feat: Lsp implementation (#50)

* feat(providers.lsp): Add textDocument/implementation support

* Update README.md for LSP lists

Co-authored-by: Tom Praschan <praschan@mueller-elektronik.de>

README.md

@@ -10,6 +10,8 @@ A pretty list for showing diagnostics, references, telescope results, quickfix a
 * pretty list of:
   - LSP Diagnostics
   - LSP references
+  - LSP implementations
+  - LSP definitions
   - quickfix list
   - location list
   - [Telescope](https://github.com/nvim-telescope/telescope.nvim) search results

lua/trouble/providers/init.lua

@@ -9,6 +9,7 @@ M.providers = {
   lsp_workspace_diagnostics = lsp.diagnostics,
   lsp_document_diagnostics = lsp.diagnostics,
   lsp_references = lsp.references,
+  lsp_implementations = lsp.implementations,
   lsp_definitions = lsp.definitions,
   quickfix = qf.qflist,
   loclist = qf.loclist,

lua/trouble/providers/lsp.lua

@@ -34,6 +34,24 @@ function M.references(win, buf, cb, _options)
   end)
 end
 
+---@return Item[]
+function M.implementations(win, buf, cb, _options)
+  local method = "textDocument/implementation"
+  local params = util.make_position_params(win, buf)
+  params.context = { includeDeclaration = true }
+  lsp.buf_request(buf, method, params, function(err, _method, result, _client_id, _bufnr, _config)
+    if err then
+      util.error("an error happened getting implementation: " .. err)
+      return cb({})
+    end
+    if result == nil or #result == 0 then
+      return cb({})
+    end
+    local ret = util.locations_to_items({ result }, 0)
+    cb(ret)
+  end)
+end
+
 ---@return Item[]
 function M.definitions(win, buf, cb, _options)
   local method = "textDocument/definition"