feat(symbols): "locate" current symbol (closes #2190)

Disabled by default, to use:
```lua
:FzfLua lsp_document_symbols locate=true
```

Author: ibhagwan

README.md

@@ -1233,6 +1233,7 @@ previewers = {
     symbols = {
         -- lsp_query      = "foo"       -- query passed to the LSP directly
         -- query          = "bar"       -- query passed to fzf prompt for fuzzy matching
+        locate            = false,      -- attempt to position cursor at current symbol
         async_or_timeout  = true,       -- symbols are async by default
         symbol_style      = 1,          -- style for document/workspace symbols
                                         -- false: disable,    1: icon+kind

lua/fzf-lua/config.lua

@@ -929,6 +929,15 @@ function M.normalize_opts(opts, globals, __resume_key)
     opts.fn_preprocess = [[return require("fzf-lua.make_entry").preprocess]]
   end
 
+  if opts.locate and utils.has(opts, "fzf", { 0, 36 }) then
+    table.insert(opts._fzf_cli_args, "--bind=" .. libuv.shellescape("load:+transform:"
+      .. FzfLua.shell.stringify_data(function(_, _, _)
+        if opts.__locate_pos then
+          return string.format("pos(%d)", opts.__locate_pos)
+        end
+      end, opts)))
+  end
+
   if opts.line_query and not utils.has(opts, "fzf", { 0, 59 }) then
     utils.warn("'line_query' requires fzf >= 0.59, ignoring.")
   elseif opts.line_query then

lua/fzf-lua/defaults.lua

@@ -362,6 +362,9 @@ M.defaults.files                = {
 
 M.defaults.global               = vim.tbl_deep_extend("force", M.defaults.files, {
   silent            = true,
+  -- TODO: lsp_workspace_symbols locate, not working yet
+  -- as opts.__locate_pos is inside the symbols picker opts
+  -- locate            = true,
   cwd_prompt        = true,
   line_query        = true,
   pickers           = function()
@@ -953,6 +956,7 @@ M.defaults.lsp                  = {
 
 M.defaults.lsp.symbols          = {
   previewer        = M._default_previewer_fn,
+  locate           = false,
   file_icons       = 1,
   color_icons      = true,
   git_icons        = false,

lua/fzf-lua/providers/buffers.lua

@@ -375,24 +375,20 @@ M.tabs = function(opts)
     return msg, hl
   end
 
-  if opts.locate and utils.has(opts, "fzf", { 0, 36 }) then
-    -- Set cursor to current buffer
-    table.insert(opts._fzf_cli_args, "--bind=" .. libuv.shellescape("load:+transform:"
-      .. FzfLua.shell.stringify_data(function(_, _, _)
-        local pos = 0
-        for tabnr, tabh in ipairs(vim.api.nvim_list_tabpages()) do
+  if opts.locate then
+    local pos = 0
+    for tabnr, tabh in ipairs(vim.api.nvim_list_tabpages()) do
+      pos = pos + 1
+      for _, w in ipairs(vim.api.nvim_tabpage_list_wins(tabh)) do
+        local b = filter_buffers(opts, { vim.api.nvim_win_get_buf(w) })[1]
+        if b then
           pos = pos + 1
-          for _, w in ipairs(vim.api.nvim_tabpage_list_wins(tabh)) do
-            local b = filter_buffers(opts, { vim.api.nvim_win_get_buf(w) })[1]
-            if b then
-              pos = pos + 1
-              if tabnr == utils.CTX().tabnr and w == utils.CTX().winid then
-                return string.format("pos(%d)", pos)
-              end
-            end
+          if tabnr == utils.CTX().tabnr and w == utils.CTX().winid then
+            opts.__locate_pos = pos
           end
         end
-      end, opts)))
+      end
+    end
   end
 
   local contents = function(cb)

lua/fzf-lua/providers/lsp.lua

@@ -265,6 +265,13 @@ local function symbol_handler(opts, cb, _, result, ctx, _)
       local entry0 = make_entry.lcol(entry, opts)
       local entry1 = make_entry.file(entry0, opts)
       if entry1 then
+        if opts.locate and not opts.__locate_pos then
+          opts.__locate_count = opts.__locate_count or 0
+          opts.__locate_count = opts.__locate_count + 1
+          if entry.lnum == utils.CTX().cursor[1] then
+            opts.__locate_pos = opts.__locate_count
+          end
+        end
         local align = 48 + mbicon_align + utils.ansi_escseq_len(symbol)
         -- TODO: string.format %-{n}s fails with align > ~100?
         -- entry1 = string.format("%-" .. align .. "s%s%s", symbol, utils.nbsp, entry1)
@@ -755,6 +762,7 @@ end
 M.workspace_symbols = function(opts)
   opts = normalize_lsp_opts(opts, "lsp.symbols", "lsp_workspace_symbols")
   if not opts then return end
+  opts.locate = false -- Makes no sense for workspace symbols
   opts.__ACT_TO = opts.__ACT_TO or M.live_workspace_symbols
   opts.__call_fn = utils.__FNCREF__()
   opts.lsp_params = { query = opts.lsp_query or "" }