Сhannels — почему это круто для мультизадачности, defer и другие особенности Go.

1. C-spirit reborn, or why
Go was bound to be
created
BOHDAN TROTSENKO

2. C, C++
CMyClass instance;
instance.DoSomething();

3. …
void *p = get_memory_on_stack(sizeof(CMyClass));
try {
p.ctr();
p.DoSomething();
} catch (...)
{
p.~dstr();
}

4. Imperative Languages
C, C++
Go
Java, C#

5. Enterprise principle
The straight-forward way to do
things is the right way to do things

6. func FillInp(path string, res chan string) {
var (
file *os.File
err error
)
defer close(res)
if file, err = os.Open(path); err != nil {
fmt.Println("Error opening file", err)
return
}
defer file.Close()

7. … some horrible code
sem := make(chan bool, parallelism) // semaphore
for perm := 0; perm < parallelism; perm++ {
sem <- true // add initial values
}
for cs := 0; cs < len(cases); cs++ {
<-sem // read values
thiscase := cs
go func() {
Solve(&cases[thiscase])
sem <- true // permit others to continue
}()
}

10. protobuf
message Test {
required string label = 1;
optional int32 type = 2 [default=77];
repeated int64 reps = 3;
optional group OptionalGroup = 4 {
required string RequiredField = 5;
}
}

11. usage of protobuf
test := &example.Test {
Label: proto.String("hello"),
Type: proto.Int32(17),
Optionalgroup: &example.Test_OptionalGroup {
RequiredField: proto.String("good bye"),
},
}
data, err := proto.Marshal(test)
if err != nil {
log.Fatal("marshaling error: ", err)
}

12. A few gotchas…
dbg_f("Awaiting writer...")
<-outWG
dbg_ln("done.")
////////////////
hostname := packet[start:end]

13. Bottom line
Go is lightweight and powerfull
Collections and memory made right
Concurrency made right
Software architecture made wonderful

14. bohdan@trotsenko.com.ua
http://trotsenko.com.ua
@modosansreves