feat: Line numbers next to symbols for quick jumping

See reasoning in:
simrat39/symbols-outline.nvim#212

This feature is turned off by default to avoid clutter, and many users
might not want this feature on by default.

README.md

@@ -80,7 +80,7 @@ features:
 
 ## Features
 
-[Skip this section](#symbols-outlinenvim)
+[Skip to plugin readme](#symbols-outlinenvim)
 
 Below is a list of features I've included in this fork which, at the time of
 writing, has not been included upstream (in the original repo). I try my best to
@@ -99,6 +99,11 @@ Features/Changes:
     - simrat39/symbols-outline.nvim#174
     - simrat39/symbols-outline.nvim#207
 
+- Show line number of each symbol in outline window (see [recipes](#recipes)
+for a screenshot)
+  - Fixed issues:
+    - simrat39/symbols-outline.nvim#212
+
 - Cursorline option for the outline window.
 
 - Added function and command to show provider and outline window status,
@@ -120,7 +125,7 @@ Screen recordings of some of the features is shown at the bottom of the readme.
 
 ## PRs
 
-[Skip this section](#symbols-outlinenvim)
+[Skip to plugin readme](#symbols-outlinenvim)
 
 Key:
 ```
@@ -128,6 +133,9 @@ Key:
 📮 = Planned for merge
 ```
 
+- 📮 center view on goto symbol
+  (#239 by skomposzczet)
+
 - ✅ Open handler checks if view is not already open
   (#235 by eyalz800)
 
@@ -206,7 +214,7 @@ Key:
 
 ## TODO
 
-[Skip this section](#symbols-outlinenvim)
+[Skip to plugin readme](#symbols-outlinenvim)
 
 Key:
 ```
@@ -215,8 +223,6 @@ Key:
 -     : Idea
 ```
 
-Items will be moved to above list when complete.
-
 - Folds
   - `[ ]` Org-like <kbd>shift+tab</kbd> behavior: Open folds level-by-level
   - `[ ]` Optionally not opening all child nodes when opening parent node
@@ -238,7 +244,8 @@ Items will be moved to above list when complete.
 
 - View
   - `[/]` Outline window customizations (simrat39/symbols-outline#137)
-  - `[/]` Option to show line number next to symbols
+  - ✅ Option to show line number next to symbols (simrat39/symbols-outline#212)
+  - `[/]` Option to hide cursor in outline window if cursorline enabled
 
 
 ## Related plugins
@@ -259,6 +266,24 @@ Supports all your favourite languages.**
 
 ![demo](https://github.com/simrat39/rust-tools-demos/raw/master/symbols-demo.gif)
 
+Table of contents
+
+<!-- mtoc start -->
+
+* [Prerequisites](#prerequisites)
+* [Installation](#installation)
+* [Setup](#setup)
+* [Configuration](#configuration)
+    * [Terminology](#terminology)
+    * [Options](#options)
+* [Commands](#commands)
+    * [Lua API](#lua-api)
+* [Default keymaps](#default-keymaps)
+* [Highlights](#highlights)
+* [Recipes](#recipes)
+
+<!-- mtoc end -->
+
 ## Prerequisites
 
 - `neovim 0.7+`
@@ -388,6 +413,11 @@ local opts = {
   show_cursorline = true,  -- Only in this fork
   -- Show extra details with the symbols (lsp dependent)
   show_symbol_details = true,
+  -- Only in this fork.
+  -- Show line numbers of each symbol next to them.
+  -- Why? See this comment:
+  -- https://github.com/simrat39/symbols-outline.nvim/issues/212#issuecomment-1793503563
+  show_symbol_lineno = false,
   -- Highlight group for the preview background
   preview_bg_highlight = 'Pmenu',
   -- Depth past which nodes will be folded by default
@@ -665,3 +695,21 @@ This feature was added by @stickperson in an upstream PR 🙌
 
 https://github.com/hedyhli/symbols-outline.nvim/assets/50042066/3d06e342-97ac-400c-8598-97a9235de66c
 
+
+**Hide the extra details after each symbol name**
+
+```lua
+show_symbol_details = false,
+```
+
+**Show line numbers next to each symbol to jump to that symbol quickly**
+
+```lua
+show_symbol_lineno = true,
+```
+
+The default highlight group is `LineNr`.
+
+<img width="900" alt="image" src="https://github.com/hedyhli/symbols-outline.nvim/assets/50042066/2bbb5833-f40b-4c53-8338-407252d61443">
+
+

lua/symbols-outline/config.lua

@@ -25,6 +25,7 @@ M.defaults = {
   show_relative_numbers = false,
   show_cursorline = true,
   show_symbol_details = true,
+  show_symbol_lineno = false,
   preview_bg_highlight = 'Pmenu',
   winblend = 0,
   autofold_depth = nil,

lua/symbols-outline/parser.lua

@@ -94,6 +94,8 @@ end
 function M.get_lines(flattened_outline_items)
   local lines = {}
   local hl_info = {}
+  local guide_hl_info = {}
+  local lineno_max = 0
 
   for node_line, node in ipairs(flattened_outline_items) do
     local depth = node.depth
@@ -102,8 +104,12 @@ function M.get_lines(flattened_outline_items)
     local line = t_utils.str_to_table(string.rep(' ', depth + marker_space))
     local running_length = 1
 
+    if node.range_start+1 > lineno_max then
+      lineno_max = node.range_start+1
+    end
+
     local function add_guide_hl(from, to)
-      table.insert(hl_info, {
+      table.insert(guide_hl_info, {
         node_line,
         from,
         to,
@@ -184,7 +190,46 @@ function M.get_lines(flattened_outline_items)
 
     node.prefix_length = #string_prefix + #node.icon + 1
   end
-  return lines, hl_info
+
+  local final_hl = {}
+  if config.options.show_symbol_lineno then
+    -- Width of the highest lineno value
+    local max_width = #tostring(lineno_max)
+    -- Padded prefix to the right of lineno for better readability if linenos
+    -- get more than 2 digits.
+    local prefix = string.rep(' ', math.max(2, max_width) - 1)
+    -- Offset to hl_info due to adding lineno on the left of each symbol line
+    local total_offset = #prefix
+    for i, node in ipairs(flattened_outline_items) do
+      lines[i] = prefix .. lines[i]
+      table.insert(final_hl, {
+        hl_info[i][1],                 -- node_line
+        hl_info[i][2] + total_offset,  -- start
+        hl_info[i][3] + total_offset,  -- end
+        hl_info[i][4]                  -- type
+      })
+      node.prefix_length = node.prefix_length + total_offset
+    end
+    if config.options.guides.enabled then
+      for _, hl in ipairs(guide_hl_info) do
+        table.insert(final_hl, {
+          hl[1],
+          hl[2] + total_offset,
+          hl[3] + total_offset,
+          hl[4]
+        })
+      end
+    end
+  else
+    -- Merge lists hl_info and guide_hl_info
+    final_hl = hl_info
+    if config.options.guides.enabled then
+      for _, hl in ipairs(guide_hl_info) do
+        table.insert(final_hl, hl)
+      end
+    end
+  end
+  return lines, final_hl
 end
 
 function M.get_details(flattened_outline_items)
@@ -195,4 +240,18 @@ function M.get_details(flattened_outline_items)
   return lines
 end
 
+function M.get_lineno(flattened_outline_items)
+  local lines = {}
+  local max = 0
+  for _, value in ipairs(flattened_outline_items) do
+    local line = value.range_start+1
+    if line > max then
+      max = line
+    end
+    -- Not padded here
+    table.insert(lines, tostring(line))
+  end
+  return lines, max
+end
+
 return M

lua/symbols-outline/writer.lua

@@ -65,6 +65,26 @@ function M.write_details(bufnr, lines)
   end
 end
 
+function M.write_lineno(bufnr, lines, max)
+  if not is_buffer_outline(bufnr) then
+    return
+  end
+  if not config.options.show_symbol_lineno then
+    return
+  end
+  local maxwidth = #tostring(max)
+
+  for index, value in ipairs(lines) do
+    local leftpad = string.rep(' ', maxwidth-#value)
+    vim.api.nvim_buf_set_extmark(bufnr, ns, index - 1, -1, {
+      virt_text = { {leftpad..value, 'LineNr' } },
+      virt_text_pos = 'overlay',
+      virt_text_win_col = 0,
+      hl_mode = 'combine',
+    })
+  end
+end
+
 local function clear_virt_text(bufnr)
   vim.api.nvim_buf_clear_namespace(bufnr, -1, 0, -1)
 end
@@ -101,8 +121,10 @@ function M.parse_and_write(bufnr, flattened_outline_items)
 
   clear_virt_text(bufnr)
   local details = parser.get_details(flattened_outline_items)
+  local lineno, lineno_max = parser.get_lineno(flattened_outline_items)
   M.add_highlights(bufnr, hl_info, flattened_outline_items)
   M.write_details(bufnr, details)
+  M.write_lineno(bufnr, lineno, lineno_max)
 end
 
 return M