5 ms·

This illustrates the power & the problem of Common Lisp: the power is that it really is easy to add channels (and pretty much every other feature) to the langua

by wtbob 10y ago

This illustrates the power & the problem of Common Lisp: the power is that it really is easy to add channels (and pretty much every other feature) to the language yourself; the problem is that it's generally easier to write your own code to do this than to use (or fix …) someone else's. I've experienced exactly this: I too looked at ChanL. In my case it had a bug for one of my use cases, and it was honestly easier to roll my own channels (with, of course, their own bugs) than to understand & fix ChanL's bug. The problem is that this leads to a proliferation of different libraries, all doing similar things. The power is that one really can write just about anything, and it will work well enough for your use case.

codr4life 10y ago
What you're saying is really that it's too powerful for it's own good. And I agree. But what's good for Lisp isn't necessarily good for me, I prefer more power to one size fits all libraries. I think it comes down to experience in the end; the more you have, the more unwilling you are to give it up.
- reikonomusha 10y ago
  I disagree about it being "too powerful for its own good". If it was, we would have a magnificently efficient and useful library come out of this that brings Go- or Erlang-style programming to Lisp. But alas, this code does not. A lot of hardcore Lisp aficionados do the equivalent of a mathematician writing a "sketch of a proof" and saying "left as an exercise", without ever writing the details of the proof. It's occasionally aggravating when you pull in a library and discover that this is the case. To be clear, there are many Lisp folks do not do this. Some go the full mile and implement something completely and robustly. Edi Weitz has been the canonical example in the community.
  - codr4life 10y ago
    Completely, what is that? Doesn't that depend on context (as in problem being solved)? Simple is often faster, and these are pretty fast without even trying. There is plenty of room for simple, fast enough code. Owning code you understand is an advantage.
    - rtpg 10y ago
      Completeness means being as performant as possible on all the possible axes. You might want simplicity, but users also want performance. So a complete solution will be performant, but simple. You have one use case, but other users have others. A complete solution will work in as many use cases as possible given its constraints. Scala's parser combinators are a good example of a complete solution. It offers the "elegant" solution of parser combinators. But it also offers an implementation of this using things like Packrat parsing that are extremely efficient. The non-complete example of this is someone who writes a parser combinator library that is simple, but simply not performant for real world use. For example, you might write a simple version in Python, but not properly apply TCO and so your parser can't handle deeply nested structures because of a stack overflow. --- With regards to owning code, I remember hearing that it took 9 years of the initial publication of quicksort for there to be a bugfree implementation of it. Even easy things can be tricky.
    - jonathanstrange 10y ago
      Completely, what is that? Well, comprehensive unit tests for a start...
      - codr4life 10y ago
        What's comprehensive? Doesn't that too depend on context? I'm with Kent Beck on tests. I'll test as much as I have to too move forward with confidence. In the end, my goal is to write working code, not tests.
  - TeMPOraL 10y ago
    > A lot of hardcore Lisp aficionados do the equivalent of a mathematician writing a "sketch of a proof" and saying "left as an exercise", without ever writing the details of the proof. It's occasionally aggravating when you pull in a library and discover that this is the case. That's exactly "too powerful for its own good". It's so easy to write a half-assed sketch of a library that nevertheless gives you some new powerful feature, that some people end there, and publish the sketch that was enough for their use case.
- wtbob 10y ago
  I guess I should have mentioned that Lisp is my language of choice. I like the ease with which I can implement anything. But it does have a cost: everyone else implements everything himself, too. I actually think Quicklisp has helped. It's even easier to do (ql:quickload "foo-lib") than it is to write my own foo library.
  - nickik 10y ago
    Everybody can do that stuff in Clojure too, and it does not suffer from the same thing CL does. It seems to me that it is a culture/ecosystem problem more then anything else.
reikonomusha 10y ago
As you sort of imply, it doesn't help that each implementation is half-baked, incomplete, and unmaintained after 16 months. I've seen similar libraries that do the following, for example: * Serialization and deserialization * Promises * Generators * CPS Somehow none of these "100 line wonders" make it into idiomatic usage, despite their purported utility. These channels as presented don't solve many problems well. They will be very slow and contentious, they will be expensive to make, and they will not guard against memory ownership issues because you're just passing pointers to objects around, which message passing is supposed to solve. But, it'll become another library on Quicklisp that 3 people use and that people's applications will inadvertently depend on. Lisp is a fantastic language for many things, including a plethora of production applications, but it being a local optimum for exploratory programming means we get lots of very incomplete, scratch-an-itch code that is pawned off as a library intended for mass consumption. In fact, the author links to his GitHub repository, where you find exactly this random assortment of disparate utilities. If I had my way, the rhetoric of this post would be closer to a pedagogical exposition of channels, how they're used, what their benefits are, a proof-of-concept implementation, and a non-trivial example application. I would vehemently stay away from having the thesis be anything about Lisp or the ease of implementing small POCs in Lisp.
- codr4life 10y ago
  This implementation is yours to maintain, that's why it's simple enough to make that possible. There is plenty of room for simple. They allow building networks of cooperating threads, which is the purpose. Erlang isolates, Go doesn't, in the end I like the choice.
  - reikonomusha 10y ago
    Copy-pastable blog post code is the antithesis of good software engineering practices. DRY, encapsulation, reusability, broadly applicable abstractions, and so on should ideally be heralded as the thing to strive for.
    - codr4life 10y ago
deleted 10y ago
[deleted]
dfox 10y ago
In this case particular case, what is being shown is that channels in itself are pretty simple concept, especially when done on top of language with preemptive multithreading. Same thing can be implemented in essentially any imperative language with necessary primitives by code that looks more or less exactly same.
- codr4life 10y ago
  C with pthreads won't look the same, I know because I've tried hard. Java most definitely won't. Which languages are we talking about here anyway?
junke 10y ago
> The problem is that this leads to a proliferation of different libraries, all doing similar things. This is not "left-pad" either. I'd say you have the same problems in C or C++, where people are reluctant to depend on libraries they don't control or appear to be bloated (boost, etc.). As far as Lisp is concerned, this post talks about the problem more directly: http://fare.livejournal.com/169346.html http://fare.livejournal.com/169346.html
teddyh 10y ago
This is known as the “Lisp Curse”: http://www.winestockwebdesign.com/Essays/Lisp_Curse.html http://www.winestockwebdesign.com/Essays/Lisp_Curse.html

by wtbob 10y ago

codr4life 10y ago

What you're saying is really that it's too powerful for it's own good. And I agree. But what's good for Lisp isn't necessarily good for me, I prefer more power to one size fits all libraries. I think it comes down to experience in the end; the more you have, the more unwilling you are to give it up.

reikonomusha 10y ago
I disagree about it being "too powerful for its own good". If it was, we would have a magnificently efficient and useful library come out of this that brings Go- or Erlang-style programming to Lisp. But alas, this code does not. A lot of hardcore Lisp aficionados do the equivalent of a mathematician writing a "sketch of a proof" and saying "left as an exercise", without ever writing the details of the proof. It's occasionally aggravating when you pull in a library and discover that this is the case. To be clear, there are many Lisp folks do not do this. Some go the full mile and implement something completely and robustly. Edi Weitz has been the canonical example in the community.
- codr4life 10y ago
  Completely, what is that? Doesn't that depend on context (as in problem being solved)? Simple is often faster, and these are pretty fast without even trying. There is plenty of room for simple, fast enough code. Owning code you understand is an advantage.
  - rtpg 10y ago
    Completeness means being as performant as possible on all the possible axes. You might want simplicity, but users also want performance. So a complete solution will be performant, but simple. You have one use case, but other users have others. A complete solution will work in as many use cases as possible given its constraints. Scala's parser combinators are a good example of a complete solution. It offers the "elegant" solution of parser combinators. But it also offers an implementation of this using things like Packrat parsing that are extremely efficient. The non-complete example of this is someone who writes a parser combinator library that is simple, but simply not performant for real world use. For example, you might write a simple version in Python, but not properly apply TCO and so your parser can't handle deeply nested structures because of a stack overflow. --- With regards to owning code, I remember hearing that it took 9 years of the initial publication of quicksort for there to be a bugfree implementation of it. Even easy things can be tricky.
  - jonathanstrange 10y ago
    Completely, what is that? Well, comprehensive unit tests for a start...
    - codr4life 10y ago
      What's comprehensive? Doesn't that too depend on context? I'm with Kent Beck on tests. I'll test as much as I have to too move forward with confidence. In the end, my goal is to write working code, not tests.
- TeMPOraL 10y ago
  > A lot of hardcore Lisp aficionados do the equivalent of a mathematician writing a "sketch of a proof" and saying "left as an exercise", without ever writing the details of the proof. It's occasionally aggravating when you pull in a library and discover that this is the case. That's exactly "too powerful for its own good". It's so easy to write a half-assed sketch of a library that nevertheless gives you some new powerful feature, that some people end there, and publish the sketch that was enough for their use case.
wtbob 10y ago
I guess I should have mentioned that Lisp is my language of choice. I like the ease with which I can implement anything. But it does have a cost: everyone else implements everything himself, too. I actually think Quicklisp has helped. It's even easier to do (ql:quickload "foo-lib") than it is to write my own foo library.
- nickik 10y ago
  Everybody can do that stuff in Clojure too, and it does not suffer from the same thing CL does. It seems to me that it is a culture/ecosystem problem more then anything else.

reikonomusha 10y ago

As you sort of imply, it doesn't help that each implementation is half-baked, incomplete, and unmaintained after 16 months. I've seen similar libraries that do the following, for example: * Serialization and deserialization * Promises * Generators * CPS Somehow none of these "100 line wonders" make it into idiomatic usage, despite their purported utility. These channels as presented don't solve many problems well. They will be very slow and contentious, they will be expensive to make, and they will not guard against memory ownership issues because you're just passing pointers to objects around, which message passing is supposed to solve. But, it'll become another library on Quicklisp that 3 people use and that people's applications will inadvertently depend on. Lisp is a fantastic language for many things, including a plethora of production applications, but it being a local optimum for exploratory programming means we get lots of very incomplete, scratch-an-itch code that is pawned off as a library intended for mass consumption. In fact, the author links to his GitHub repository, where you find exactly this random assortment of disparate utilities. If I had my way, the rhetoric of this post would be closer to a pedagogical exposition of channels, how they're used, what their benefits are, a proof-of-concept implementation, and a non-trivial example application. I would vehemently stay away from having the thesis be anything about Lisp or the ease of implementing small POCs in Lisp.

codr4life 10y ago
This implementation is yours to maintain, that's why it's simple enough to make that possible. There is plenty of room for simple. They allow building networks of cooperating threads, which is the purpose. Erlang isolates, Go doesn't, in the end I like the choice.
- reikonomusha 10y ago
  Copy-pastable blog post code is the antithesis of good software engineering practices. DRY, encapsulation, reusability, broadly applicable abstractions, and so on should ideally be heralded as the thing to strive for.
  - codr4life 10y ago

deleted 10y ago

[deleted]

dfox 10y ago

In this case particular case, what is being shown is that channels in itself are pretty simple concept, especially when done on top of language with preemptive multithreading. Same thing can be implemented in essentially any imperative language with necessary primitives by code that looks more or less exactly same.

codr4life 10y ago
C with pthreads won't look the same, I know because I've tried hard. Java most definitely won't. Which languages are we talking about here anyway?

junke 10y ago

> The problem is that this leads to a proliferation of different libraries, all doing similar things. This is not "left-pad" either. I'd say you have the same problems in C or C++, where people are reluctant to depend on libraries they don't control or appear to be bloated (boost, etc.). As far as Lisp is concerned, this post talks about the problem more directly: http://fare.livejournal.com/169346.html http://fare.livejournal.com/169346.html

teddyh 10y ago

This is known as the “Lisp Curse”: http://www.winestockwebdesign.com/Essays/Lisp_Curse.html http://www.winestockwebdesign.com/Essays/Lisp_Curse.html