Getting Started with Golang and Vim

Watch on YouTube: youtu.be/Gen2OXG-3f8

Things we need to talk about.

vim-go
gofmt
goimport
golint
gocode
godef

Other great resources

Rant/Rave

Go is beautiful in that it doesn't leave any room for bickering, bikeshiding, or otherwise b... complaining about stupid stuff that doesn't matter - like spacing, tabs, semicolons, etc.

If you're going to contribute code (or write code) without looking like an idiot, you need to have gofmt run everytime you save a Go file so that it will automatically convert your spaces and such.

Unfortunately, vim isn't so lucky. There used to be one standard plugin manager for vim: pathogen. Now there are 3 or 4 of them and there's nothing really different about them except that using one or the other will make you feel more or less elitist than someone who has a stronger or weaker opinion than you that's different from yours.

Because I'm not an elitist and I haven't seen any technical or cultural advantage to the other loaders, we're still going to use pathogen, which works awesomely.

Is Go correctly installed?

Try these and see what you get

go version
> go version go1.4.2 darwin/amd64

And also

echo $GOPATH
> /Users/aj/Code/go

If either of those don't work, please see Getting Started with Go before going any further.

Do you have the latest vim?

If you're not too familiar with vim yet, I'd also recommend Vim for people who would rather not use Vim.

Don't use the version bundled with OS X.

I honestly don't remember why, but I remember some tool I was using needed features from the newest version (which is super-easy to install).

brew update
brew install vim

> vim-7.4.712

If you get an error about not having brew just run this (and then go back and rerun that):

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

You're Ready for vim + Go!

You will need the generic vim-for-coders modules and then a few go specific tweaks.

generic vim setup

pathogen
vim-sensible
syntastic

To have a "this doesn't suck" experience with vim you need to install pathogen (the vim package manager), so that you can install vim-sensible.

To have a "this is awesome" experience with vim you need to install syntastic (code highlighting and is-it-broke checker tool) to start with, and you'll add other stuff specific to language xyz and whatnot as you go.

So, from the top, in case you haven't done this before:

# Install pathogen
mkdir -p ~/.vim/autoload ~/.vim/bundle && \
curl -LSso ~/.vim/autoload/pathogen.vim https://tpo.pe/pathogen.vim

# Install vim-sensible
git clone git://github.com/tpope/vim-sensible.git ~/.vim/bundle/vim-sensible

# Install syntastic
git clone https://github.com/scrooloose/syntastic.git ~/.vim/bundle/syntastic

Now you need to turn pathogen, which enables all of the other modules to load automatically. You'll also need on and tell syntastic

vim ~/.vimrc

" plugins expect bash - not fish, zsh, etc
set shell=bash

" which key should be the <leader>
" (\ is the default, but ',' is more common, and easier to reach)
let mapleader=","

" pathogen will load the other modules
execute pathogen#infect()

" we want to tell the syntastic module when to run
" we want to see code highlighting and checks when  we open a file
" but we don't care so much that it reruns when we close the file
let g:syntastic_check_on_open = 1
let g:syntastic_check_on_wq = 0

" we also want to get rid of accidental trailing whitespace on save
autocmd BufWritePre * :%s/\s\+$//e

" tell vim to allow you to copy between files, remember your cursor
" position and other little nice things like that
set viminfo='100,\"2500,:200,%,n~/.viminfo

Go Stuff

Now there are tons of cool things you can do and add and whatnot, but I'm a lame-O, so I'm just presenting you with the most common ones that 90% of people use, not the esoteric, elite, or really fun ones.

First you just need to install go tools that aren't included in the standard install, but are super convenient:

# goimports
go get -u golang.org/x/tools/cmd/goimports

# gocode
go get -u github.com/nsf/gocode

# godef
go get -u github.com/rogpeppe/godef

# golint
go get -u github.com/golang/lint/golint

# errcheck
go get -u github.com/kisielk/errcheck

# oracle
go get -u golang.org/x/tools/cmd/oracle

All of them automatically install to $GOPATH/bin/, which is /Users/aj/Code/go/bin/ in my case.

If any of them didn't install there you could manually put them there with go build - like this: go build -o "$GOPATH/bin/" golang.org/x/tools/cmd/goimports

Tying vim + Go together

vim-go is the module that ties vim and go and all those go tools together is perfect unity.

You install it like so:

# Install vim-go
git clone https://github.com/fatih/vim-go.git ~/.vim/bundle/vim-go

# Install YouCompleteMe (requires building)
git clone https://github.com/Valloric/YouCompleteMe.git ~/.vim/bundle/YouCompleteMe

# the build step
brew install cmake
pushd ~/.vim/bundle/YouCompleteMe
git submodule update --init --recursive
./install.sh
popd

And then you need to make a minor edit to your vim config to tell vim-go that you have, in fact, installed goimports.

You can add this to the bottom of the file - or anywhere as long as it comes after execute pathogen#infect.

vim ~/.vimrc

" use goimports for formatting
let g:go_fmt_command = "goimports"

" turn highlighting on
let g:go_highlight_functions = 1
let g:go_highlight_methods = 1
let g:go_highlight_structs = 1
let g:go_highlight_operators = 1
let g:go_highlight_build_constraints = 1

let g:syntastic_go_checkers = ['go', 'golint', 'errcheck']

" Open go doc in vertical window, horizontal, or tab
au Filetype go nnoremap <leader>v :vsp <CR>:exe "GoDef" <CR>
au Filetype go nnoremap <leader>s :sp <CR>:exe "GoDef"<CR>
au Filetype go nnoremap <leader>t :tab split <CR>:exe "GoDef"<CR>

Celebrate

That's about it. Nothing too fancy and now you code in golang faster and you can contribute to go code without looking like a noob.

So SLOW!!!

If you find that vim begins to crawl you can always delete plugins from ~/.vim/bundle/ and and limit the number of syntax checkers in ~/.vimrc.

rm -rf ~/.vim/bundle/YouCompleteMe/

let g:syntastic_go_checkers = ['golint']