lsp_signature.nvim

Show function signature when you type

This nvim plugin is made for completion plugins that do not support signature help. Need neovim-0.5+ and enable nvim-lsp.
Part of the code was ported from completion-nvim, which does have lots of cool features.
Fully asynchronous lsp buf request.
Virtual text available

Golang with markdown

Highlight with "Search"

signature2.mov

Lua

The plugin also re-write the builtin lsp signature allow the parameter highlight

Using virtual text to show the next parameter

Virtual text only mode

(from @fdioguardi)

Multiple signatures

In case some of the languages allow function overload, the plugin will show all available signatures

Install:

" dein
dein#add('ray-x/lsp_signature.nvim')

" plug
Plug 'ray-x/lsp_signature.nvim'

" Packer
use {
  "ray-x/lsp_signature.nvim",
}

Setup / Attach the plugin

In your init.lua, call setup()

cfg = {...}  -- add you config here
require "lsp_signature".setup(cfg)

Alternatively, call on_attach() when the LSP client attaches to a buffer

e.g. gopls:

local golang_setup = {
  on_attach = function(client, bufnr)
    ...
    require "lsp_signature".on_attach()  -- Note: add in lsp client on-attach
    ...
  end,
  ...
}

require'lspconfig'.gopls.setup(golang_setup)

Configure

Floating window borders

If you have a recent enough build of Neovim, you can configure borders in the signature help floating window(Thanks @Gabriel Sanches for the PR):

local example_setup = {
  on_attach = function(client, bufnr)
    ...
    require "lsp_signature".on_attach({
      bind = true, -- This is mandatory, otherwise border config won't get registered.
      handler_opts = {
        border = "rounded"
      }
    }, bufnr)
    ...
  end,
  ...
}

Or:

  require'lspconfig'.gopls.setup()
  require "lsp_signature".setup({
    bind = true, -- This is mandatory, otherwise border config won't get registered.
    handler_opts = {
      border = "rounded"
    }
  })

Full configuration (with default values)

 cfg = {
  debug = false, -- set to true to enable debug logging
  log_path = vim.fn.stdpath("cache") .. "/lsp_signature.log", -- log dir when debug is on
  -- default is  ~/.cache/nvim/lsp_signature.log
  verbose = false, -- show debug line number

  bind = true, -- This is mandatory, otherwise border config won't get registered.
               -- If you want to hook lspsaga or other signature handler, pls set to false
  doc_lines = 10, -- will show two lines of comment/doc(if there are more than two lines in doc, will be truncated);
                 -- set to 0 if you DO NOT want any API comments be shown
                 -- This setting only take effect in insert mode, it does not affect signature help in normal
                 -- mode, 10 by default

  floating_window = true, -- show hint in a floating window, set to false for virtual text only mode

  floating_window_above_cur_line = true, -- try to place the floating above the current line when possible Note:
  -- will set to true when fully tested, set to false will use whichever side has more space
  -- this setting will be helpful if you do not want the PUM and floating win overlap

  floating_window_off_x = 1, -- adjust float windows x position.
  floating_window_off_y = 1, -- adjust float windows y position.


  fix_pos = false,  -- set to true, the floating window will not auto-close until finish all parameters
  hint_enable = true, -- virtual hint enable
  hint_prefix = "🐼 ",  -- Panda for parameter
  hint_scheme = "String",
  hi_parameter = "LspSignatureActiveParameter", -- how your parameter will be highlight
  max_height = 12, -- max height of signature floating_window, if content is more than max_height, you can scroll down
                   -- to view the hiding contents
  max_width = 80, -- max_width of signature floating_window, line will be wrapped if exceed max_width
  handler_opts = {
    border = "rounded"   -- double, rounded, single, shadow, none
  },

  always_trigger = false, -- sometime show signature on new line or in middle of parameter can be confusing, set it to false for #58

  auto_close_after = nil, -- autoclose signature float win after x sec, disabled if nil.
  extra_trigger_chars = {}, -- Array of extra characters that will trigger signature completion, e.g., {"(", ","}
  zindex = 200, -- by default it will be on top of all floating windows, set to <= 50 send it to bottom

  padding = '', -- character to pad on left and right of signature can be ' ', or '|'  etc

  transparency = nil, -- disabled by default, allow floating win transparent value 1~100
  shadow_blend = 36, -- if you using shadow as border use this set the opacity
  shadow_guibg = 'Black', -- if you using shadow as border use this set the color e.g. 'Green' or '#121315'
  timer_interval = 200, -- default timer check interval set to lower value if you want to reduce latency
  toggle_key = nil -- toggle signature on and off in insert mode,  e.g. toggle_key = '<M-x>'
}

-- recommended:
require'lsp_signature'.setup(cfg) -- no need to specify bufnr if you don't use toggle_key

-- You can also do this inside lsp on_attach
-- note: on_attach deprecated
require'lsp_signature'.on_attach(cfg, bufnr) -- no need to specify bufnr if you don't use toggle_key

Signature in status line

Sample config

API

require("lsp_signature").status_line(max_width)

return a table

{
  label = 'func fun_name(arg1, arg2...)'
  hint = 'arg2'
}

local current_signature = function(width)
  if not packer_plugins["lsp_signature.nvim"] or packer_plugins["lsp_signature.nvim"].loaded == false then
    return ""
  end
  local sig = require("lsp_signature").status_line(width)
  return sig.label .. "🐼" .. sig.hint
end

Should signature floating windows fixed

fix_pos can be a function, it took two element, first is the signature result for your signature, second is lsp client.

You can provide a function.

e.g.

fix_pos = function(signatures, lspclient)
   if signatures[1].activeParameter >= 0 and #signatures[1].parameters == 1 then
     return false
   end
   if lspclient.name == 'sumneko_lua' then
     return true
   end
   return false
end

Sample config with cmp, luasnipet and autopair

init.lua

Q&A:

Q: What is the default colorscheme in screenshot:

A: aurora

Q: I can not see border after enable border = "single"/"rounded"

A: Try another colorscheme (e.g. colorscheme aurora, or colorscheme luna). If issue persists, please submit an issue

Q: It is not working 😡

A: Here is some trouble shooting: ray-x#1

If you are using JDTLS, please read this: issue #97

Q:I do not like the pop window background highlight, how to change it?

A: Redefine your NormalFloat and FloatBorder, esp if your colorscheme dose not define it.

Q: How to change parameter highlight

A: By default, the highlight is using "LspSignatureActiveParameter" defined in your colorscheme, you can either override "LspSignatureActiveParameter" or define, e.g. use IncSearch setup({ hi_parameter = "IncSearch"})

Q: I can not see 🐼 in virtual text

A: It is emoji, not nerdfont. Please check how to enable emoji for your terminal.

Q: Working with cmp/coq. The floating windows block cmp/coq

A: A few options here, z-index, floating_window_above_cur_line, floating_window_off_x/y, toggle_key. You can find the best setup for your workflow.

abzcoding / lsp_signature.nvim