc is hard. The same is true of making a good demo for STM that illustrates all of the problems you don't have to worry about compared to locks. I think the ants demo is a good idea technically. Now it just needs a set of "rules", similar to what Rich just posted.
  - gruseom 17y ago
    I like your analogy. It may be that there isn't a program that's both complex enough to make the problem visible and small enough to count as a demo. In that case, it might be better to call it a sample. If it were my demo I'd focus on making the value visible. For example, if the value is correctness, then make it obvious when the state becomes incorrect. An incorrect program ought to hit this if it runs long enough.
  - 17y ago

69 points by silkodyssey 17y ago

I haven't seen a smackdown like that in a while... but that was just too easy, the OP had no clue what he was dealing with. Had he watched the Clojure concurrency video in which Rich extensively discusses the ant colony simulation and its purpose, he might not have made that mistake: http://blip.tv/file/812787 http://blip.tv/file/812787

tc 17y ago
Pascal Costanza (the OP) is a smart guy. He's behind the ContextL and AspectL frameworks, and he just published an interesting paper on implementing hygienic macros within an unhygienic macro system [1]. But in this instance, it seems he clearly missed the point of the Ants exercise. [1] http://p-cos.net/documents/hygiene.pdf http://p-cos.net/documents/hygiene.pdf

diN0bot 17y ago

full thread is somewhat more interesting than one guy's bitchy smackdown. http://groups.google.com/group/comp.lang.lisp/browse_thread/thread/1d014c846acaadc8/a86c91091ae16970 http://groups.google.com/group/comp.lang.lisp/browse_thread/...

scott_s 17y ago
It might be worth noting that "one guy" is the designer and implementer of Clojure.
deleted 17y ago
[deleted]
rbancroft 17y ago
um, no it isn't. And that one guy happens to be the guy who invented clojure. Rich Hickey does often seem a bit testy at times, but I think it's because he is a bit of a visionary and it is tiring always having to drag along people that don't quite get it.
- icey 17y ago
  If you follow CLL, Rich and Pascal have had a back and forth on the newsgroup on more than this occasion.
  - slpsys 17y ago
    That actually makes a lot of sense, in context; I was wondering why/how Rich had enough time to pore over some random guy's implementation of ants, not knowing much about Pascal (until this HN thread). I think if people ignorant to his own accomplishments, it's because many F/OSS project mailing lists or IRC channels see messages from someone new to the project claiming a more naïve version of Pascal's email every few months (or weeks).

utx00 17y ago

talk about loop abuse: (flet ((make-random-move (rankf) (loop for place in places for rank = (funcall rankf place) collect (cons place rank) into ranks sum rank into ranks-total finally (loop with r = (if (zerop ranks-total) -1 (random ranks-total)) for (place . rank) in (shuffle ranks) sum rank into current-ranks-total when (< r current-ranks-total) do (cond ((and (eq place ahead) (move ant))) ((eq place ahead-left) (turn ant -1)) ((eq place ahead-right) (turn ant +1))))))) (if (ant-food ant)

sbt 17y ago
Yeah, this piece illustrates why Python is such a success and Lisp is not. Lambda may be the ultimate imperative, but certainly not the most convenient in many cases.
- itistoday 17y ago
  You can write bad Python code too. Lisp is no longer one language, there are many Lisp variants that don't have CL's looping construct.
  - calpaterson 17y ago
    Lisp hasn't been "one language" for decades, and, by number, most lisp variants do not include the loop macro. It's just a popular dialect that does.
- tc 17y ago
  You're not serious? The loop macro is the most Pythonic aspect of CL (c.f. list comprehensions). Your trouble handling that loop has nothing to do with lambdas.

gruseom 17y ago

I don't know anything about this and the flame/troll aspect of the thread makes me not want to. I was kind of hoping that a new Lisp on a new platform might have a chance at a fresh start clear of all that stuff. I did notice one thing, though. Assuming that what Rich Hickey's saying is true, it would be better to point to something visible that the demo does that the knockoff can't do. If it's possible to appear to reproduce a demo without doing the hard parts, then maybe the demo wasn't actually demonstrating the hard parts. In that case a better demo would be a good idea. Such things can be hard to come by, though, as demos tend to be relatively simple and thus knockoffable.

deleted 17y ago
[deleted]
arohner 17y ago
This locks vs. STM debate is a lot like the old malloc vs. GC debates. "Look at my fancy new Java code. I just do foo = new Foo(); and everything is taken care of" and then a C++ guy responds with "so? I can do foo = new Foo(); delete foo; That's only one more line than your fancy GC system. My version is also faster because it doesn't waste time on GC". Locks vs. STM will play out about the same way. It's hard to demonstrate all the things you don't have to care about with GC. Making a good demo that shows you don't need to worry about memory leaks, double freeing, memory corruption, etc is hard. The same is true of making a good demo for STM that illustrates all of the problems you don't have to worry about compared to locks. I think the ants demo is a good idea technically. Now it just needs a set of "rules", similar to what Rich just posted.
- gruseom 17y ago
  I like your analogy. It may be that there isn't a program that's both complex enough to make the problem visible and small enough to count as a demo. In that case, it might be better to call it a sample. If it were my demo I'd focus on making the value visible. For example, if the value is correctness, then make it obvious when the state becomes incorrect. An incorrect program ought to hit this if it runs long enough.
- 17y ago