Sunday 18 October 2015

HB Blog 98: Go Programming Language - Google's Open Source Project.

Go, also commonly referred to as golang, is a programming language, an open source project developed at Google. It is expressive, concise, clean, and efficient. Its concurrency mechanisms make it easy to write programs that get the most out of multicore and networked machines, while its novel type system enables flexible and modular program construction. Go compiles quickly to machine code yet has the convenience of garbage collection and the power of run-time reflection. It's a fast, statically typed, compiled language that feels like a dynamically typed, interpreted language.
Go was born out of frustration with existing languages and environments for systems programming. Programming had become too difficult and the choice of languages was partly to blame. One had to choose either efficient compilation, efficient execution, or ease of programming; all three were not available in the same mainstream language. Programmers who could were choosing ease over safety and efficiency by moving to dynamically typed languages such as Python and JavaScript rather than C++ or, to a lesser extent, Java.

Go is an attempt to combine the ease of programming of an interpreted, dynamically typed language with the efficiency and safety of a statically typed, compiled language. It also aims to be modern, with support for networked and multicore computing. Finally, it is intended to be fast: it should take at most a few seconds to build a large executable on a single computer. To meet these goals required addressing a number of linguistic issues: an expressive but lightweight type system; concurrency and garbage collection; rigid dependency specification; and so on. These cannot be addressed well by libraries or tools; a new language was called for.

It is a statically-typed language with syntax loosely derived from that of C, adding garbage collection, type safety, some dynamic-typing capabilities, additional built-in types such as variable-length arrays and key-value maps, and a large standard library. Although it borrows ideas from existing languages, it has unusual properties that make effective Go programs different in character from programs written in its relatives. A straightforward translation of a C++ or Java program into Go is unlikely to produce a satisfactory result—Java programs are written in Java, not Go. On the other hand, thinking about the problem from a Go perspective could produce a successful but quite different program. In other words, to write Go well, it's important to understand its properties and idioms. It's also important to know the established conventions for programming in Go, such as naming, formatting, program construction, and so on, so that programs you write will be easy for other Go programmers to understand.
Refer below link to download the Go distribution:-
https://golang.org/dl/

Project structure:-
 Go code must be kept inside a workspace. A workspace is a directory hierarchy with three directories at its root:
    src contains Go source files organized into packages (one package per directory),
    pkg contains package objects, and
    bin contains executable commands.

The go tool builds source packages and installs the resulting binaries to the pkg and bin directories.
The src subdirectory typically contains multiple version control repositories (such as for Git or Mercurial) that track the development of one or more source packages.

To give an idea of how a workspace looks in practice, here's an example:

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


This workspace contains one repository (example) comprising two commands (hello and outyet) and one library (stringutil).
A typical workspace would contain many source repositories containing many packages and commands.
Commands and libraries are built from different kinds of source packages.

Check that Go is installed correctly by building a simple program, as follows.
Create a file named hello.go and put the following program in it:
package main
import "fmt"
func main() {
    fmt.Printf("hello, world\n")
}

Then run it with the go tool:
$ go run hello.go
hello, world

If you see the "hello, world" message then your Go installation is working.

An interactive introduction to Go in three sections. The first section covers basic syntax and data structures; the second discusses methods and interfaces; and the third introduces Go's concurrency primitives. Each section concludes with a few exercises so you can practice what you've learned.
Refer below link to download the Go distribution:-
https://tour.golang.org/

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