go.nvim/README.md

# [WIP] go.nvim

A modern golang neovim plugin based on treesitter and nvim-lsp. It is written in Lua and async as much as possible.
PR & Suggestions welcome.
The plugin covers most features required for a gopher.

- Syntex highlight & Texobject: Native treesitter support is faster and more accurate. All you need is a theme support treesitter, try
  [aurora](https://github.com/ray-x/aurora). Also, there are quite a few listed in [awesome-neovim](https://github.com/rockerBOO/awesome-neovim)
- GoToXxx: E.g reference, implementaion, definition, goto doc, peek code/doc etc. You need lspconfig setup. There are lots of posts on how to
  set it up. You can also check my vimrc [lspconfig.lua](https://github.com/ray-x/dotfiles/blob/master/nvim/lua/modules/completion/lspconfig.lua)
- Runtime lint/vet/compile: Supported by lsp (once you setup up you lsp client), GoLint with golangci-lint alo supported
- Build/Make/Test: Go.nvim provides supports for these by an async job wrapper.
- Unit test: Support [gotests](https://github.com/cweill/gotests)
- tag modify: Supports gomodifytags
- Code format: Supports LSP format and GoFmt
- Comments: Add autodocument for your package/function/struct/interface. This feature is unique and can help you suppress golint
  errors...

## install

add 'ray-x/go.nvim' to your package manager, the depency is `treesitter` (and optionally, treesitter-objects)
related binaries will be installed the first time you using it
Add lsp format in your vimrc. [You can check my dotfiles for details](https://github.com/ray-x/dotfiles/blob/edc97a85e2a12cfcfc9765d28e63863e9926e321/nvim/lua/modules/completion/lspconfig.lua#L345-L390)

To startup/setup the plugin

```lua
require('go').setup()
```

## code format

nvim-lsp support goimport by default.

```vim
autocmd BufWritePre (InsertLeave?) <buffer> lua vim.lsp.buf.formatting_sync(nil,500)
```

The plugin provides code format, by default is goline + gofumports (stricter version of goimport)

The format tool is a asyn format tool in format.lua

```lua
require("go.format").gofmt()
require("go.format").goimport()
```

## Textobject

Supported by treesitter. TS provided better parse result compared to regular expression.
Check [my treesitter config file](https://github.com/ray-x/dotfiles/blob/master/nvim/lua/modules/lang/treesitter.lua) on how to setup
textobjects. Also with treesitter-objects, you can move, swap select block of code which is fast and accurate.

## Build and test

Provided wrapper for gobulild/test etc with async make

## Unit test with [gotests](https://github.com/cweill/gotests) and testify

Support table based unit test auto generate, parse current function/method name using treesitter

## Modifytags

Modify struct tags by [`gomodifytags`](https://github.com/fatih/gomodifytags) and treesitter

## GoFmt

nvim-lsp support goimport by default. The plugin provided a new formatter, goline + gofumports (stricter version of
goimport)

## Comments and Doc

Auto doc (to suppress golang-lint warning), generate comments by treesitter parsing result

```go
type GoLintComplaining struct{}
```

And run

```lua
 lua.require('go.comment').gen() -- or your faviourite key binding and setup placeholder "no more complaint ;P"
```

The code will be:

```go
// GoLintComplaining struct no more complaint ;P
type GoLintComplaining struct{}
```

## LSP

LSP supported by nvim-lsp is good enough for a gopher. If you looking for a better GUI. lspsaga or and lsp-utils are
what you are looking for.

## Lint

Supported by LSP, also GoLint command (by calling golangcl-lint) if you need background golangci-lint check, you can
configure it with ALE

## configuration

lua suggested:

```lua
require('go').setup(cfg = {
  goimport='gofumports', -- g:go_nvim_goimport
  gofmt = 'gofumpt', --g:go_nvim_gofmt,
  max_len = 120, -- g:go_nvim_max_len
  transform = false, -- vim.g.go_nvim_tag_transfer  check gomodifytags for details
  test_template = '', -- default to testify if not set; g:go_nvim_tests_template  check gotests for details
  test_template_dir = '', -- default to nil if not set; g:go_nvim_tests_template_dir  check gotests for details
  comment_placeholder = '' ,  -- vim.g.go_nvim_comment_placeholder your cool placeholder e.g. ﳑ       
  verbose = false,  -- output loginf in messages
})
```

You will need to add keybind yourself:
e.g

```lua
  vim.cmd("autocmd FileType go nmap <Leader><Leader>l GoLint")
  vim.cmd("autocmd FileType go nmap <Leader>gc :lua require('go.comment').gen()")

```

## Nvim LSP setup

For golang, the default gopls setup works perfect fine, Also you can check [My LSP config URL](https://github.com/ray-x/dotfiles/blob/c45c1a79962e6cce444b1375082df03a88fa6054/nvim/lua/modules/completion/lspconfig.lua#L252).

And also to diagnostic issue, you can use the default setup. If you want to put **all** diag error/warning of your project in quickfix, you can do this

```lua
  -- hdlr alternatively, use lua vim.lsp.diagnostic.set_loclist({open_loclist = false})  -- true to open loclist
  local diag_hdlr =  function(err, method, result, client_id, bufnr, config)
    -- vim.lsp.diagnostic.clear(vim.fn.bufnr(), client.id, nil, nil)
    vim.lsp.diagnostic.on_publish_diagnostics(err, method, result, client_id, bufnr, config)
    if result and result.diagnostics then
        local item_list = {}
        local s = result.uri
        local fname = s
        for _, v in ipairs(result.diagnostics) do
            i, j = string.find(s, "file://")
            if j then
              fname = string.sub(s, j + 1)
            end
            table.insert(item_list, { filename = fname, lnum = v.range.start.line + 1, col = v.range.start.character + 1; text = v.message; })
        end
        local old_items = vim.fn.getqflist()
        for _, old_item in ipairs(old_items) do
            local bufnr = vim.uri_to_bufnr(result.uri)
            if vim.uri_from_bufnr(old_item.bufnr) ~= result.uri then
                    table.insert(item_list, old_item)
            end
        end
        vim.fn.setqflist({}, ' ', { title = 'LSP'; items = item_list; })
      end
    end


  vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(
    diag_hdlr,
    {
      -- Enable underline, use default values
      underline = true,
      -- Enable virtual text, override spacing to 0
      virtual_text = {
        spacing = 0,
        prefix = '', --'',  
      },
      -- Use a function to dynamically turn signs off
      -- and on, using buffer local variables
      signs = true,
      -- Disable a feature
      update_in_insert = false,
    }
  )
```