├── .gitignore ├── CHANGELOG.md ├── LICENSE ├── README.md ├── doc └── intro.md ├── project.clj ├── src └── functional_core_async │ ├── core.clj │ └── examples.clj └── test └── functional_core_async └── core_test.clj /.gitignore: -------------------------------------------------------------------------------- 1 | /target 2 | /classes 3 | /checkouts 4 | pom.xml 5 | pom.xml.asc 6 | *.jar 7 | *.class 8 | /.lein-* 9 | /.nrepl-port 10 | .hgignore 11 | .hg/ 12 | -------------------------------------------------------------------------------- /CHANGELOG.md: -------------------------------------------------------------------------------- 1 | # Change Log 2 | All notable changes to this project will be documented in this file. This change log follows the conventions of [keepachangelog.com](http://keepachangelog.com/). 3 | 4 | ## [Unreleased] 5 | ### Changed 6 | - Add a new arity to `make-widget-async` to provide a different widget shape. 7 | 8 | ## [0.1.1] - 2017-11-10 9 | ### Changed 10 | - Documentation on how to make the widgets. 11 | 12 | ### Removed 13 | - `make-widget-sync` - we're all async, all the time. 14 | 15 | ### Fixed 16 | - Fixed widget maker to keep working when daylight savings switches over. 17 | 18 | ## 0.1.0 - 2017-11-10 19 | ### Added 20 | - Files from the new template. 21 | - Widget maker public API - `make-widget-sync`. 22 | 23 | [Unreleased]: https://github.com/your-name/functional-core-async/compare/0.1.1...HEAD 24 | [0.1.1]: https://github.com/your-name/functional-core-async/compare/0.1.0...0.1.1 25 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | THE ACCOMPANYING PROGRAM IS PROVIDED UNDER THE TERMS OF THIS ECLIPSE PUBLIC 2 | LICENSE ("AGREEMENT"). 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No party to this 212 | Agreement will bring a legal action under this Agreement more than one year 213 | after the cause of action arose. Each party waives its rights to a jury trial 214 | in any resulting litigation. 215 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | ``` 2 | He had found a Nutri-Matic machine which had provided him with 3 | a plastic cup filled with a liquid that was almost, but not quite, 4 | entirely unlike tea. 5 | 6 | The way it functioned was very interesting. When the Drink button 7 | was pressed it made an instant but highly detailed examination of 8 | the subject's taste buds, a spectroscopic analysis of the subject's 9 | metabolism and then sent tiny experimental signals down the neural 10 | pathways to the taste centers of the subject's brain to see what 11 | was likely to go down well. However, no one knew quite why it did 12 | this because it invariably delivered a cupful of liquid that was 13 | almost, but not quite, entirely unlike tea. 14 | ``` 15 | *from The Hitchhiker's Guide to the Galaxy* 16 | 17 | # functional-core-async 18 | 19 | CSP - S = Communicating Processes = Green Threads! 20 | 21 | ## Why 22 | 23 | - It makes writing concurrent software much simpler by getting data out of callbacks 24 | through the use of magic portals called `channels`. 25 | - It provides green threads via `go` blocks that can park and be multiplexed over JVM threads, 26 | and communicate over channels. 27 | - It can be ported to other systems and languages in a rather straightforward manner. 28 | For example, here is [a javascript port](https://github.com/divs1210/coroutines.js). 29 | 30 | ## Differences from [`core.async`](https://github.com/clojure/core.async) 31 | - CSP - S: making callbacky code look sequential requires access to compiler. This is avoided to aid portability. 32 | - `>!` and `!` or `!! ch %)) 71 | (println "but blocks on accessing response :(") 72 | (let [resp (!! ch %)) 95 | (go 96 | (!! ch %)) 109 | (go hot-dogs-left 0) 133 | (go! [out "hot dog"] 136 | (hot-dog-machine in out (dec hot-dogs-left))) 137 | (go>! [out "wilted lettuce"] 138 | (hot-dog-machine in out hot-dogs-left)))))) 139 | ``` 140 | Let's give it a try: 141 | ```clojure 142 | (let [in (chan) 143 | out (chan) 144 | _ (hot-dog-machine in out 2)] 145 | (>!! in "pocket lint") 146 | (println (!! in 3) 149 | (println (!! in 3) 152 | (println ( wilted lettuce 154 | ; => hotdog 155 | ; => hotdog 156 | ``` 157 | 158 | There's also `goloop` and `goconsume`. Read the source to know more! 159 | 160 | ## TODO 161 | 162 | * preserve thread-local bindings in `go` blocks 163 | * optimize scheduler: replace round-robin scheduling with per-channel queues and listeners 164 | * `close!` 165 | * `alts!` 166 | 167 | ## License 168 | 169 | Copyright © 2017 Divyansh Prakash 170 | 171 | Distributed under the Eclipse Public License either version 1.0 172 | -------------------------------------------------------------------------------- /doc/intro.md: -------------------------------------------------------------------------------- 1 | # Introduction to functional-core-async 2 | 3 | TODO: write [great documentation](http://jacobian.org/writing/what-to-write/) 4 | -------------------------------------------------------------------------------- /project.clj: -------------------------------------------------------------------------------- 1 | (defproject functional-core-async "0.1.0-SNAPSHOT" 2 | :description "functional implementation of core.async" 3 | :url "http://example.com/FIXME" 4 | :license {:name "Eclipse Public License" 5 | :url "http://www.eclipse.org/legal/epl-v10.html"} 6 | :dependencies [[org.clojure/clojure "1.8.0"]]) 7 | -------------------------------------------------------------------------------- /src/functional_core_async/core.clj: -------------------------------------------------------------------------------- 1 | (ns functional-core-async.core 2 | (:import [java.util.concurrent ArrayBlockingQueue TimeUnit])) 3 | 4 | ;; CHANNELS 5 | ;; ======== 6 | (defn chan 7 | "Returns a new channel." 8 | ([] 9 | (chan 1)) 10 | ([width] 11 | (chan width true)) 12 | ([width fifo?] 13 | (ArrayBlockingQueue. width fifo?))) 14 | 15 | 16 | ;; BLOCKING CHANNEL OPS 17 | ;; ==================== 18 | (defn ^:private poll! 19 | "Returns value if available in given duration, or ::nil." 20 | [^ArrayBlockingQueue ch microseconds] 21 | (or (.poll ch microseconds TimeUnit/MICROSECONDS) 22 | ::nil)) 23 | 24 | 25 | (defn !! 32 | "Puts x on the channel. Thread safe, blocking." 33 | [^ArrayBlockingQueue ch x] 34 | (.put ch x)) 35 | 36 | 37 | ;; ASYNC CHANNEL OPS 38 | ;; ================= 39 | (defn ! 49 | "Executes body when v is put on the channel. 50 | Can be used only within `go` blocks!" 51 | [ch v body-fn] 52 | ^{:type ::>!} 53 | {:ch ch 54 | :fn body-fn 55 | :val v}) 56 | 57 | 58 | ;; ASYNC EVENT LOOP 59 | ;; ================ 60 | (defonce ^:private async-ch 61 | ;; 1M `go` blocks at a time 62 | (chan 1000000 false)) 63 | 64 | 65 | (defn schedule-async 66 | "Puts a job on the asynchronous job queue. 67 | `f`: a 0-arity fn to be run asynchronously 68 | `ok`: callback called with the result of (f)" 69 | [f ok] 70 | (>!! async-ch [f ok]) 71 | nil) 72 | 73 | 74 | (defn ^:private execute 75 | "Wait for, pick up, and execute one job 76 | from the job queue." 77 | [] 78 | (let [[f ok] (! 89 | (let [chan (:ch res) 90 | val (:val res)] 91 | (if (locking chan 92 | (pos? (.remainingCapacity chan))) 93 | (do 94 | (>!! chan val) 95 | (ok ((:fn res)))) 96 | (schedule-async (fn [] res) ok))) 97 | 98 | ;; else 99 | (ok res)))) 100 | 101 | 102 | (defonce ^:private async-executors 103 | (let [cores (.availableProcessors (Runtime/getRuntime))] 104 | (doall 105 | (for [_ (range cores)] 106 | (future 107 | (while true 108 | (try 109 | (execute) 110 | (catch Exception e 111 | (.printStackTrace e))))))))) 112 | 113 | 114 | ;; Lightweight Threads 115 | ;; =================== 116 | (defn go* 117 | "Evaluates (f) on the `async-executor` thread, 118 | returning a channel that gives the returned value." 119 | [f] 120 | (let [ch (chan)] 121 | (schedule-async f #(>!! ch %)) 122 | ch)) 123 | 124 | 125 | (defmacro go 126 | "Executes the body on the `async-executor` thread, 127 | returning a channel that gives the returned value." 128 | [& body] 129 | `(go* (fn [] ~@body))) 130 | 131 | 132 | (defmacro go! 140 | "Puts v on ch. 141 | Returns a channel." 142 | [[ch v] & body] 143 | `(go (>! ~ch ~v (fn [] ~@body)))) 144 | 145 | 146 | (defn goloop* 147 | "Calls (f gorecur initial-state). 148 | f can call (gorecur state) to loop." 149 | [f initial-state] 150 | (letfn [(gorecur [& [state]] 151 | (goloop* f state))] 152 | (go 153 | (f gorecur initial-state)))) 154 | 155 | 156 | (defmacro goloop 157 | "Like `loop`, but runs each iteration 158 | on a separate go block, and doesn't 159 | block the main thread. 160 | Call (gorecur state) in body to loop." 161 | [[var initial-state] & body] 162 | `(goloop* (fn [~'gorecur ~var] 163 | ~@body) 164 | ~initial-state)) 165 | 166 | 167 | (defn goconsume* 168 | "Calls (f v gorecur) when v is 169 | received on ch. 170 | f can call (gorecur) to wait for 171 | another v on ch." 172 | [ch f] 173 | (goloop [_ nil] 174 | (go!! ch %)) 40 | (println "async :)") 41 | (println "but blocks on read :(") 42 | (let [resp (!! ch %)) 54 | (println "async :)") 55 | (go 56 | ( hc 0) 70 | (go! [out "hot dog"] 73 | (recurse (dec hc))) 74 | (go>! [out "wilted lettuce"] 75 | (recurse hc))))))) 76 | 77 | #_(let [in (chan) 78 | out (chan) 79 | _ (hot-dog-machine in out 2)] 80 | (>!! in "pocket lint") 81 | (println (!! in 3) 84 | (println (!! in 3) 87 | (println (!! ch 1) 8 | (is (= 1 (!! ch %)) 16 | (is (= 2 (!! ch 1) 25 | (is (= 1 @res) 26 | "go blocks should be async.")) 27 | 28 | (let [ch (chan) 29 | res (promise)] 30 | (go (!! ch 42)) 32 | (is (= 42 @res) 33 | "go blocks should not block each other."))) 34 | 35 | 36 | (deftest alts-test 37 | (let [ch (chan) 38 | to (timeout 1000) 39 | [v c] (alts! [ch to]) 40 | res (chan)] 41 | (condp = c 42 | ch (>!! res :ch) 43 | to (>!! res :to)) 44 | (is (= :to (