Add signature help and current active parameter highlighting

README.md

@@ -155,6 +155,12 @@ Fill struct with gopls
 Treetsitter symbols in all buffers
 ![treesitter](https://github.com/ray-x/files/blob/master/img/navigator/treesitter.jpg?raw=true)
 
+### Signature help
+
+Improved signature help with current parameter highlighted
+
+![signature](https://github.com/ray-x/files/blob/master/img/navigator/signature_with_highlight.jpg?raw=true)
+
 ### Call hierarchy (incomming/outgoing)
 
 ![incomming](https://github.com/ray-x/files/blob/master/img/navigator/incomming.jpg?raw=true)

lua/navigator/lspclient/mapping.lua

@@ -136,6 +136,8 @@ function M.setup(user_opts)
   vim.lsp.handlers["textDocument/documentSymbol"] = require "navigator.symbols".document_symbol_handler
   vim.lsp.handlers["workspace/symbol"] = require "navigator.symbols".workspace_symbol_handler
   vim.lsp.handlers["textDocument/publishDiagnostics"] = require'navigator.diagnostics'.diagnostic_handler
+  vim.lsp.handlers["textDocument/publishDiagnostics"] = require'navigator.diagnostics'.diagnostic_handler
+  vim.lsp.handlers["textDocument/signatureHelp"] = require'navigator.signature'.signature_handler
 
   -- vim.lsp.handlers["textDocument/hover"]  = require 'navigator.hover'.hover_handler
 end

lua/navigator/signature.lua

@@ -0,0 +1,63 @@
+local gui = require "navigator.gui"
+local util = require "navigator.util"
+local log = util.log
+local partial = util.partial
+local lsphelper = require "navigator.lspwrapper"
+local cwd = vim.fn.getcwd(0)
+local M = {}
+
+local match_parameter = function(result)
+  local signatures = result.signatures
+  if #signatures < 1 then
+    return result
+  end
+
+  local signature = signatures[1]
+  local activeParameter = result.activeParameter or signature.activeParameter
+  if activeParameter == nil then
+    return result
+  end
+
+  if #signature.parameters < 2 or activeParameter + 1 > #signature.parameters then
+    return result
+  end
+
+  local nextParameter = signature.parameters[activeParameter + 1]
+
+  local label = signature.label
+  if type(nextParameter.label) == "table" then -- label = {2, 4} c style
+    local range = nextParameter.label
+    label =
+      label:sub(1, range[1]) ..
+      [[`]] .. label:sub(range[1] + 1, range[2]) .. [[`]] .. label:sub(range[2] + 1, #label + 1)
+    signature.label = label
+  else
+    if type(nextParameter.label) == "string" then -- label = 'par1 int'
+      local i, j = label:find(nextParameter.label, 1, true)
+      if i ~= nil then
+        label = label:sub(1, i - 1) .. [[`]] .. label:sub(i, j) .. [[`]] .. label:sub(j + 1, #label + 1)
+        signature.label = label
+      end
+    end
+  end
+end
+
+local function signature_handler(err, method, result, _, bufnr, config)
+  -- log(result)
+  if not (result and result.signatures and result.signatures[1]) then
+    return
+  end
+  match_parameter(result)
+  local lines = vim.lsp.util.convert_signature_help_to_markdown_lines(result)
+  if vim.tbl_isempty(lines) then
+    return
+  end
+  vim.lsp.util.focusable_preview(
+    method .. "lsp_signature",
+    function()
+      lines = vim.lsp.util.trim_empty_lines(lines)
+      return lines, vim.lsp.util.try_trim_markdown_code_blocks(lines)
+    end
+  )
+end
+return {signature_handler = signature_handler}