Add implementation for improved statusline. Closes #545.

autoload/nvim_treesitter.vim

@@ -2,6 +2,10 @@ function! nvim_treesitter#statusline(len) abort
   return luaeval("require'nvim-treesitter'.statusline(_A)", a:len)
 endfunction
 
+function! nvim_treesitter#named_statusline(...) abort
+  return luaeval("require'nvim-treesitter'.named_statusline(_A)", get(a:, 1, {}))
+endfunction
+
 function! nvim_treesitter#foldexpr() abort
 	return luaeval(printf('require"nvim-treesitter.fold".get_fold_indic(%d)', v:lnum))
 endfunction

doc/nvim-treesitter.txt

@@ -423,6 +423,27 @@ could be used as a statusline indicator.
 Note: The `size` argument is optional. When specified, the string will not be
       longer than `size`.
 
+                                          *nvim_treesitter#named_statusline()*
+nvim_treesitter#named_statusline(opts)~
+
+Returns a string describing the current position in the file. This
+could be used as a statusline indicator.
+Default options (lua syntax):
+>
+  {
+    indicator_size = 100,
+    type_patterns = {'class', 'function', 'method'},
+    transform_fn = function(line) return line:gsub('[%[%(%{]*%s*$', '') end,
+    separator = ' -> '
+  }
+<
+- `indicator_size` - How long should the string be. If longer, it is cut from
+  the beginning.
+- `type_patterns` - Which node type patterns to match.
+- `transform_fn` - Function used to transform the single item in line. By
+  default removes opening brackets and spaces from end.
+- `separator` - Separator between nodes.
+
                                                   *nvim_treesitter#foldexpr()*
 nvim_treesitter#foldexpr()~
 

lua/nvim-treesitter.lua

@@ -53,4 +53,56 @@ function M.statusline(indicator_size)
   end
 end
 
+local get_line_for_node = function(node, type_patterns, transform_fn)
+  local node_type = node:type()
+  local is_valid = false
+  for _, rgx in ipairs(type_patterns) do
+    if node_type:find(rgx) then
+      is_valid = true
+      break
+    end
+  end
+  if not is_valid then return '' end
+  local range = {node:range()}
+  local line = transform_fn(vim.trim(vim.fn.getline(range[1] + 1)))
+  -- Escape % to avoid statusline to evaluate content as expression
+  return line:gsub('%%', '%%%%')
+end
+
+-- Trim spaces and opening brackets from end
+local transform_line = function(line)
+  return line:gsub('[%[%(%{]*%s*$', '')
+end
+
+function M.named_statusline(opts)
+  if not parsers.has_parser() then return end
+  local options = opts or {}
+  local indicator_size = options.indicator_size or 100
+  local type_patterns = options.type_patterns or {'class', 'function', 'method'}
+  local transform_fn = options.transform_fn or transform_line
+  local separator = options.separator or ' -> '
+
+  local current_node = ts_utils.get_node_at_cursor()
+  if not current_node then return "" end
+
+  local lines = {}
+  local expr = current_node
+
+  while expr do
+    local line = get_line_for_node(expr, type_patterns, transform_fn)
+    if line ~= '' and not vim.tbl_contains(lines, line) then
+      table.insert(lines, 1, line)
+    end
+    expr = expr:parent()
+  end
+
+  local text = table.concat(lines, separator)
+  local text_len = #text
+  if text_len > indicator_size then
+    return '...'..text:sub(text_len - indicator_size, text_len)
+  end
+
+  return text
+end
+
 return M