Hello Go

Let’s write a hello world programme in go

package main

import "fmt"

func main() {
    fmt.Println("hello world")
}

In Go, you don’t manually need to write or remove import statements yourself. As soon as we save the code, Go automatically manages the package imports required in the code.

Command to Run the Go File

go run <file_name>

This command will only execute the code. It will not generate any executable (.exec) files that can be executed separately.

Go Docs and GOPATH

• go help

  Lists all the commands available for Go.

• go help <command_name>

  Provides details about a specific command.

• GOPATH

  The Go path is used to resolve import statements and is implemented by and documented in the go/build package.

  If the environment variable is unset, GOPATH defaults to a subdirectory named "go" in the user's home directory ($HOME/go on Unix, %USERPROFILE%\\\\go on Windows), unless that directory holds a Go distribution. Run go env GOPATH (case-sensitive) to see the current GOPATH.

  You can see various packages inside the /pkg/mod directory of GOPATH.

• 

The Semicolon Rule

In Go, like C, the formal grammar uses semicolons to terminate statements, but unlike in C, those semicolons do not appear in the source code. Instead, the lexer uses a simple rule to insert semicolons automatically as it scans, so the input text is mostly free of them. The lexer always inserts a semicolon after the token.

• What is a Lexer?

A lexer, also known as a scanner or tokenizer, breaks up the source code into meaningful tokens. It is the first phase of a compiler or interpreter.