Go is a programming language created at Google to address issues with slowness, clumsiness, and lack of scalability in other languages like C++ used at Google. Key goals in developing Go were to eliminate slowness in development, improve effectiveness, and maintain or improve scale. Go provides features like built-in concurrency and goroutines to help solve problems at Google involving large, distributed systems.

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Golang
M Dineshkumar
Software Developer

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History
 Design began in late 2007.
 Key players:
 Robert Griesemer, Rob Pike, Ken Thompson
 Later: Ian Lance Taylor, Russ Cox
 Became open source in November 2009.
 Developed entirely in the open; very active community.
 Language stable as of Go 1, early 2012.

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Go at Google
 Go is a programming language designed by Google to help
solve Google's problems.
 Google has big problems.

4. Big Hardware

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Big software
 C++ (mostly) for servers, plus lots of Java and Python
 thousands of engineers
 gazillions of lines of code
 distributed build system
 And of course:
 zillions of machines, which we treat as a modest number of
compute clusters
 Development at Google can be slow, often clumsy.

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The reason for Go
Goals:
 eliminate slowness
 eliminate clumsiness
 improve effectiveness
 maintain (even improve) scale
 Go was designed by and for people who write, read, debug and
maintain—large software systems.
 Go's purpose is not research into programming language design.
 Go's purpose is to make its designers' programming lives better.

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Who uses?

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What is Go?
Go is:
 open source
 concurrent
 garbage-collected
 efficient
 scalable
 simple
 fun
 boring (to some)
http://golang.org

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Compiler
 Go is a compiled language, and it has two main compilers, gc
and Gccgo.

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Purpose
 Efficient compilation
 Efficient execution
 Ease of programming.

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Go’s ancestors

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Golang's characteristics
 Goroutine
A Goroutine has a 2kB stack and grow by allocating and freeing
heap storage as required by the program. While threads in other
languages starts with 1MB of storage which is 500 times more than
the stack size of a goroutine.

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Golang's characteristics
 Concurrency
One of Golang's strongest characteristics is its concurrency.
Concurrency is often confused to be the same as parallelism.
Parallelism is to do many things at once, while concurrency is to
handle many things at once.

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Golang's characteristics
 Error handling
Many Go-users have been complaining about is how strict the
compiler is about unused variables and packages. The program
wont be compiled if one variable or package is unused forcing the
programmer to have tidy code and maximizing storage usage.

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Golang's characteristics
 Cgo
Go has a tool called cgo that makes it possible for programs written
in Go to call into C and C++ and in those programs the C or C++
can call back into Go. But there is no support for C or C++ to call
directly to go meaning this does not work for programs that starts
execution in C or C++.

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Golangs characteristics
 Generics
Generics is a subject that is well discussed in Go. This is something
that is not exactly supported because Go was designed with
simplicity in mind and generics was thought of to be too complex.
There is actually three generic data types in Golang:
Arrays
Slices
Maps

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Golangs characteristics
 Interfaces
Interfaces in Go works as interfaces in other programming
languages like for example Java, except that you can make use of
the empty interface in Go.

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Empty Interface

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Syntax and quirks
 Compilation
In most Go source code files, semicolons won’t be found. This is
because there is no need for the programmer to type them out
since the compiler parses the source code and inserts semicolons
on its own. This makes compilation a bit slower, but the code more
cleaner looking.

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 Functions
In Go multiple values of same type can be defined as "(x,y int)“.
This means that x and y are two inputs to the function add with the
type int. The text next to the input variables are the output or
returned values of the function. There is something called "naked
returns" in Golang, which is a return followed by nothing. This is
possible due to the naming of the returned value and it’s type in the
declaration of the function.

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 Pointers in Go
Since Go is built to resemble C and C++, the pointer syntax too is
very similar. A simple example would be seen in example. In the
example it can be seen how the value of the original structure can
be changed by the pointer without dereferencing the pointer.
For example, in C p->x is equivalent to (*p).x and in Golang the
dereferencing is not needed and simply p.x will give the wanted
result.

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Hello World Example
 A Go program basically consists of the following parts:
 Package Declaration
 Import Packages
 Functions
 Variables
 Statements and Expressions
 Comments

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Executing a Go Program
 Open a text editor and add the above-mentioned code.
 Save the file as hello.go
 Open the command prompt.
 Go to the directory where you saved the file.
 Type go run hello.go and press enter to run your code.
 If there are no errors in your code, then you will see "Hello
World!" printed on the screen.

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Leaning GO
 Types
 Variables
 Function
 Control Structure
 Object Oriented
 Concurrency

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Type
 Basic Type
 Boolean
 String
 Byte
 Float
 Constants

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Type
 Composite Type
 Arrays
 Slices
 Maps
 Structs
 JSONS
 Text and HTML template

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Variables

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Static Type Declaration in Go

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Dynamic Type Declaration

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Mixed Variable Declaration in Go

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Constants

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Arrays

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Slice

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Maps

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Pointers

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Control Structure

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Function

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Function

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Function

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Function

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Object Oriented
 Structs
 Methods
 Interfaces

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Struct

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Struct

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Struct

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Methods

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Interface

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Concurrency
 Goroutine
 Channel
 Select

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Goroutine

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Channel

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Channel

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Select
In Go language, the select statement is just like switch statement, but in the select
statement, case statement refers to communication, i.e. sent or receive operation on
the channel.

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