Overview of Golang

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Golang EMC Dojo
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play.golang.org
github.com/kaleo211/golang-demo

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Origins
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❖ Created at Google in 2007
❖ Open Source in 2009
❖ First stable release in 2012
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❖ C: syntax, control-flow, basic data types, call by value,
pointers
❖ Oberon-2: packages, imports, method declarations
❖ Alef: concurrency, channel, garbage collection
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package main
/*
#include <stdio.h>
#include <stdlib.h>
void myprint(char* s) {
printf("%sn", s);
}
*/
import "C"
import "unsafe"
func main() {
cs := C.CString("Hello from stdion")
C.myprint(cs)
C.free(unsafe.Pointer(cs))
}

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TIOBE for June 2016
Position Language Ratings
1 Java 20.794%
2 C 12.376%
3 C++ 6.199%
4 Python 3.900%
40 Go 0.209%
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Why Go?

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Fast Compilation
Easy for OOP
Built-in Concurrency
Pass by Reference
Readability
Dependency Management

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Fast Compilation
Easy for OOP
Built-in Concurrency
Pass by Reference
Readability
Dependency Management

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“Go provides a model for software construction that
makes dependency analysis easy and avoids much of
the overhead of C-style include files and libraries.”

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Fast Compilation
Easy for OOP
Built-in Concurrency
Pass by Reference
Readability
Dependency Management

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“If you could do Java over again,
what would you change?”

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“The real problem wasn't classes, but rather
implementation inheritance.”
“I’d leave out classes.”

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Is-a vs Has-a
Prius is a car that has the ability to run
Peter has the ability to run
Peter is a human that has the ability to run

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Duck Typing
“If it looks like a duck and quacks like a duck,
it’s a duck.”

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Fast Compilation
Easy for OOP
Built-in Concurrency
Pass by Reference
Readability
Dependency Management

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Concurrency vs Parallelism
Dealing with things at once Doing things at once
Core0
Core1
Core0

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Goroutines vs Thread
The OS schedules threads to run against available processors
Go runtime schedules goroutines to run within a logical
processor that is bound to a single OS thread

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Go 1.6.2 (April 2016)
64-bit x86 CPU (A10-7850K 4GHz)
| Number of goroutines: 100,000
| Per goroutine:
| Memory: 4707.92 bytes
| Time: 1.842097 µs

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Fast Compilation
Easy for OOP
Built-in Concurrency
Pass by Reference
Readability
Dependency Management

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Pass by Value vs Pass by Reference
Performance

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Pointer Arithmetic
Memory allocation
Segment Error

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Fast Compilation
Easy for OOP
Built-in Concurrency
Pass by Reference
Readability
Dependency Management

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60+ companies
3,000,000 lines

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VS

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go fmt

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Fast Compilation
Easy for OOP
Built-in Concurrency
Pass by Reference
Readability
Dependency Management

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gocode
├── bin
├── pkg
└── src
├── github.com
│ ├── Sirupsen
│ │ └── logrus
│ ├── kaleo211
│ │ └── golang-demo
│ └── kisielk
│ ├── errcheck
│ └── gotool
└── golang.org
└── x
├── net
└── oauth2

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go get github.com/kaleo211/golang-demo