From 3497c6c6b3eead069e408ade1c9ff31f8550d66b Mon Sep 17 00:00:00 2001
From: Dalius Dobravolskas <daliusd@wix.com>
Date: Thu, 22 Dec 2022 15:14:34 +0200
Subject: [PATCH] Passing self as second arg to self.options.fmt (#915)

* Add `tabnr` to `fmt` function

* Passing self as second arg to `self.options.fmt`

* README updated.
---
 README.md                                 | 15 +++++++++++++++
 lua/lualine/component.lua                 |  2 +-
 lua/lualine/components/buffers/buffer.lua |  2 +-
 lua/lualine/components/tabs/tab.lua       |  2 +-
 4 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 4cc47b8..b92f0f9 100644
--- a/README.md
+++ b/README.md
@@ -452,6 +452,11 @@ sections = {
                    --   padding = { left = left_padding, right = right_padding }
 
       fmt = nil,   -- Format function, formats the component's output.
+                   -- This function receives two arguments:
+                   -- - string that is going to be displayed and
+                   --   that can be changed, enhanced and etc.
+                   -- - context object with information you might
+                   --   need. E.g. tabnr if used with tabs.
       on_click = nil, -- takes a function that is called when component is clicked with mouse.
                    -- the function receives several arguments
                    -- - number of clicks incase of multiple clicks
@@ -650,6 +655,16 @@ sections = {
         active = 'lualine_{section}_normal',     -- Color for active tab.
         inactive = 'lualine_{section}_inactive', -- Color for inactive tab.
       },
+
+      fmt = function(name, context)
+        -- Show + if buffer is modified in tab
+        local buflist = vim.fn.tabpagebuflist(context.tabnr)
+        local winnr = vim.fn.tabpagewinnr(context.tabnr)
+        local bufnr = buflist[winnr]
+        local mod = vim.fn.getbufvar(bufnr, '&mod')
+
+        return name .. (mod == 1 and ' +' or '')
+      end
     }
   }
 }
diff --git a/lua/lualine/component.lua b/lua/lualine/component.lua
index 2d04824..a4d9d9b 100644
--- a/lua/lualine/component.lua
+++ b/lua/lualine/component.lua
@@ -272,7 +272,7 @@ function M:draw(default_highlight, is_focused)
   self.default_hl = default_highlight
   local status = self:update_status(is_focused)
   if self.options.fmt then
-    status = self.options.fmt(status or '')
+    status = self.options.fmt(status or '', self)
   end
   if type(status) == 'string' and #status > 0 then
     self.status = status
diff --git a/lua/lualine/components/buffers/buffer.lua b/lua/lualine/components/buffers/buffer.lua
index 618aaca..d5a5a23 100644
--- a/lua/lualine/components/buffers/buffer.lua
+++ b/lua/lualine/components/buffers/buffer.lua
@@ -69,7 +69,7 @@ end
 function Buffer:render()
   local name = self:name()
   if self.options.fmt then
-    name = self.options.fmt(name or '')
+    name = self.options.fmt(name or '', self)
   end
 
   if self.ellipse then -- show ellipsis
diff --git a/lua/lualine/components/tabs/tab.lua b/lua/lualine/components/tabs/tab.lua
index d610c1d..8b76861 100644
--- a/lua/lualine/components/tabs/tab.lua
+++ b/lua/lualine/components/tabs/tab.lua
@@ -51,7 +51,7 @@ end
 function Tab:render()
   local name = self:label()
   if self.options.fmt then
-    name = self.options.fmt(name or '')
+    name = self.options.fmt(name or '', self)
   end
   if self.ellipse then -- show ellipsis
     name = '...'