package main
type Numer interface {
	getNum() int64
}
type Num struct {
	num int64
}
func (n *Num) getNum() int64 {
	return n.num
}
func main() {
}
func sumConcrete(s []*Num) int64 {
	var sum int64
	for _, v := range s {
		sum += v.getNum()
	}
	return sum
}
func sumInterface(s []Numer) int64 {
	var sum int64
	for _, v := range s {
		sum += v.getNum()
	}
	return sum
}
func sum2concrete(s []interface{}) int64 {
	var sum int64
	for _, v := range s {
		sum += v.(*Num).getNum()
	}
	return sum
}
func sum2interface(s []interface{}) int64 {
	var sum int64
	for _, v := range s {
		sum += v.(Numer).getNum()
	}
	return sum
}

package main
import (
	"math/rand"
	"testing"
)
func BenchmarkSumT(b *testing.B) {
	//prepare data
	length := 10000
	data := make([]*Num, length)
	its := make([]Numer, length)
	eits := make([]interface{}, length)
	for i := 0; i < length; i++ {
		data[i] = &Num{int64(rand.Int31n(100))}
		its[i] = data[i]
		eits[i] = data[i]
	}
	b.Run("Concrete", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			sumConcrete(data)
		}
	})
	b.Run("Interface", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			sumInterface(its)
		}
	})
	b.Run("i2concrete", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			sum2concrete(eits)
		}
	})
	b.Run("i2interface", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			sum2interface(eits)
		}
	})
}

➜  vscode go test -bench Sum
goos: linux
goarch: amd64
pkg: pc.chen/test/vscode
BenchmarkSumT/Concrete-4                  300000              4881 ns/op
BenchmarkSumT/Interface-4                  50000             24830 ns/op
BenchmarkSumT/i2concrete-4                200000              7630 ns/op
BenchmarkSumT/i2interface-4                10000            101115 ns/op
PASS
ok      pc.chen/test/vscode     5.645s

➜  vscode go test -bench Sum
goos: linux
goarch: amd64
pkg: pc.chen/test/vscode
BenchmarkSumT/Num-4               300000              4513 ns/op
BenchmarkSumT/Numer-4              50000             30177 ns/op
BenchmarkSumT/toNum-4             200000              8354 ns/op
BenchmarkSumT/toNumer-4            10000            116636 ns/op
PASS
ok      pc.chen/test/vscode     6.147s

[WARN] [03/17/2018 21:51:38.769] [cluster-akka.remote.default-remote-dispatcher-91] [akka.remote.Remoting] Tried to associate with unreachable remote address [akka.tcp://cluster@10.104.3.35:7712]. Address is now gated for 5000 ms, all messages to this address will be delivered to dead letters. Reason: [The remote system has quarantined this system. No further associations to the remote system are possible until this system is restarted.]

[INFO] [03/13/2018 21:36:12.659] [cluster-akka.remote.default-remote-dispatcher-35339] [akka.remote.Remoting] Quarantined address [akka.tcp://cluster@10.104.3.36:7712] is still unreachable or has not been restarted. Keeping it quarantined.

[ERROR] [03/17/2018 21:51:37.662] [cluster-akka.remote.default-remote-dispatcher-127527] [akka.remote.Remoting] Association to [akka.tcp://cluster@10.104.3.36:7712] with UID [1258718596] irrecoverably failed. Quarantining address.
java.util.concurrent.TimeoutException: Remote system has been silent for too long. (more than 48.0 hours)
        at akka.remote.ReliableDeliverySupervisor$$anonfun$idle$1.applyOrElse(Endpoint.scala:383)
        at akka.actor.Actor.aroundReceive(Actor.scala:517)
        at akka.actor.Actor.aroundReceive$(Actor.scala:515)
        at akka.remote.ReliableDeliverySupervisor.aroundReceive(Endpoint.scala:203)
        at akka.actor.ActorCell.receiveMessage(ActorCell.scala:527)
        at akka.actor.ActorCell.invoke(ActorCell.scala:496)
        at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:257)
        at akka.dispatch.Mailbox.run(Mailbox.scala:224)
        at akka.dispatch.Mailbox.exec(Mailbox.scala:234)
        at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
        at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
        at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
        at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
[03/17/2018 21:51:37.749] [cluster-akka.actor.default-dispatcher-105] [akka.tcp://cluster@10.104.3.35:7712/system/cluster/core/daemon] Cluster Node [akka.tcp://cluster@10.104.3.35:7712] - Marking node as TERMINATED [akka.tcp://cluster@10.104.3.36:7712], due to quarantine. Node roles [dc-default]

akka.cluster.use-dispatcher = cluster-dispatcher
cluster-dispatcher {
  type = "Dispatcher"
  executor = "fork-join-executor"
  fork-join-executor {
    parallelism-min = 2
    parallelism-max = 4
  }
}

type MyInt int
var i int
var j MyInt

// Reader is the interface that wraps the basic Read method.
type Reader interface {
    Read(p []byte) (n int, err error)
}
// Writer is the interface that wraps the basic Write method.
type Writer interface {
    Write(p []byte) (n int, err error)
}

var r io.Reader
r = os.Stdin
r = bufio.NewReader(r)
r = new(bytes.Buffer)
// and so on

interface{}

f, err := os.Open(name)
d, err := f.Stat()

for i, j := 0, len(a)-1; i < j; i, j = i+1, j-1 {
    a[i], a[j] = a[j], a[i]
}

func shouldEscape(c byte) bool {
    switch c {
    case ' ', '?', '&', '=', '#', '+', '%':
        return true
    }
    return false
}

bin/
    hello                          # command executable
    outyet                         # command executable
pkg/
    linux_amd64/
        github.com/golang/example/
            stringutil.a           # package object
src/
    github.com/golang/example/
        .git/                      # Git repository metadata
	hello/
	    hello.go               # command source
	outyet/
	    main.go                # command source
	    main_test.go           # test source
	stringutil/
	    reverse.go             # package source
	    reverse_test.go        # test source
    golang.org/x/image/
        .git/                      # Git repository metadata
	bmp/
	    reader.go              # package source
	    writer.go              # package source
    ... (many more repositories and packages omitted) ...

CREATE / ALTER / DROP DATABASE
CREATE /ALTER / DROP / RENAME / TRUNCATE TABLE
CREATE / DROP INDEX
CREATE / DROP EVENT
CREATE / DROP FUNCTION
CREATE / DROP PROCEDURE

SET autocommit = 0;

while(){
}
--------
do{
}while();

for(i <- 1 to 10){
}// 将循环1,2,3...10，共10次
-----
for(i <- 1 until 10){
}// 将循环1，2,3...9，共9次

for( a <- 1 to 3; b <- 1 to 3){
    println( "Value of a: " + a );
    println( "Value of b: " + b );
}

class Outer {
    class Inner {
        private def f() { println("f") }
        class InnerMost {
            f() // OK
        }
    }
    (new Inner).f() // Error: f is not accessible
}