Re: clojure.java.jdbc: suggestion to name mapping
You can wrap your code in (entities ...) and/or (identifiers ...) and it will apply to all the java.jdbc calls inside. Clojure/core have specifically said they don't want *dynamic-vars* in contrib libraries. We have thousands of lines of java.jdbc code at work and name mapping hasn't been an issue - it's easy enough to wrap calls where name mapping is really needed - and mostly it isn't. Can you explain your use case where you have a problem with the current setup? Sean On Mon, Aug 26, 2013 at 8:23 PM, Alice dofflt...@gmail.com wrote: Then, how about making them global so that they can be altered? I know global parameters are ugly, but having to specify them every time is really a pain. On Tuesday, August 27, 2013 2:32:20 AM UTC+9, Sean Corfield wrote: The db-spec is not used by the DSL. Name mapping is a function of the DSL, in general. This request has come up in the past and it just isn't practical since the db-spec is completely independent of the DSL. On Mon, Aug 26, 2013 at 6:06 AM, Alice doff...@gmail.com wrote: It would be convenient if I can specify the default entities and identifiers functions in a database spec. I usually want those mappings to be applied all the time. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clo...@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+u...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+u...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- Sean A Corfield -- (904) 302-SEAN An Architect's View -- http://corfield.org/ World Singles, LLC. -- http://worldsingles.com/ Perfection is the enemy of the good. -- Gustave Flaubert, French realist novelist (1821-1880) -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- Sean A Corfield -- (904) 302-SEAN An Architect's View -- http://corfield.org/ World Singles, LLC. -- http://worldsingles.com/ Perfection is the enemy of the good. -- Gustave Flaubert, French realist novelist (1821-1880) -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: too circular?
thx 2013/8/26 Marshall Bockrath-Vandegrift llas...@gmail.com Dennis Haupt d.haup...@gmail.com writes: (defn fib-n [n] (let [fib (fn [a b] (cons a (lazy-seq (fib b (+ b a)] (take n (fib 1 1 can't i do a recursion here? how can i achieve this without doing an outer defn? You just need to give the anonymous function a name it can use to refer to itself for (non-tail) recursion: (defn fib-n [n] (let [fib (fn fib [a b] (cons a (lazy-seq (fib b (+ b a)] (take n (fib 1 1 -Marshall -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: [ANN] nativot 0.1.0 (leiningen plugin) public beta
Oh right, there is the license hassle. I am going to contact JDotSoft and see if it is possible to make it all more friendly! вторник, 27 августа 2013 г., 4:26:42 UTC+4 пользователь Mikera написал: JarClassLoader looks cool Aren't there some pretty severe licensing restrictions though? Looks like it is GPLv3 or commercial license only from the website, which rules it out of most EPL projects I think On Tuesday, 27 August 2013 03:50:10 UTC+8, Alex Fowler wrote: hi, nativot is a leiningen plugin that is intended to deliver clojurians from the burden of classpath hells of any flavour. highlights: 1) built upon lein uberjar and jdotsoft jarclassloader 2) makes it possible to deploy clojure application that depend upon any jar-files, native libraries, binary resources and other goodness 3) you can deploy your application as a single jar, as well as a single jar with externalized resources. more on this at http://www.jdotsoft.com/JarClassLoader.php 4) simple notes: 1) still in beta 2) requires active internet connection 3) due to some leiningen project management pecularities, requires some manual project.clj adjustment, see the description at clojars, or the description in the next post in this thread 4) creates additional source folders in your project 5) worships the just put that jar/native/binary nearby and it will be included approach instead of the traditional repeatability maven-induced one. USE WITH CARE. the plugin is not intended to replace the repeatability approach. actually they are better used together. clojars link: https://clojars.org/nativot disclaimer: this is my first plugin for leningen and i am new to clojure, so take it easy. and thanks to Zach Tellman for kind guidance! any success stories, failure stories, bug reports, ideas on improvement and such are welcomed. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
It's a real problem for me too, I also wonder what was the intention behind this. I guess there could be a very good reason for this special treatement of nils, but I haven't seen it yet. I would love to hear about this from people involved in core.async development. On Friday, August 16, 2013 4:44:48 AM UTC+2, Mikera wrote: Hi all, I'm experimenting with core.async. Most of it is exceptionally good, but bit I'm finding it *very* inconvenient that nil can't be sent over channels. In particular, you can't pipe arbitrary Clojure sequences through channels (since sequences can contain nils). I see this as a pretty big design flaw given the ubiquity of sequences in Clojure code - it appears to imply that you can't easily compose channels with generic sequence-handling code without some pretty ugly special-case handling. Am I missing something? Is this a real problem for others too? If it is a design flaw, can it be fixed before the API gets locked down? -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[ANN] migae-examples: Clojure, servlets, Google App Engine
Hi list, migae-examples https://github.com/greynolds/migae-examples is a series of examples demonstrating the use of Clojure to implement servlets for both standard servlet containers and Google App Engine. The purpose is not so much to explain how to code as to show what's going on behind the scenes with gen-class, the Clojure runtime, and servlet containers. The examples start with a minimal Java implementation and progress through use of Ring and Compojure, to use of GAE. (The GAE stuff is very minimal at the moment; a Clojure wrapper for GAE services is under development). Along the way they show how to use a Servlet Filter to get interactive repl-like behavior out of a servlet container. The focus is on understanding what happens at compile time and runtime. The approach is a little different from that of Ring. Ring uses an embedded Jetty server to run web apps. I wanted support for multiple servlets, filters, use of web.xml, etc. and use of standalone servers. So these examples are a sort of record of how to figure out how to do that. They might be useful even for people who have been using Ring, if they have not looked at how it all works under the covers. The code, with a bunch of explanatory text, is at https://github.com/greynolds/migae-examples I also came up with a somewhat perverse hack that supports interactive development using the GAE dev_appserver. It's a little twisted but it works. See example gae2. Feedback would be welcome, especially from people who know the gory details of Clojure. I made the examples as I was exploring the workings of servlets and clojure, so some of what I say is based on knowledge but some is based on inference, so there may be some errors of explanation. Cheers, Gregg -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
stringify an interned function
Hello, I am new to clojure, and I am trying to define a function that turns a function-name into a string, but I am stuck. Here is what I tried: user (defn some-func [] true) I am looking for a function stringify that would do the following user (stringify some-func) some-func I can do it with var as long it is not wrapped in a defn-form: user (second (clojure.string/split (str (var some-func)) #/)) However, if I try to put it into a defn, I get an error: user (defn stringify [func] (second (clojure.string/split (str (var func)) #/))) CompilerException java.lang.RuntimeException: Unable to resolve var: func in this context, compiling:(/tmp/form-init6959523461952831160.clj:2:37) What am I missing here? Thanks in advance... -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: stringify an interned function
On 27/08/13 10:39, Erebus Mons wrote: I am looking for a function stringify that would do the following user (stringify some-func) some-func (- #'some-func meta :name str) (defn stringify [func] (- func var meta :name str)) Jim -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: stringify an interned function
On 27/08/13 13:13, Jim wrote: (defn stringify [func] (- func var meta :name str)) I'm sorry this won't work...try this: (defn stringify [fvar] (- fvar meta :name str)) and pass in the var object like this: (stringify (var some-func)) OR (stringify #'some-func) btw, you will only get the name not the namespace it belongs in... Jim -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: stringify an interned function
or convert it to a macro and it should work as you hoped :) (defmacro stringify [f] `(- ~f var meta :name str)) HTH, Jim On 27/08/13 13:26, Jim wrote: On 27/08/13 13:13, Jim wrote: (defn stringify [func] (- func var meta :name str)) I'm sorry this won't work...try this: (defn stringify [fvar] (- fvar meta :name str)) and pass in the var object like this: (stringify (var some-func)) OR (stringify #'some-func) btw, you will only get the name not the namespace it belongs in... Jim -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
The reason for not allowing nils isn't a complex one, and basically boils down to the following: a) to avoid race conditions, we need a single value to signal the channel is closed. As mentioned, nil is the obvious choice for this as it matches lazy seqs and fits well with the rest of clojure: (when-let [v (! c)] (process v)) If we chose a different value, this becomes much more ugly: (let [v (! c)] (when-not (= v :async/closed) (process v))) b) I question if there are any valid uses for putting nil in a channel. With all due respect to all who have written here, thus far, every complaint about nils and channels boils down to a conversion from seqs to channels. This is the wrong way to look at the problem. Channels are co-ordination primitives not data structures. Simply because a lazy seq looks like a channel, doesn't mean that they should be treated as such. In all the core.async code I've written I've never had to put a nil in a channel, so I'm left with the uncomfortable conclusion that most complaints on this subject are contrived. I could be wrong, but I just haven't seen a valid use case yet. This all being said, there really isn't a technical reason to not allow nils, it just simplifies much of the design and that probably translates to better performance. So the restriction could be lifted if a rock solid reason could be found, but as of yet, I haven't seen it. Timothy Baldridge On Tue, Aug 27, 2013 at 2:12 AM, Max Penet m...@qbits.cc wrote: It's a real problem for me too, I also wonder what was the intention behind this. I guess there could be a very good reason for this special treatement of nils, but I haven't seen it yet. I would love to hear about this from people involved in core.async development. On Friday, August 16, 2013 4:44:48 AM UTC+2, Mikera wrote: Hi all, I'm experimenting with core.async. Most of it is exceptionally good, but bit I'm finding it *very* inconvenient that nil can't be sent over channels. In particular, you can't pipe arbitrary Clojure sequences through channels (since sequences can contain nils). I see this as a pretty big design flaw given the ubiquity of sequences in Clojure code - it appears to imply that you can't easily compose channels with generic sequence-handling code without some pretty ugly special-case handling. Am I missing something? Is this a real problem for others too? If it is a design flaw, can it be fixed before the API gets locked down? -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- “One of the main causes of the fall of the Roman Empire was that–lacking zero–they had no way to indicate successful termination of their C programs.” (Robert Firth) -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: stringify an interned function
Jim wrote: or convert it to a macro and it should work as you hoped :) (defmacro stringify [f] `(- ~f var meta :name str)) HTH, Cool! That is exactly what I was looking for! Best, EM Jim On 27/08/13 13:26, Jim wrote: On 27/08/13 13:13, Jim wrote: (defn stringify [func] (- func var meta :name str)) I'm sorry this won't work...try this: (defn stringify [fvar] (- fvar meta :name str)) and pass in the var object like this: (stringify (var some-func)) OR (stringify #'some-func) btw, you will only get the name not the namespace it belongs in... Jim -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
profiler?
What are you all using these days? I've been using YourKit and I'm fairly happy with it. Just making sure I'm not missing out on some new hotness. Cheers, Jay -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: profiler?
yep, yourkit 2013/8/27 Jay Fields j...@jayfields.com What are you all using these days? I've been using YourKit and I'm fairly happy with it. Just making sure I'm not missing out on some new hotness. Cheers, Jay -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: profiler?
On 27/08/13 15:06, Jay Fields wrote: What are you all using these days? I've been using YourKit and I'm fairly happy with it. Just making sure I'm not missing out on some new hotness. Cheers, Jay I used to use JVisualVM and Jconsole but for some reason both stopped working when I updated to Java7 u21 or something... Jim -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: profiler?
On 8/27/13 8:06 AM, Jay Fields wrote: What are you all using these days? I've been using YourKit and I'm fairly happy with it. Just making sure I'm not missing out on some new hotness. Cheers, Jay YourKit plus VisualVM in some cases (I'm not as familiar w/YourKit and I really like the VisualGC plugin for VisualVM). For microbenchmarks I find criterium to be useful. -Ben -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
On 27 August 2013 20:45, Timothy Baldridge tbaldri...@gmail.com wrote: The reason for not allowing nils isn't a complex one, and basically boils down to the following: a) to avoid race conditions, we need a single value to signal the channel is closed. As mentioned, nil is the obvious choice for this as it matches lazy seqs and fits well with the rest of clojure: Agreed that you want a single sentinel value. It doesn't match lazy-seqs at all though: lazy seqs can contain nils just fine. There's a big difference between (next some-lazy-seq) [which could be nil, indicating an empty sequence] and the actual values in the seq [which could also be nil but don't indicate the end of the seq]. (when-let [v (! c)] (process v)) If we chose a different value, this becomes much more ugly: (let [v (! c)] (when-not (= v :async/closed) (process v))) This can be solved easily by providing a macro or some other predicate that knows how to check for the sentinel value correctly. e.g. (when-more [v (! c)] (process v)) b) I question if there are any valid uses for putting nil in a channel. With all due respect to all who have written here, thus far, every complaint about nils and channels boils down to a conversion from seqs to channels. This is the wrong way to look at the problem. Channels are co-ordination primitives not data structures. Simply because a lazy seq looks like a channel, doesn't mean that they should be treated as such. In all the core.async code I've written I've never had to put a nil in a channel, so I'm left with the uncomfortable conclusion that most complaints on this subject are contrived. I could be wrong, but I just haven't seen a valid use case yet. To me it's all about consistency with other Clojure constructs. You can safely put nils in sequences, vectors, lists, sets etc.. nil is a valid value just like anything else. So why can't you put them in a channel? Two use cases I have encountered that motivate this: a) what if you want to send a sequence through a channel? Since nil as a value represents the empty sequence, you have to put in some extra special case handling with the current core.async model. b) what if you want to write generic code to send all the values in an arbitrary collection through a channel? you would have to wrap/unwrap nils at either end to make this work currently. Both of these, I think, are reasonable and common enough use cases that it's worth supporting them elegantly rather than forcing users to implement their own nil-wrapping functionality. This all being said, there really isn't a technical reason to not allow nils, it just simplifies much of the design and that probably translates to better performance. So the restriction could be lifted if a rock solid reason could be found, but as of yet, I haven't seen it. I don't believe there is any noticeable performance difference between checking for nil and checking if a value is identical? to some sentinel value (which would presumably be static, final, immutable and hence very well optimised by the JVM). In addition, not allowing nils just means you have to do extra work to wrap/unwrap nils as a user - which is almost certainly a net loss on overall performance. Still, I think consistency is more significant than the performance argument in this case. Timothy Baldridge On Tue, Aug 27, 2013 at 2:12 AM, Max Penet m...@qbits.cc wrote: It's a real problem for me too, I also wonder what was the intention behind this. I guess there could be a very good reason for this special treatement of nils, but I haven't seen it yet. I would love to hear about this from people involved in core.async development. On Friday, August 16, 2013 4:44:48 AM UTC+2, Mikera wrote: Hi all, I'm experimenting with core.async. Most of it is exceptionally good, but bit I'm finding it *very* inconvenient that nil can't be sent over channels. In particular, you can't pipe arbitrary Clojure sequences through channels (since sequences can contain nils). I see this as a pretty big design flaw given the ubiquity of sequences in Clojure code - it appears to imply that you can't easily compose channels with generic sequence-handling code without some pretty ugly special-case handling. Am I missing something? Is this a real problem for others too? If it is a design flaw, can it be fixed before the API gets locked down? -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop
Re: core.async - handling nils
All your arguments come down to this: I have an arbitrary seq of things I want to send down a channel. It's exactly that concept I that I push against. Everything you've mentioned thus far is a data structure. Channels are not data structures they are concurrency management primitives, treat them as such and I doubt you'll ever have a need for nils in a channel. If we treat channels as ways of co-ordinating concurrent processes, then nil doesn't have a use case. In every use of channels I've had thus far, nil is better expressed as an empty collection, false, 0, :tick, or some other ground value. It's these Rx style programming methods that make people think they need this feature. Timothy On Tue, Aug 27, 2013 at 8:51 AM, Mike Anderson mike.r.anderson...@gmail.com wrote: On 27 August 2013 20:45, Timothy Baldridge tbaldri...@gmail.com wrote: The reason for not allowing nils isn't a complex one, and basically boils down to the following: a) to avoid race conditions, we need a single value to signal the channel is closed. As mentioned, nil is the obvious choice for this as it matches lazy seqs and fits well with the rest of clojure: Agreed that you want a single sentinel value. It doesn't match lazy-seqs at all though: lazy seqs can contain nils just fine. There's a big difference between (next some-lazy-seq) [which could be nil, indicating an empty sequence] and the actual values in the seq [which could also be nil but don't indicate the end of the seq]. (when-let [v (! c)] (process v)) If we chose a different value, this becomes much more ugly: (let [v (! c)] (when-not (= v :async/closed) (process v))) This can be solved easily by providing a macro or some other predicate that knows how to check for the sentinel value correctly. e.g. (when-more [v (! c)] (process v)) b) I question if there are any valid uses for putting nil in a channel. With all due respect to all who have written here, thus far, every complaint about nils and channels boils down to a conversion from seqs to channels. This is the wrong way to look at the problem. Channels are co-ordination primitives not data structures. Simply because a lazy seq looks like a channel, doesn't mean that they should be treated as such. In all the core.async code I've written I've never had to put a nil in a channel, so I'm left with the uncomfortable conclusion that most complaints on this subject are contrived. I could be wrong, but I just haven't seen a valid use case yet. To me it's all about consistency with other Clojure constructs. You can safely put nils in sequences, vectors, lists, sets etc.. nil is a valid value just like anything else. So why can't you put them in a channel? Two use cases I have encountered that motivate this: a) what if you want to send a sequence through a channel? Since nil as a value represents the empty sequence, you have to put in some extra special case handling with the current core.async model. b) what if you want to write generic code to send all the values in an arbitrary collection through a channel? you would have to wrap/unwrap nils at either end to make this work currently. Both of these, I think, are reasonable and common enough use cases that it's worth supporting them elegantly rather than forcing users to implement their own nil-wrapping functionality. This all being said, there really isn't a technical reason to not allow nils, it just simplifies much of the design and that probably translates to better performance. So the restriction could be lifted if a rock solid reason could be found, but as of yet, I haven't seen it. I don't believe there is any noticeable performance difference between checking for nil and checking if a value is identical? to some sentinel value (which would presumably be static, final, immutable and hence very well optimised by the JVM). In addition, not allowing nils just means you have to do extra work to wrap/unwrap nils as a user - which is almost certainly a net loss on overall performance. Still, I think consistency is more significant than the performance argument in this case. Timothy Baldridge On Tue, Aug 27, 2013 at 2:12 AM, Max Penet m...@qbits.cc wrote: It's a real problem for me too, I also wonder what was the intention behind this. I guess there could be a very good reason for this special treatement of nils, but I haven't seen it yet. I would love to hear about this from people involved in core.async development. On Friday, August 16, 2013 4:44:48 AM UTC+2, Mikera wrote: Hi all, I'm experimenting with core.async. Most of it is exceptionally good, but bit I'm finding it *very* inconvenient that nil can't be sent over channels. In particular, you can't pipe arbitrary Clojure sequences through channels (since sequences can contain nils). I see this as a pretty big design flaw given the ubiquity of sequences in Clojure code - it appears to imply
Re: core.async - handling nils
On Tue, Aug 27, 2013 at 10:51 AM, Mike Anderson mike.r.anderson...@gmail.com wrote: To me it's all about consistency with other Clojure constructs. You can safely put nils in sequences, vectors, lists, sets etc.. nil is a valid value just like anything else. So why can't you put them in a channel? Channels are *not* data structures nor are they a place to put something. a) what if you want to send a sequence through a channel? Since nil as a value represents the empty sequence, you have to put in some extra special case handling with the current core.async model. You're not going to put random sequences into channels. Channels are conduits for meaningful messages - some well considered coordination protocol. Both of these, I think, are reasonable and common enough use cases that it's worth supporting them elegantly rather than forcing users to implement their own nil-wrapping functionality. If you're putting arbitrary sequences into a channel and need to wrap nils, you probably need to redesign your coordination protocol. David -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
In every use of channels I've had thus far, nil is better expressed as an empty collection, false, 0, :tick, or some other ground value. I agree completely. But I'll note that you mention false being useful... If you're writing completely general operators, like map, which are *sometimes* quite useful, then you have no choice but to do something like if-recv or explicitly test against nil. It's these Rx style programming methods that make people think they need this feature. I built my little Rx with channels library (asyncx) without intention to use it directly, but because I wanted to learn how to work with channels. I rapidly learned that the techniques are a lot more different than they look. In particular, it's more difficult to write channel process combinators precisely because they are more powerful. However, in practice, each new reusable channel/process combinator yields more complexity than it tends to save. I'd rather intentionally choose strictly less powerful primitives where appropriate and enforce that with encapsulation. With that in mind, if I ever revisit asyncx, I'll probably define push sequences or streams in terms of protocols and deftypes. I'd use core.async to implement them, but only for the lowest level primitives. I'd provide ways to get in to or out of the stream subsystem for interop with channels, but the public interface would take IStream objects. On Tue, Aug 27, 2013 at 10:58 AM, Timothy Baldridge tbaldri...@gmail.comwrote: All your arguments come down to this: I have an arbitrary seq of things I want to send down a channel. It's exactly that concept I that I push against. Everything you've mentioned thus far is a data structure. Channels are not data structures they are concurrency management primitives, treat them as such and I doubt you'll ever have a need for nils in a channel. If we treat channels as ways of co-ordinating concurrent processes, then nil doesn't have a use case. In every use of channels I've had thus far, nil is better expressed as an empty collection, false, 0, :tick, or some other ground value. It's these Rx style programming methods that make people think they need this feature. Timothy On Tue, Aug 27, 2013 at 8:51 AM, Mike Anderson mike.r.anderson...@gmail.com wrote: On 27 August 2013 20:45, Timothy Baldridge tbaldri...@gmail.com wrote: The reason for not allowing nils isn't a complex one, and basically boils down to the following: a) to avoid race conditions, we need a single value to signal the channel is closed. As mentioned, nil is the obvious choice for this as it matches lazy seqs and fits well with the rest of clojure: Agreed that you want a single sentinel value. It doesn't match lazy-seqs at all though: lazy seqs can contain nils just fine. There's a big difference between (next some-lazy-seq) [which could be nil, indicating an empty sequence] and the actual values in the seq [which could also be nil but don't indicate the end of the seq]. (when-let [v (! c)] (process v)) If we chose a different value, this becomes much more ugly: (let [v (! c)] (when-not (= v :async/closed) (process v))) This can be solved easily by providing a macro or some other predicate that knows how to check for the sentinel value correctly. e.g. (when-more [v (! c)] (process v)) b) I question if there are any valid uses for putting nil in a channel. With all due respect to all who have written here, thus far, every complaint about nils and channels boils down to a conversion from seqs to channels. This is the wrong way to look at the problem. Channels are co-ordination primitives not data structures. Simply because a lazy seq looks like a channel, doesn't mean that they should be treated as such. In all the core.async code I've written I've never had to put a nil in a channel, so I'm left with the uncomfortable conclusion that most complaints on this subject are contrived. I could be wrong, but I just haven't seen a valid use case yet. To me it's all about consistency with other Clojure constructs. You can safely put nils in sequences, vectors, lists, sets etc.. nil is a valid value just like anything else. So why can't you put them in a channel? Two use cases I have encountered that motivate this: a) what if you want to send a sequence through a channel? Since nil as a value represents the empty sequence, you have to put in some extra special case handling with the current core.async model. b) what if you want to write generic code to send all the values in an arbitrary collection through a channel? you would have to wrap/unwrap nils at either end to make this work currently. Both of these, I think, are reasonable and common enough use cases that it's worth supporting them elegantly rather than forcing users to implement their own nil-wrapping functionality. This all being said, there really isn't a technical reason to not allow nils, it just
Re: core.async - handling nils
Right, the use of false is a special case. I'm thinking of a mouse event stream, may have a button channel that sends true or false based on the state of the mouse button. Even saying that though, I would probably opt for :clicked and :unclicked or somethig of that nature. Timothy On Tue, Aug 27, 2013 at 9:15 AM, Brandon Bloom brandon.d.bl...@gmail.comwrote: In every use of channels I've had thus far, nil is better expressed as an empty collection, false, 0, :tick, or some other ground value. I agree completely. But I'll note that you mention false being useful... If you're writing completely general operators, like map, which are *sometimes* quite useful, then you have no choice but to do something like if-recv or explicitly test against nil. It's these Rx style programming methods that make people think they need this feature. I built my little Rx with channels library (asyncx) without intention to use it directly, but because I wanted to learn how to work with channels. I rapidly learned that the techniques are a lot more different than they look. In particular, it's more difficult to write channel process combinators precisely because they are more powerful. However, in practice, each new reusable channel/process combinator yields more complexity than it tends to save. I'd rather intentionally choose strictly less powerful primitives where appropriate and enforce that with encapsulation. With that in mind, if I ever revisit asyncx, I'll probably define push sequences or streams in terms of protocols and deftypes. I'd use core.async to implement them, but only for the lowest level primitives. I'd provide ways to get in to or out of the stream subsystem for interop with channels, but the public interface would take IStream objects. On Tue, Aug 27, 2013 at 10:58 AM, Timothy Baldridge tbaldri...@gmail.comwrote: All your arguments come down to this: I have an arbitrary seq of things I want to send down a channel. It's exactly that concept I that I push against. Everything you've mentioned thus far is a data structure. Channels are not data structures they are concurrency management primitives, treat them as such and I doubt you'll ever have a need for nils in a channel. If we treat channels as ways of co-ordinating concurrent processes, then nil doesn't have a use case. In every use of channels I've had thus far, nil is better expressed as an empty collection, false, 0, :tick, or some other ground value. It's these Rx style programming methods that make people think they need this feature. Timothy On Tue, Aug 27, 2013 at 8:51 AM, Mike Anderson mike.r.anderson...@gmail.com wrote: On 27 August 2013 20:45, Timothy Baldridge tbaldri...@gmail.com wrote: The reason for not allowing nils isn't a complex one, and basically boils down to the following: a) to avoid race conditions, we need a single value to signal the channel is closed. As mentioned, nil is the obvious choice for this as it matches lazy seqs and fits well with the rest of clojure: Agreed that you want a single sentinel value. It doesn't match lazy-seqs at all though: lazy seqs can contain nils just fine. There's a big difference between (next some-lazy-seq) [which could be nil, indicating an empty sequence] and the actual values in the seq [which could also be nil but don't indicate the end of the seq]. (when-let [v (! c)] (process v)) If we chose a different value, this becomes much more ugly: (let [v (! c)] (when-not (= v :async/closed) (process v))) This can be solved easily by providing a macro or some other predicate that knows how to check for the sentinel value correctly. e.g. (when-more [v (! c)] (process v)) b) I question if there are any valid uses for putting nil in a channel. With all due respect to all who have written here, thus far, every complaint about nils and channels boils down to a conversion from seqs to channels. This is the wrong way to look at the problem. Channels are co-ordination primitives not data structures. Simply because a lazy seq looks like a channel, doesn't mean that they should be treated as such. In all the core.async code I've written I've never had to put a nil in a channel, so I'm left with the uncomfortable conclusion that most complaints on this subject are contrived. I could be wrong, but I just haven't seen a valid use case yet. To me it's all about consistency with other Clojure constructs. You can safely put nils in sequences, vectors, lists, sets etc.. nil is a valid value just like anything else. So why can't you put them in a channel? Two use cases I have encountered that motivate this: a) what if you want to send a sequence through a channel? Since nil as a value represents the empty sequence, you have to put in some extra special case handling with the current core.async model. b) what if you want to write generic code to send all the values in an arbitrary
Re: core.async - handling nils
+1 We built a distributed software sending/receiving *messages* based on different protocols. All our protocols wrap data in an envelope. The receiver can then decide how to handle the message based on the envelope. Obviously, nil makes a bad envelope. A nil message on a channel never had any significance to us four years ago and rethinking about it we reach the same conclusion today :) Luc P. On Tue, Aug 27, 2013 at 10:51 AM, Mike Anderson mike.r.anderson...@gmail.com wrote: To me it's all about consistency with other Clojure constructs. You can safely put nils in sequences, vectors, lists, sets etc.. nil is a valid value just like anything else. So why can't you put them in a channel? Channels are *not* data structures nor are they a place to put something. a) what if you want to send a sequence through a channel? Since nil as a value represents the empty sequence, you have to put in some extra special case handling with the current core.async model. You're not going to put random sequences into channels. Channels are conduits for meaningful messages - some well considered coordination protocol. Both of these, I think, are reasonable and common enough use cases that it's worth supporting them elegantly rather than forcing users to implement their own nil-wrapping functionality. If you're putting arbitrary sequences into a channel and need to wrap nils, you probably need to redesign your coordination protocol. David -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- Softaddictslprefonta...@softaddicts.ca sent by ibisMail from my ipad! -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Rxjava + Clojure Users
Hi. I'm writing to see if there's anyone out there using RxJava [1] from Clojure and to get their opinion on it's current, built-in support for non-Java languages. Just to recap, the current implementation knows about clojure.lang.IFn allowing functions to be passed directly to RxJava methods: (- my-observable (.map (fn [v] (Long/parseLong v))) (.reduce +)) RxJava will automatically convert these functions to the underlying rx.util.functions.FuncX interface and re-dispatch to the appropriate method. So, the question is: as a user of RxJava, how valuable is this feature? Do you just end up wrapping things anyway, so you could easily perform the same transformation in your wrapper? Would helper fns/macros be a sufficient alternative: (- my-observable (.map (rx/fn [v] (Long/parseLong v))) (.reduce (rx/fn* +))) There will be some changes in this area in the near future and we'd like to get a feel for if/how people are using RxJava from Clojure. Thanks! Dave [1] https://github.com/Netflix/RxJava -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
On Tue, Aug 27, 2013 at 7:51 AM, Mike Anderson mike.r.anderson...@gmail.com wrote: On 27 August 2013 20:45, Timothy Baldridge tbaldri...@gmail.com wrote: The reason for not allowing nils isn't a complex one, and basically boils down to the following: a) to avoid race conditions, we need a single value to signal the channel is closed. As mentioned, nil is the obvious choice for this as it matches lazy seqs and fits well with the rest of clojure: Agreed that you want a single sentinel value. It doesn't match lazy-seqs at all though: lazy seqs can contain nils just fine. There's a big difference between (next some-lazy-seq) [which could be nil, indicating an empty sequence] and the actual values in the seq [which could also be nil but don't indicate the end of the seq]. And the when-first macro correctly handles this! It's not just `(when-let [~x (first ~xs)] ~@body). when-first nicely hides away what would otherwise be much more ugly. -- Ben Wolfson Human kind has used its intelligence to vary the flavour of drinks, which may be sweet, aromatic, fermented or spirit-based. ... Family and social life also offer numerous other occasions to consume drinks for pleasure. [Larousse, Drink entry] -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Heroku app using core.async?
Hi, I just managed to use core.async for the need I described in my previous email and tried to push this to heroku, but git bitten: Could not find artifact core.async:core.async:jar:0.1.0-SNAPSHOT in clojars (https://clojars.org/repo/) Could not find artifact core.async:core.async:jar:0.1.0-SNAPSHOT in sonatype-oss-public (https://oss.sonatype.org/content/groups/public/) Am I guessing right that heroku prevents downloading libraries from external repositories listed in :repositories? Is anyone using core.async on heroku? Thanks! -- Bastien -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: Rxjava + Clojure Users
On 8/27/13 10:03 AM, Dave Ray wrote: Hi. I'm writing to see if there's anyone out there using RxJava [1] from Clojure and to get their opinion on it's current, built-in support for non-Java languages. Just to recap, the current implementation knows about clojure.lang.IFn allowing functions to be passed directly to RxJava methods: (- my-observable (.map (fn [v] (Long/parseLong v))) (.reduce +)) RxJava will automatically convert these functions to the underlying rx.util.functions.FuncX interface and re-dispatch to the appropriate method. So, the question is: as a user of RxJava, how valuable is this feature? Do you just end up wrapping things anyway, so you could easily perform the same transformation in your wrapper? Would helper fns/macros be a sufficient alternative: (- my-observable (.map (rx/fn [v] (Long/parseLong v))) (.reduce (rx/fn* +))) There will be some changes in this area in the near future and we'd like to get a feel for if/how people are using RxJava from Clojure. Thanks! Dave [1] https://github.com/Netflix/RxJava Hi Dave, We've been using RxJava from Clojure in production for a bit now but in a limited fashion. While I saw many places where I would want to wrap RxJava I ended up not and instead just used the built-in methods since they played nicely with clojure fns. How valuable is it? It has been nice for our limited use but I think for a larger project we would end up wrapping it anyways. (I would probably wrap the methods like .map, etc, so that they just take fns). So if it makes things easier for RxJava to drop the support I say drop it. I've been thinking that the clojure community could benefit from a clj-rx project that that would define protocols for all the Rx primitives and a consistent API which could be implemented in a number of ways but would all adhere to the Rx contract. RxJava and core.async being the two most obvious implementations but others could also wrap Rx js libs for use in ClojureScript if they needed to. I know your question is specifically about RxJava but if you are going down the route of wrapping it in a nice idiomatic clojure API it may be worth taking a step back and seeing if taking the protocol approach makes sense. I'd be interesting in collaborating on this if you decide to go down this route. On a related Rx/core.async note... At work we are now using core.async for many of the workflows where I would have otherwise reached for Rx (and vanilla java.util.cc). I've been finding that some tasks are much easier to think about using CSP and allow you to model certain processes in a clearer way. Other times I find myself reaching for the nice abstraction Rx brings and I usually end up implementing some of the functions on top of core.async (similar to what Brandon Bloom has done in his experimental lib). This is why thinking having a unified clj-rx API warrants further exploration. I'd love to hear other peoples thoughts on this as well. -Ben -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
As long as we don't go full Haskell mode: data Message a = Value a | Done On Tue, Aug 27, 2013 at 11:20 AM, Timothy Baldridge tbaldri...@gmail.comwrote: Right, the use of false is a special case. I'm thinking of a mouse event stream, may have a button channel that sends true or false based on the state of the mouse button. Even saying that though, I would probably opt for :clicked and :unclicked or somethig of that nature. Timothy On Tue, Aug 27, 2013 at 9:15 AM, Brandon Bloom brandon.d.bl...@gmail.comwrote: In every use of channels I've had thus far, nil is better expressed as an empty collection, false, 0, :tick, or some other ground value. I agree completely. But I'll note that you mention false being useful... If you're writing completely general operators, like map, which are *sometimes* quite useful, then you have no choice but to do something like if-recv or explicitly test against nil. It's these Rx style programming methods that make people think they need this feature. I built my little Rx with channels library (asyncx) without intention to use it directly, but because I wanted to learn how to work with channels. I rapidly learned that the techniques are a lot more different than they look. In particular, it's more difficult to write channel process combinators precisely because they are more powerful. However, in practice, each new reusable channel/process combinator yields more complexity than it tends to save. I'd rather intentionally choose strictly less powerful primitives where appropriate and enforce that with encapsulation. With that in mind, if I ever revisit asyncx, I'll probably define push sequences or streams in terms of protocols and deftypes. I'd use core.async to implement them, but only for the lowest level primitives. I'd provide ways to get in to or out of the stream subsystem for interop with channels, but the public interface would take IStream objects. On Tue, Aug 27, 2013 at 10:58 AM, Timothy Baldridge tbaldri...@gmail.com wrote: All your arguments come down to this: I have an arbitrary seq of things I want to send down a channel. It's exactly that concept I that I push against. Everything you've mentioned thus far is a data structure. Channels are not data structures they are concurrency management primitives, treat them as such and I doubt you'll ever have a need for nils in a channel. If we treat channels as ways of co-ordinating concurrent processes, then nil doesn't have a use case. In every use of channels I've had thus far, nil is better expressed as an empty collection, false, 0, :tick, or some other ground value. It's these Rx style programming methods that make people think they need this feature. Timothy On Tue, Aug 27, 2013 at 8:51 AM, Mike Anderson mike.r.anderson...@gmail.com wrote: On 27 August 2013 20:45, Timothy Baldridge tbaldri...@gmail.comwrote: The reason for not allowing nils isn't a complex one, and basically boils down to the following: a) to avoid race conditions, we need a single value to signal the channel is closed. As mentioned, nil is the obvious choice for this as it matches lazy seqs and fits well with the rest of clojure: Agreed that you want a single sentinel value. It doesn't match lazy-seqs at all though: lazy seqs can contain nils just fine. There's a big difference between (next some-lazy-seq) [which could be nil, indicating an empty sequence] and the actual values in the seq [which could also be nil but don't indicate the end of the seq]. (when-let [v (! c)] (process v)) If we chose a different value, this becomes much more ugly: (let [v (! c)] (when-not (= v :async/closed) (process v))) This can be solved easily by providing a macro or some other predicate that knows how to check for the sentinel value correctly. e.g. (when-more [v (! c)] (process v)) b) I question if there are any valid uses for putting nil in a channel. With all due respect to all who have written here, thus far, every complaint about nils and channels boils down to a conversion from seqs to channels. This is the wrong way to look at the problem. Channels are co-ordination primitives not data structures. Simply because a lazy seq looks like a channel, doesn't mean that they should be treated as such. In all the core.async code I've written I've never had to put a nil in a channel, so I'm left with the uncomfortable conclusion that most complaints on this subject are contrived. I could be wrong, but I just haven't seen a valid use case yet. To me it's all about consistency with other Clojure constructs. You can safely put nils in sequences, vectors, lists, sets etc.. nil is a valid value just like anything else. So why can't you put them in a channel? Two use cases I have encountered that motivate this: a) what if you want to send a sequence through a channel? Since nil as a value represents the empty sequence, you have to
Re: Heroku app using core.async?
Hey, I encountered late one night but it was because oss.sonatype.org was temporarily down for scheduled maintenance. Are you still seeing this now? I just pushed to heroku and saw it pull the core.async dep as expected: Retrieving org/clojure/core.async/0.1.0-SNAPSHOT/core.async-0.1.0-20130827.050117-78.pom from sonatype-oss-public On Tue, Aug 27, 2013 at 11:40 AM, Bastien bastiengue...@gmail.com wrote: Hi, I just managed to use core.async for the need I described in my previous email and tried to push this to heroku, but git bitten: Could not find artifact core.async:core.async:jar:0.1.0-SNAPSHOT in clojars (https://clojars.org/repo/) Could not find artifact core.async:core.async:jar:0.1.0-SNAPSHOT in sonatype-oss-public (https://oss.sonatype.org/content/groups/public/) Am I guessing right that heroku prevents downloading libraries from external repositories listed in :repositories? Is anyone using core.async on heroku? Thanks! -- Bastien -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: Heroku app using core.async?
Hi Shaun, Shaun Gilchrist shaunxc...@gmail.com writes: Hey, I encountered late one night but it was because oss.sonatype.org was temporarily down for scheduled maintenance. Are you still seeing this now? I just pushed to heroku and saw it pull the core.async dep as expected: Retrieving org/clojure/core.async/0.1.0-SNAPSHOT/ core.async-0.1.0-20130827.050117-78.pom from sonatype-oss-public Was a typo on my side, I used [core.async 0.1.0...] instead of [org.clojure/core.async 0.1.0...] -- sorry for the noise and thanks for replying. -- Bastien -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
I still don't see why you would want to to arbitrarily limit what you can put down a channel. FWIW, plenty of other concurrency management primitives allow nils as values (java.util.concurrent.AtomicReference, Clojure atoms / refs / agents to name but a few). My motivating use case is the ability to create higher order constructs that communicate via channels, as a way of gluing concurrent processes together. A simplified example: (defn printer [ch id] (go (while true (let [v (! ch)] (prn (str Printer id handled value: v)) (defn sender [ch] (fn [xs] (go (doseq [x xs] (! ch x) (let [ch (chan) pr1 (printer ch 1) pr2 (printer ch 2) sendr (sender ch)] (sendr [foo a]) (sendr [bar])) Using nil as a sentinel appears to prevent such constructs from working with arbitrary Clojure values (or alternatively forces extra wrapping / special case handling that adds complexity and overhead). Furthermore, if different libraries start adopting different protocols / techniques for wrapping nils then the composability of such constructs will be severely restricted. I may be missing something, but this seems like a reasonable use case for core.async to support? Of course, if anyone has an actual technical argument why it is necessary/better to use nil as a sentinel value, I would be delighted to learn of it and would consider myself enlightened. On 27 August 2013 22:58, Timothy Baldridge tbaldri...@gmail.com wrote: All your arguments come down to this: I have an arbitrary seq of things I want to send down a channel. It's exactly that concept I that I push against. Everything you've mentioned thus far is a data structure. Channels are not data structures they are concurrency management primitives, treat them as such and I doubt you'll ever have a need for nils in a channel. If we treat channels as ways of co-ordinating concurrent processes, then nil doesn't have a use case. In every use of channels I've had thus far, nil is better expressed as an empty collection, false, 0, :tick, or some other ground value. It's these Rx style programming methods that make people think they need this feature. Timothy On Tue, Aug 27, 2013 at 8:51 AM, Mike Anderson mike.r.anderson...@gmail.com wrote: On 27 August 2013 20:45, Timothy Baldridge tbaldri...@gmail.com wrote: The reason for not allowing nils isn't a complex one, and basically boils down to the following: a) to avoid race conditions, we need a single value to signal the channel is closed. As mentioned, nil is the obvious choice for this as it matches lazy seqs and fits well with the rest of clojure: Agreed that you want a single sentinel value. It doesn't match lazy-seqs at all though: lazy seqs can contain nils just fine. There's a big difference between (next some-lazy-seq) [which could be nil, indicating an empty sequence] and the actual values in the seq [which could also be nil but don't indicate the end of the seq]. (when-let [v (! c)] (process v)) If we chose a different value, this becomes much more ugly: (let [v (! c)] (when-not (= v :async/closed) (process v))) This can be solved easily by providing a macro or some other predicate that knows how to check for the sentinel value correctly. e.g. (when-more [v (! c)] (process v)) b) I question if there are any valid uses for putting nil in a channel. With all due respect to all who have written here, thus far, every complaint about nils and channels boils down to a conversion from seqs to channels. This is the wrong way to look at the problem. Channels are co-ordination primitives not data structures. Simply because a lazy seq looks like a channel, doesn't mean that they should be treated as such. In all the core.async code I've written I've never had to put a nil in a channel, so I'm left with the uncomfortable conclusion that most complaints on this subject are contrived. I could be wrong, but I just haven't seen a valid use case yet. To me it's all about consistency with other Clojure constructs. You can safely put nils in sequences, vectors, lists, sets etc.. nil is a valid value just like anything else. So why can't you put them in a channel? Two use cases I have encountered that motivate this: a) what if you want to send a sequence through a channel? Since nil as a value represents the empty sequence, you have to put in some extra special case handling with the current core.async model. b) what if you want to write generic code to send all the values in an arbitrary collection through a channel? you would have to wrap/unwrap nils at either end to make this work currently. Both of these, I think, are reasonable and common enough use cases that it's worth supporting them elegantly rather than forcing users to implement their own nil-wrapping functionality. This all being said, there really isn't a technical reason to not allow nils, it just simplifies
eval/macros with functions with metadata
or, the dreaded no matching ctor found exception.
Is there a way to write the function
(defn eval-at-one [f] (eval `(~f 1)))
such that it works when invoked like this:
(eval-at-one (fn [x] x))
;; -- 1
and like this
(eval-at-one (with-meta (fn [x] x) {}))
;; - IllegalArgumentException No matching ctor found for class
clojure.lang.AFunction$1 clojure.lang.Reflector.invokeConstructor
(Reflector.java:163)
?
I thought that the object returned by with-meta might be hanging onto the
original, metadata-less object, which could then be retrieved and used
without difficulty, but this appears not to be the case.
--
Ben Wolfson
Human kind has used its intelligence to vary the flavour of drinks, which
may be sweet, aromatic, fermented or spirit-based. ... Family and social
life also offer numerous other occasions to consume drinks for pleasure.
[Larousse, Drink entry]
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Re: core.async - handling nils
On Wed 28 Aug 2013 at 09:38:06AM +0800, Mike Anderson wrote: Of course, if anyone has an actual technical argument why it is necessary/better to use nil as a sentinel value, I would be delighted to learn of it and would consider myself enlightened. Forgive me if someone already mentioned this, but isn't this simply a consequence of building on the existing Java Queue implementations? Quoting http://docs.oracle.com/javase/7/docs/api/java/util/Queue.html: Queue implementations generally do not allow insertion of null elements, although some implementations, such as LinkedList, do not prohibit insertion of null. Even in the implementations that permit it, null should not be inserted into a Queue, as null is also used as a special return value by the poll method to indicate that the queue contains no elements. I think most would agree with you that a configurable sentinel value is best (I like using ::namespaced-keywords myself), but the existing machinery has already decided on null, so that's what we have. guns pgp6xD5GT3rVU.pgp Description: PGP signature
Re: core.async - handling nils
Well, that's certainly a good explanation of why core.async works the way it does now - it's a natural and sensible starting point to build on Java Queues. I don't think that this necessarily implies that we have to follow this model in the future Clojure API though. The Java designers didn't always get everything right :-) There's no reason I can see why core.async can't internally substitute its own nil-representing value into the underlying Java infrastructure. And this would free users of core.async from the burden of doing this translation every time that the transmission of nil values is desired. As for configurable sentinel value: I'm less sure that there's a need for this. In fact, I think it's more useful to guarantee a standard sentinel value so that different channel-handling code can interoperate. I just think that this sentinel shouldn't be nil (or any other regular Clojure value). A simple singleton object that is privately owned by core.async should suffice? On Wednesday, 28 August 2013 09:54:51 UTC+8, guns wrote: On Wed 28 Aug 2013 at 09:38:06AM +0800, Mike Anderson wrote: Of course, if anyone has an actual technical argument why it is necessary/better to use nil as a sentinel value, I would be delighted to learn of it and would consider myself enlightened. Forgive me if someone already mentioned this, but isn't this simply a consequence of building on the existing Java Queue implementations? Quoting http://docs.oracle.com/javase/7/docs/api/java/util/Queue.html: Queue implementations generally do not allow insertion of null elements, although some implementations, such as LinkedList, do not prohibit insertion of null. Even in the implementations that permit it, null should not be inserted into a Queue, as null is also used as a special return value by the poll method to indicate that the queue contains no elements. I think most would agree with you that a configurable sentinel value is best (I like using ::namespaced-keywords myself), but the existing machinery has already decided on null, so that's what we have. guns -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Can you explain the result of a expression?
Hi, (take 1 (map #(do (print \.) %) (range))) result: (0) I think it should be (.0), why? thank you! -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: Can you explain the result of a expression?
chunked lazy sequences On Wednesday, 28 August 2013 12:51:27 UTC+10, ljcp...@gmail.com wrote: Hi, (take 1 (map #(do (print \.) %) (range))) result: (0) I think it should be (.0), why? thank you! -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Easiest way to map over leaf nodes of nested sequence
I feel like this question has been asked about a trillion times, but I was having a hard time finding a straight answer. Is there a really straightforward way in the standard library or in one of the contrib libraries to do something like this: (nested-map inc '(1 (2 3) (4 (5 (6) === '(2 (3 4) (5 (6 (7 -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: Easiest way to map over leaf nodes of nested sequence
Clojure.walk On Aug 27, 2013 10:05 PM, JvJ kfjwhee...@gmail.com wrote: I feel like this question has been asked about a trillion times, but I was having a hard time finding a straight answer. Is there a really straightforward way in the standard library or in one of the contrib libraries to do something like this: (nested-map inc '(1 (2 3) (4 (5 (6) === '(2 (3 4) (5 (6 (7 -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
On Tue 27 Aug 2013 at 07:42:53PM -0700, Mikera wrote: On Wednesday, 28 August 2013 09:54:51 UTC+8, guns wrote: On Wed 28 Aug 2013 at 09:38:06AM +0800, Mike Anderson wrote: Of course, if anyone has an actual technical argument why it is necessary/better to use nil as a sentinel value, I would be delighted to learn of it and would consider myself enlightened. Forgive me if someone already mentioned this, but isn't this simply a consequence of building on the existing Java Queue implementations? Quoting http://docs.oracle.com/javase/7/docs/api/java/util/Queue.html: Queue implementations generally do not allow insertion of null elements, although some implementations, such as LinkedList, do not prohibit insertion of null. Even in the implementations that permit it, null should not be inserted into a Queue, as null is also used as a special return value by the poll method to indicate that the queue contains no elements. I don't think that this necessarily implies that we have to follow this model in the future Clojure API though. The Java designers didn't always get everything right :-) I agree with you that this is an inconvenience. The bit about avoiding null even in collections that support null elements because poll uses null as a sentinel value is a classic leaky abstraction. That said, I haven't found designing around it to be a terrible nuisance. I often use queues as messaging channels, so it is natural to simply send maps or tuples instead of atomic values. As for configurable sentinel value: I'm less sure that there's a need for this. In fact, I think it's more useful to guarantee a standard sentinel value so that different channel-handling code can interoperate. I just think that this sentinel shouldn't be nil (or any other regular Clojure value). A simple singleton object that is privately owned by core.async should suffice? Oh, I was confused; I was thinking about sentinel values in user code. Yes, I imagine a single private (Object.) would work just fine, with very little overhead. guns pgp0C89I2s0Ka.pgp Description: PGP signature
Re: Easiest way to map over leaf nodes of nested sequence
I suppose that works, but it seems a little inelegant to do this: (prewalk #(if (sequential? %) % (f %)) xs) instead of just (prewalk f xs) On Tuesday, 27 August 2013 20:06:38 UTC-7, gfredericks wrote: Clojure.walk On Aug 27, 2013 10:05 PM, JvJ kfjwh...@gmail.com javascript: wrote: I feel like this question has been asked about a trillion times, but I was having a hard time finding a straight answer. Is there a really straightforward way in the standard library or in one of the contrib libraries to do something like this: (nested-map inc '(1 (2 3) (4 (5 (6) === '(2 (3 4) (5 (6 (7 -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clo...@googlegroups.comjavascript: Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+u...@googlegroups.com javascript: For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+u...@googlegroups.com javascript:. For more options, visit https://groups.google.com/groups/opt_out. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
On Wed, Aug 28, 2013 at 12:18 PM, guns s...@sungpae.com wrote: Oh, I was confused; I was thinking about sentinel values in user code. Yes, I imagine a single private (Object.) would work just fine, with very little overhead. First, I'd hope that sentinel values would be handled by the back-end implementation, as we're seeing core.sync implemented on other systems like ZeroMQ already. Second, as (Object.) doesn't play nicely over the wire, a random UUID or similar value would be much preferred. Third, I'd recommend reviewing, http://clojure.com/blog/2013/06/28/clojure-core-async-channels.html to understand why core.async is not just a better queue. Fourth, if you dislike how core.async works, just wrap it in your own library so it works the way you'd like. It looks like core.async-with-nil is available on Clojars. ;) With nil, without nil, it's just bike shedding. Clojure gives you the freedom to do it the way you want. -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
Re: core.async - handling nils
On Wed 28 Aug 2013 at 12:50:19PM +0900, Alan Busby wrote: On Wed, Aug 28, 2013 at 12:18 PM, guns s...@sungpae.com wrote: Oh, I was confused; I was thinking about sentinel values in user code. Yes, I imagine a single private (Object.) would work just fine, with very little overhead. Third, I'd recommend reviewing, http://clojure.com/blog/2013/06/28/clojure-core-async-channels.html to understand why core.async is not just a better queue. In my mind, core.async is a nice marriage of BlockingQueues, async processing, and a supercharged POSIX select(2) that works on queue objects. Nothing about these ideas necessarily requires that null be reserved by the channel implementation. Fourth, if you dislike how core.async works, just wrap it in your own library so it works the way you'd like. It looks like core.async-with-nil is available on Clojars. ;) With nil, without nil, it's just bike shedding. Clojure gives you the freedom to do it the way you want. Rich Hickey, from: http://clojure.com/blog/2013/06/28/clojure-core-async-channels.html While the library is still in an early state, we are ready for people to start trying it out and giving us feedback. I think mikera is trying to be constructive. For my own part, I am quite ambivalent since I am already used to avoiding pushing nulls onto Queues. I am quite happy to accept that this is an implementation detail and move on, but I can also see why it might be worth it to support nil channel values to avoid confusing users that are not familiar with this quirk of java.util.Queue. guns pgpQWVvS0WkaO.pgp Description: PGP signature
Re: core.async - handling nils
On 28 August 2013 11:50, Alan Busby thebu...@gmail.com wrote: On Wed, Aug 28, 2013 at 12:18 PM, guns s...@sungpae.com wrote: Oh, I was confused; I was thinking about sentinel values in user code. Yes, I imagine a single private (Object.) would work just fine, with very little overhead. First, I'd hope that sentinel values would be handled by the back-end implementation, as we're seeing core.sync implemented on other systems like ZeroMQ already. Second, as (Object.) doesn't play nicely over the wire, a random UUID or similar value would be much preferred. Hi Alan, Agreed on all the above. The issue is not so much what sentinel value is used internally, but what sentinel value gets exposed to user code. Third, I'd recommend reviewing, http://clojure.com/blog/2013/06/28/clojure-core-async-channels.html to understand why core.async is not just a better queue. Fourth, if you dislike how core.async works, just wrap it in your own library so it works the way you'd like. It looks like core.async-with-nil is available on Clojars. ;) That's precisely what I'm trying to avoid, and the reason why I've been raising the topic here - the last thing we want in the ecosystem is more fragmentation with incompatible subsystems and protocols. That's the Lisp Curse all over again. I think we should aspire to better in the Clojure community - which means working together to make the best implementation possible and rallying around it. Sending nil as a value over channels is clearly a significant issue if people are willing to fork or create a new wrapper for core.async in order to achieve it. Better, in my view, to make a breaking change to core.async now to fix this issue rather than encouraging a free-for-all. I'm reminded of Rich Hickey's keynote The Language of the System, which emphasised composing systems out of simple services that communicate via values. core.async would IMHO be a much more useful tool for realising this sort of vision if it is able transmit arbitrary Clojure values (i.e. including nil). -- -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
