Added other sources for component configuration (#53)

README.md

@@ -157,6 +157,30 @@ lualine.sections.lualine_a = { hello }
 
 </details>
 
+<details>
+<summary><b>Using vim functions as lualine component</b></summary>
+
+You can use vim functions as a lualine component
+
+```
+lualine.sections.lualine_b = { 'FugitiveHead' }
+```
+
+</details>
+
+<details>
+<summary><b>Using variables as lualine component</b></summary>
+
+You can use variables from vim and lua globals as a lualine component
+Variables from g:, v:, t:, w:, b:, o, go:, vo:, to:, wo:, bo: scopes
+can be used. Scopes ending with o are options usualy accessed with `&` in vimscript
+
+```
+lualine.sections.lualine_b = { 'g:coc_status', 'bo:filetype' }
+```
+
+</details>
+
 ### Loading plugin extensions
 Lualine extensions change statusline appearance for a window/buffer with a plugin loaded e.g. [junegunn/fzf.vim](https://github.com/junegunn/fzf.vim)
 

doc/lualine.txt

@@ -34,10 +34,11 @@ CONTENTS                                                     *lualline-contents*
         1.3.2. Setting a theme.........................|lualine-setting_a_theme|
         1.3.3. Changing separator...................|lualine-changing_separator|
         1.3.4. Changing components.................|lualine-changing_components|
-        1.3.5. Loading plugin extensions.....|lualine-loading_plugin_extensions|
+        1.3.5. Building Custom components............|lualine-custom_components|
-	1.3.6  Config examples.........................|lualine-config_examples|
+        1.3.6. Loading plugin extensions.....|lualine-loading_plugin_extensions|
-	    1.3.6.1. Packer.nvim......|lualine-config_example_using_packer.nvim|
+	1.3.7  Config examples.........................|lualine-config_examples|
-            1.3.6.2 VIML example.......|lualine-full_config_example_inside_viml|
+	    1.3.7.1. Packer.nvim......|lualine-config_example_using_packer.nvim|
+            1.3.7.2 VIML example.......|lualine-full_config_example_inside_viml|
     1.4. Contributing.....................................|lualine-contributing|
     1.5. Screenshots.......................................|lualine-screenshots|
 
@@ -162,6 +163,8 @@ Available components~
         *   signify
 
 
+--------------------------------------------------------------------------------
+BUILDING YOUR COMPONENTS			   *lualine-custom_components*
 
 
 Using custom functions as lualine component~
@@ -173,6 +176,25 @@ You can define a custom function as a lualine component
     end
     lualine.sections.lualine_a = { hello }
 <
+Using vim functions as lualine component~
+
+You can use vim functions as a lualine component
+
+>
+    lualine.sections.lualine_b = { 'FugitiveHead' }
+<
+
+Using variables as lualine component~
+
+You can use variables from vim and lua globals as a lualine component
+Variables from g:, v:, t:, w:, b:, o, go:, vo:, to:, wo:, bo: scopes
+can be used. Scopes ending with o are options usualy accessed with `&` in vimscript
+
+>
+    lualine.sections.lualine_b = { 'g:coc_status', 'bo:filetype' }
+    lualine.sections.lualine_x = { 'vim.bo.fileencoding' }
+<
+
 
 --------------------------------------------------------------------------------
 LOADING PLUGIN EXTENSIONS                    *lualine-loading_plugin_extensions*

doc/tags

@@ -4,10 +4,12 @@ lualine-changing_separator	lualine.txt	/*lualine-changing_separator*
 lualine-config_example_using_packer.nvim	lualine.txt	/*lualine-config_example_using_packer.nvim*
 lualine-config_examples	lualine.txt	/*lualine-config_examples*
 lualine-contributing	lualine.txt	/*lualine-contributing*
+lualine-custom_components	lualine.txt	/*lualine-custom_components*
 lualine-full_config_example_inside_viml	lualine.txt	/*lualine-full_config_example_inside_viml*
 lualine-installation	lualine.txt	/*lualine-installation*
 lualine-loading_plugin_extensions	lualine.txt	/*lualine-loading_plugin_extensions*
 lualine-lualine.nvim	lualine.txt	/*lualine-lualine.nvim*
+lualine-nvim	lualine.txt	/*lualine-nvim*
 lualine-packer.nvim	lualine.txt	/*lualine-packer.nvim*
 lualine-performance_comparism	lualine.txt	/*lualine-performance_comparism*
 lualine-screenshots	lualine.txt	/*lualine-screenshots*

lua/lualine.lua

@@ -29,12 +29,52 @@ M.inactive_sections = {
 M.extensions = {
 }
 
+local function load_special_components(component)
+  return function()
+    -- precedence lualine_component > vim_var > lua_var > vim_function
+    if component:find('[gvtwb]?o?:') == 1 then
+      -- vim veriable component
+      -- accepts g:, v:, t:, w:, b:, o, go:, vo:, to:, wo:, bo:
+      -- filters g portion from g:var
+      local scope = component:match('[gvtwb]?o?')
+      -- filters var portion from g:var
+      -- For some reason overwriting component var from outer scope causes the
+      -- component not to work . So creating a new local name component to use:/
+      local component = component:sub(#scope + 2, #component)
+      -- Displays nothing when veriable aren't present
+      local return_val = vim[scope][component]
+      if return_val == nil then return '' end
+      local ok
+      ok, return_val =  pcall(tostring, return_val)
+      if ok then return return_val end
+      return ''
+    elseif loadstring(string.format('return %s ~= nil', component)) and
+       loadstring(string.format([[return %s ~= nil]], component))() then
+      -- lua veriable component
+      return loadstring(string.format([[
+        local ok, return_val = pcall(tostring, %s)
+        if ok then return return_val end
+        return '']], component))()
+    else
+      -- vim function component
+      local ok, return_val = pcall(vim.fn[component])
+      if not ok then return '' end -- function call failed
+      ok, return_val =  pcall(tostring, return_val)
+      if ok then return return_val else return '' end
+    end
+  end
+end
+
 local function load_components()
   local function load_sections(sections)
     for _, section in pairs(sections) do
       for index, component in pairs(section) do
         if type(component) == 'string' then
-          section[index] = require('lualine.components.' .. component)
+          local ok,loaded_component = pcall(require, 'lualine.components.' .. component)
+          if not ok then
+            loaded_component = load_special_components(component)
+          end
+          section[index] = loaded_component
         end
       end
     end