My notes on exercises a tour of Go.

MyFirstGo.md

Getting started My Go lang

see:

• Effective Go
• A Tour of Go
• Go lang doc
• go-wiki

env

MacOSX

Install

$ brew install go

$ go version

# for local go repository
$ mkdir ~/go

open .bashrc

#go lang
export GOROOT=`go env GOROOT`
export GOPATH=$HOME/go
export PATH=$PATH:$GOROOT/bin:$GOPATH/bin

Hello Go!

$ mkdir -p $GOPATH/src/github.com/rkaneko/hello

• $GOPATH/github.com/rkaneko/hello/hello.go

package main

import "fmt"

func main() {
    fmt.Printg("Hello, world.\n")    
}

$ cd $GOPATH/src

$ go run github.com/rkaneko/hello/hello.go
Hello, world.

go build/install

$ cd $GOPATH/src

$ go build github.com/rkaneko/hello

# If you want add hello binary to $GOPATH/bin, type under.
$ go install github.com/rkaneko/hello

$ tree $GOPATH
├── bin
│   └── hello
├── pkg
│   └── darwin_amd64
│       └── github.com
│           └── rkaneko
└── src
    └── github.com
        └── rkaneko
            ├── hello
                └── hello.go

$ hello
Hello, world.

testing

• $GOPATH/src/github.com/rkaneko/newmath/newmath_test.go

package newmath

import "testing"

func TestSqrt(t *testing.T) {
    const in, out = 4, 2
    if x := Sqrt(in); x != out {
        t.Error("Sqrt(%v) = %v, want %v", in, x, out)
    }
}

$ go test github.com/rkaneko/newmath
ok      github.com/rkaneko/newmath  0.021s

# see more information for testing
$ go help test

Utility for Vim

• nsf/gocode
• golint

TODO

• vim-go

vim-goがあればいらないかも

• vim-godef
• gotags

---

A tour of go

brand-new things for me

• (13) Short variable declarations
• (15) Type conversions (more simply)
  • Unlike in C, Go doesn't convert type implicitly.
• (30) The new funcion
• (36) Range
  • Iterate over a slice or map
• (42) How to see if map's key or value exists or not
• (49) Switch with no condition
  • convenient when u writes long if then else chains
• (52) Methods
  • put receiver between func keyword and method name
• (54) Methods with pointer receivers
• (57) Errors
• (63) strings.NewReader("some string"), io.Copy(os.Stdout, pointer of []byte)