| jruby -S ast -e 'i += 1; i = i + 1' | |
| AST: | |
| RootNode 0 | |
| BlockNode 0 | |
| LocalAsgnNode:i 0 | |
| CallNode:+ 0 | |
| LocalVarNode:i 0 | |
| ArrayNode 0 | |
| FixnumNode 0 | |
| , null |
Let's say you are implementing an API and decide to return a base error response in common error situations such as BadRequest, NotFound etc.
final case class Error(code: String, description: String)If you are returning an error response, your assumption would probably be that such responses should contain at least one error.
| // Alternative to sealed abstract case class pattern for Scala 2.12.2+ | |
| // Benefits: | |
| // - 1 final class instead of 1 sealed class + anonymous subclass | |
| // - portable to Scala 3 regardless of opaque types | |
| // - less boilerplate | |
| final case class Angle private (toDegrees: Int) { | |
| // Define our own `copy` method to suppress synthetic one | |
| // Add private to prevent it from being used | |
| def copy(degrees: Int = toDegrees): Angle = Angle.fromDegrees(degrees) |
L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns
Compress 1K bytes with Zippy ............. 3,000 ns = 3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns = 20 µs
SSD random read ........................ 150,000 ns = 150 µs
Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs
| /* | |
| This piece of commented code aims to clarify some | |
| misconceptions between several advanced concepts | |
| in pure functional programming/category theory: | |
| free monads, finally tagless approach, algebraic | |
| effects. | |
| These concepts are actually very close. They rely | |
| on similar concepts and even represent the "same" | |
| object (up to isomorphism!) from the theoretical |
| 2019-03-29 16:46:51 | |
| "Ruby-0-Fiber-286" - Thread t@363 | |
| java.lang.Thread.State: WAITING | |
| at java.base@11.0.2/jdk.internal.misc.Unsafe.park(Native Method) | |
| - parking to wait for <69439394> (a java.util.concurrent.SynchronousQueue$TransferStack) | |
| at java.base@11.0.2/java.util.concurrent.locks.LockSupport.park(LockSupport.java:194) | |
| at java.base@11.0.2/java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460) | |
| at java.base@11.0.2/java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:361) | |
| at java.base@11.0.2/java.util.concurrent.SynchronousQueue.put(SynchronousQueue.java:873) |
| 2019-03-29 17:33:39 | |
| "Ruby-0-Fiber-25" - Thread t@1172 | |
| java.lang.Thread.State: WAITING | |
| at java.base@11.0.2/jdk.internal.misc.Unsafe.park(Native Method) | |
| - parking to wait for <4e7da9fc> (a java.util.concurrent.SynchronousQueue$TransferStack) | |
| at java.base@11.0.2/java.util.concurrent.locks.LockSupport.park(LockSupport.java:194) | |
| at java.base@11.0.2/java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460) | |
| at java.base@11.0.2/java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:361) |
| Exception in thread "main" java.lang.ExceptionInInitializerError | |
| at org.torquebox.mojo.mavengem.wagon.MavenGemWagon.rubygemsFactory(MavenGemWagon.java:88) | |
| at org.torquebox.mojo.mavengem.wagon.MavenGemWagon.newConnection(MavenGemWagon.java:102) | |
| at org.torquebox.mojo.mavengem.wagon.MavenGemWagon.fillInputData(MavenGemWagon.java:64) | |
| at org.apache.maven.wagon.StreamWagon.getInputStream(StreamWagon.java:126) | |
| at org.apache.maven.wagon.StreamWagon.getIfNewer(StreamWagon.java:88) | |
| at org.apache.maven.wagon.StreamWagon.get(StreamWagon.java:61) | |
| at org.eclipse.aether.transport.wagon.WagonTransporter$GetTaskRunner.run(WagonTransporter.java:567) | |
| at org.eclipse.aether.transport.wagon.WagonTransporter.execute(WagonTransporter.java:435) | |
| at org.eclipse.aether.transport.wagon.WagonTransporter.get(WagonTransporter.java:412) |
| import scala.collection.{immutable, mutable, GenTraversableOnce} | |
| import scala.collection.generic.CanBuildFrom | |
| object GroupableOps { | |
| implicit class ToGroupable[A, Coll[X] <: GenTraversableOnce[X]](coll: Coll[A]) { | |
| // https://github.com/scala/scala/blob/v2.13.0-M5/src/library/scala/collection/Iterable.scala#L578 | |
| def groupMap[K, B, To](key: A => K)(f: A => B) | |
| (implicit bf: CanBuildFrom[Coll[A], B, To]): immutable.Map[K, To] = { |
| /* | |
| * This test shows that without a fork, execution is purely mono-fiber and sequential. | |
| */ | |
| object TestZioExecSemantic { | |
| val rt = new DefaultRuntime {} | |
| trait LOG { | |
| def apply(s: String): UIO[Unit] | |
| } | |
| def makeLog = UIO(new LOG { | |
| val zero = System.currentTimeMillis() |