deepak / learn_go

Learn Go lang. examples and a README

Notes

Installed using homebrew

brew install go --cross-compile-common

Did not need to set $GOROOT It is only a convention http://golang.org/doc/install#gopath

Code installed with homebrew have their bins in PATH so that was also not needed

mercurial (hg) is needed for go get might use svn, hg, git or bzr where is this config set in packages ? https://code.google.com/p/go-wiki/wiki/GoGetTools

go get code.google.com/p/go-tour/gotour go: missing Mercurial command. See http://golang.org/s/gogetcmd package code.google.com/p/go-tour/gotour: exec: "hg": executable file not found in $PATH

GOPATH

http://golang.org/doc/code.html#GOPATH

GOPATH is where downloaded code is installed

If GOPATH is not set:

go get code.google.com/p/go-tour/gotour package code.google.com/p/go-tour/gotour: cannot download, $GOPATH not set. For more details see: go help gopath

Can set GOPATH to

export GOPATH="/usr/local/var/go"

CHECK: It can be colon seperated if multiple paths are to be specified

emacs setup

install go-mode

REPL

seems like go does not provide a shell, even though there is a sandbox on the website http://stackoverflow.com/questions/8513609/does-go-provide-repl https://groups.google.com/forum/#!topic/golang-nuts/0o6sBNl1abY

Missing Ruby

1. REPL
2. begin-end blocks

Explicit erorr checks also seem like line-noise but have to try splitting code into smaller functions

terminology

• packages
• functions take parameters

Folder structure for packages

TODO: http://golang.org/doc/code.html#PackagePaths

Running Go Programs

go run hello.go

package manager aka rubygems ?

warnings

importing a package but not using it will throw a warning TODO: automatically collect a list of such warnings in a csv. maybe driven via tests

list of community code

installing code (go get)

comparisons with Ruby

no implicit returns like ruby semicolons can be used as terminators. but is not necessary

Questions

Programs start running in package main.

import ( "fmt" "math" ) fmt.Println("Happy", math.Pi, "Day") like a ruby module function. not like include ie. still has seperate namespace

By convention, the package name is the same as the last element of the import path.

List names exported by a package

After importing a package, you can refer to the names it exports. In Go, a name is exported if it begins with a capital letter. Foo is an exported name, as is FOO. The name foo is not exported.

func add(x int, y int) int { } to define a function. why not keep it like c ? TODO: read http://golang.org/doc/articles/gos_declaration_syntax.html

emacs mode for go ?

import ( "fmt" "math" ) what internal data-structure is that ?

TDD in go. what is the culture regarding tests in the community ?

how to find type of a variable ? and list of types in golang reflection in go. variables/types in current scope ? any type for "result parameter" in http://tour.golang.org/#9

what is := a, b := swap("hello", "world")

return_all.go: do not care about unused variables otherwise program does not run