Add go configuration to vim

added vim-go plugin and assorted mappings for tests, navigation, running
and documenting go files

.config/nvim/init.vim

@@ -62,6 +62,8 @@ Plug 'dyng/ctrlsf.vim'
 Plug 'sheerun/vim-polyglot' " syntax plugins for almost every language
 Plug 'stephpy/vim-yaml'
 Plug 'mhartington/nvim-typescript', {'for': 'typescript','do': './install.sh'}
+Plug 'fatih/vim-go', { 'do': ':GoUpdateBinaries' }
+Plug 'deoplete-plugins/deoplete-go', { 'do': 'make'}
 
 " HTML Workflow
 Plug 'valloric/matchtagalways', { 'on': [] }
@@ -84,13 +86,15 @@ Plug 'lervag/wiki.vim'
 
 " For async completion
 Plug 'Shougo/deoplete.nvim', { 'on': [] } " automatic suggestions, can also perhaps be changed for newer plugs
+Plug 'Shougo/echodoc.vim', { 'on': [] }
 Plug 'w0rp/ale', { 'on': [] } " asynchronous linting - might be superseded by lsp or coc.nvim at some point
 " lazy loading since they require a lot of startup time
 augroup load_ide_features
   autocmd!
-  autocmd InsertEnter * call plug#load('ale', 'deoplete.nvim')
+  autocmd InsertEnter * call plug#load('ale', 'deoplete.nvim', 'echodoc.vim')
                      \| autocmd! load_ide_features
   autocmd InsertEnter * call deoplete#enable()
+  autocmd InsertEnter * call echodoc#enable()
 augroup END
 
 " Design
@@ -99,9 +103,8 @@ Plug 'vim-airline/vim-airline-themes'
 Plug 'edkolev/tmuxline.vim'
 
 " Colorschemes
-Plug 'Nequo/vim-allomancer'
 Plug 'morhetz/gruvbox'
-Plug 'nightsense/snow'
+Plug 'rakr/vim-one'
 
 call plug#end()
 endif
@@ -212,6 +215,33 @@ endfunction
 autocmd! User GoyoEnter nested call <SID>goyo_enter()
 autocmd! User GoyoLeave nested call <SID>goyo_leave()
 
+" PLUGIN: vim-go
+" change the tabstops for go to use tabs and a width of 4
+" this conforms with the gofmt expectations
+au FileType go set noexpandtab
+au FileType go set shiftwidth=4
+au FileType go set softtabstop=4
+au FileType go set tabstop=4
+" enable all sorts of highlighting options for
+" variables/functions/arguments...
+let g:go_highlight_build_constraints = 1
+let g:go_highlight_extra_types = 1
+let g:go_highlight_fields = 1
+let g:go_highlight_functions = 1
+let g:go_highlight_methods = 1
+let g:go_highlight_operators = 1
+let g:go_highlight_structs = 1
+let g:go_highlight_types = 1
+" enable highlighting of other uses of the same variable
+let g:go_auto_sameids = 1
+" automatically import needed dependencies
+" TODO do I need this? not doing it automatically does lead to more conscious
+" decision making on imports
+let g:go_fmt_command = "goimports"
+" show type information for variables in the status line
+let g:go_auto_type_info = 1
+
+
 " PLUGIN: DEOPLETE
 " enable deoplete at startup
 let g:deoplete#enable_at_startup = 0
@@ -222,8 +252,20 @@ let g:deoplete#enable_refresh_always = 1
 let g:deoplete#max_abbr_width = 0
 let g:deoplete#max_menu_width = 0
 let g:deoplete#omni#input_patterns = get(g:,'deoplete#omni#input_patterns',{})
+" PLUGIN: ECHODOC
+let g:echodoc#type="virtual"
+set splitbelow
+set completeopt+=menuone,noinsert,noselect
+set completeopt-=preview
+autocmd CompleteDone * pclose
 
 " PLUGIN: ALE
+" clearer Error and warning signs for the gutter
+let g:ale_sign_error = '⤫'
+let g:ale_sign_warning = '⚠'
+" Enable integration with airline.
+let g:airline#extensions#ale#enabled = 1
+
 let g:ale_fix_on_save = 1
 let g:ale_fixers = {
       \'javascipt': ['eslint', 'prettier'],
@@ -231,6 +273,9 @@ let g:ale_fixers = {
       \'typescript': ['prettier','tslint'],
       \'*': ['remove_trailing_lines', 'trim_whitespace'],
       \}
+let g:ale_linters = {
+      \ 'go': ['gopls'],
+      \}
 
 " PLUGIN: AIRLINE
 " PLUGIN: TMUXLINE
@@ -368,6 +413,23 @@ nnoremap <leader><C-e> :NERDTreeVCS<CR>
 " open current nerdtree with current file highlighted
 nnoremap <leader>E :NERDTreeFind<CR>
 
+" vim-go mappings - will only activate in go files
+" most of this credit to https://hackernoon.com/my-neovim-setup-for-go-7f7b6e805876
+" switch between test file and function
+au Filetype go nnoremap <leader>ga <Plug>(go-alternate-edit)
+" switch between test file and function - in a horizontal/vertical split
+au Filetype go nnoremap <leader>gah <Plug>(go-alternate-split)
+au Filetype go nnoremap <leader>gav <Plug>(go-alternate-vertical)
+" run a test (but run it as short version, in case tests are tagged
+" accordingly)
+au FileType go nnoremap <F10> :GoTest -short<cr>
+" show/hide code coverage of go file
+au FileType go nnoremap <F9> :GoCoverageToggle -short<cr>
+" To get the documentation of whatever you are hovering over press K (to go
+" back C-t) -- this is enabled by default and needs no bind
+" go to the definition of whatever you hover over
+au FileType go nnoremap <F12> <Plug>(go-def)
+
 " Call leaderf with <leader-f> (necessary to enable leaderf lazyloading)
 nnoremap <leader>F :LeaderfFile<cr>
 nnoremap <leader>f :LeaderfBuffer<cr>