"For comprehension" is a another syntax to use map, flatMap and withFilter (or filter) methods.
yield keyword is used to aggregate values in the resulting structure.
This composition can be used on any type implementing this methods, like List, Option, Future...
| trait BinaryOperation[T] { | |
| def apply(a: T, b: T): T | |
| } | |
| trait AssociativeBinaryOperation[T] extends BinaryOperation[T] | |
| trait Reduce[F[_]] { | |
| def apply[T](xs: F[T])(op: BinaryOperation[T]): T | |
| } |
| trait Lit[T] { | |
| def lit(x: Int): T | |
| } | |
| trait Add[T] { | |
| def add(x: T, y: T): T | |
| } | |
| trait Mul[T] { | |
| def mul(x: T, y: T): T |
| import scala.language.experimental.macros | |
| import scala.reflect.macros.blackbox | |
| object Test { | |
| def foo1[A, B]: Unit = macro impl[A, B] | |
| def foo2[A]: Unit = macro impl[A, Option[Int]] | |
| def impl[A: c.WeakTypeTag, B: c.WeakTypeTag](c: blackbox.Context): c.Expr[Unit] = { | |
| import c.universe._ | |
| c.echo(c.enclosingPosition, s"A=${weakTypeOf[A]}, B=${weakTypeOf[B]}") |
| import com.google.common.primitives.Ints | |
| import scala.collection.breakOut | |
| trait Serializable[From, To] { | |
| def serialize(x: From): To | |
| } | |
| trait Deserializable[From, To] { | |
| def deserialize(x: From): To | |
| } |
| import com.typesafe.config.ConfigObject | |
| import pureconfig._ | |
| import pureconfig.error.{CannotParse, ConfigReaderFailures} | |
| sealed trait Enigma | |
| object Enigma { | |
| case class Foo(value: Int) extends Enigma | |
| case object Bar extends Enigma | |
| } |
| import com.google.common.collect.ImmutableMap | |
| import com.spotify.docker.client.messages.HostConfig | |
| import com.spotify.docker.client.shaded.com.fasterxml.jackson.annotation.JsonProperty | |
| class ExtendedHostConfig(h: HostConfig) extends HostConfig { | |
| @JsonProperty("Sysctls") | |
| def sysctls(): ImmutableMap[String, String] = ImmutableMap.of( | |
| "net.ipv4.tcp_keepalive_time", "15", | |
| "net.ipv4.tcp_keepalive_intvl", "5", | |
| "net.ipv4.tcp_keepalive_probes", "3" |
| <?xml version="1.0" encoding="UTF-8"?> | |
| <configuration> | |
| <contextListener class="ch.qos.logback.classic.jul.LevelChangePropagator"/> | |
| <property name="default.pattern" value="%date{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%.15thread] %logger{26} - %msg%n"/> | |
| <property name="logback.file.final-directory" value="${logback.file.directory:-${waves.directory}/log}"/> | |
| <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> | |
| <target>System.out</target> | |
| <filter class="ch.qos.logback.classic.filter.ThresholdFilter"> |
Удаляем посты на стене
$$('.ui_actions_menu_item')
.filter(function (x) {
var attr = x.getAttributeNode('onclick');
if (attr == null) return false;
return attr.value.indexOf('delete') > 0;
})
.forEach(function (x) {
| val xs: List[Int] = List(1, 1, 2, 1, 1) | |
| val result = xs.foldLeftM(0) { | |
| case (r, x) => | |
| println(s"r=$r, x=$x") | |
| if (x % 2 == 0) Left("even") | |
| else Right(r + x) | |
| } | |
| println(result) | |
| /* |