feat(tabline): add tabline module

Author: arsham

README.md

@@ -3,7 +3,7 @@
 ![GitHub tag (latest by date)](https://img.shields.io/github/v/tag/arsham/arshamiser.nvim)
 ![License](https://img.shields.io/github/license/arsham/arshamiser.nvim)
 
-Neovim status bar, colour scheme, and foldtext function.
+Neovim status bar, colour scheme, foldtext and tabline functions.
 
 1. [Demo](#demo)
 2. [Requirements](#requirements)
@@ -54,6 +54,8 @@ use({
     -- require("arshamiser.heirliniser")
     _G.custom_foldtext = require("arshamiser.folding").foldtext
     vim.opt.foldtext = "v:lua.custom_foldtext()"
+    -- if you want to draw a tabline:
+    vim.api.nvim_set_option("tabline", [[%{%v:lua.require("arshamiser.tabline").draw()%}]])
   end,
 })
 ```
@@ -93,6 +95,8 @@ use({
         -- require("arshamiser.heirliniser")
         _G.custom_foldtext = require("arshamiser.folding").foldtext
         vim.opt.foldtext = "v:lua.custom_foldtext()"
+        -- if you want to draw a tabline:
+        vim.api.nvim_set_option("tabline", [[%{%v:lua.require("arshamiser.tabline").draw()%}]])
       end,
     })
   end,

lua/arshamiser/tabline.lua

@@ -0,0 +1,51 @@
+local function title(bufnr, sel)
+  local bufname = vim.api.nvim_buf_get_name(bufnr)
+  local fname = bufname ~= "" and vim.fn.fnamemodify(bufname, ":t") or "[EMPTY]"
+  local c = "%#TabLine#"
+  if sel then
+    c = "%#TabLineSel#"
+  end
+  return table.concat({ c, (" %s "):format(fname) })
+end
+
+local function modified(bufnr, sel)
+  if vim.api.nvim_buf_get_name(bufnr) == "" then
+    return ""
+  end
+
+  if not vim.api.nvim_buf_get_option(bufnr, "modified") then
+    return ""
+  end
+
+  return table.concat({
+    sel and "" or " ",
+    sel and "%#TabLineModifiedSel#" or "%#TabLineModified#",
+    "●",
+  })
+end
+
+local function separator(sel)
+  return table.concat({ sel and "%#TabLineSepSel#" or "%#TabLineSep#", "▏" })
+end
+
+local function draw()
+  local tabline = {}
+
+  for _, tab in ipairs(vim.api.nvim_list_tabpages()) do
+    local sel = tab == vim.api.nvim_get_current_tabpage()
+    local bufnr = vim.api.nvim_win_get_buf(vim.api.nvim_tabpage_get_win(tab))
+    local label = { ("%%%dT"):format(vim.api.nvim_tabpage_get_number(tab)) }
+    table.insert(label, separator(sel))
+    table.insert(label, title(bufnr, sel))
+    table.insert(label, modified(bufnr, sel))
+    table.insert(label, " %#TabLineFill#")
+
+    table.insert(tabline, table.concat(label))
+  end
+
+  return table.concat(tabline)
+end
+
+return {
+  draw = draw,
+}