WIP: Add tags builtin

lua/telescope/builtin.lua

@@ -904,4 +904,51 @@ builtin.marks = function(opts)
   }):find()
 end
 
+builtin.tags = function(opts)
+  -- TODO(conni2461): Handle opts like no filename, etc
+  opts = opts or {}
+
+  -- TODO(conni2461): Do we have a function like this already?! In plenary for example
+  -- If not put in utils or plenary
+  local function file_exists(file)
+    local f = io.open(file, "rb")
+    if f then f:close() end
+    return f ~= nil
+  end
+
+  if not file_exists('tags') then
+    local answer = vim.fn.input('Tags file does not exists. Do you want to create one? y/[n]')
+    if answer:lower() == 'y' then
+      os.execute('ctags -R --fields=+n')
+    else
+      return
+    end
+  end
+
+  -- TODO(conni2461): Currently has to be generated with --fields=n or --fields=+n to get the line numbers
+  -- Take a look at fzf, how they do it.
+  local results = {}
+  for line in io.lines('tags') do
+    if line:sub(1, 1) ~= '!'then
+      local tag, file, scode, lnum = string.match(line, '([^\t]+)\t([^\t]+)\t(.*)\t*\tline:(%d+)')
+      table.insert(results, {
+        tag = tag,
+        file = file,
+        line = scode,
+        lnum = tonumber(lnum)
+      })
+    end
+  end
+
+  pickers.new(opts,{
+    prompt = 'Tags',
+    finder = finders.new_table {
+      results = results,
+      entry_maker = make_entry.gen_from_ctags(opts),
+    },
+    previewer = previewers.vimgrep.new(opts),
+    sorter = conf.generic_sorter(opts),
+  }):find()
+end
+
 return builtin

lua/telescope/make_entry.lua

@@ -134,7 +134,7 @@ do
   end
 
   local execute_keys = {
-    path = function(t) 
+    path = function(t)
       return t.cwd .. path.separator .. t.filename, false
     end,
 
@@ -572,4 +572,36 @@ function make_entry.gen_from_vimoptions(opts)
   end
 end
 
+function make_entry.gen_from_ctags(opts)
+  opts = opts or {}
+
+  local make_display = function(entry)
+    local display_filename
+    if opts.shorten_path then
+      display_filename = path.shorten(entry.filename)
+    else
+      display_filename = entry.filename
+    end
+
+    -- TODO(conni2461): Write make_entry and make table pretty with new table create
+    return display_filename .. ': ' .. entry.tag .. ': ' .. entry.line
+  end
+
+  return function(entry)
+    return {
+      valid = true,
+
+      ordinal = entry.file .. ': ' .. entry.tag .. ': ' .. entry.line,
+      display = make_display,
+      line = entry.line,
+      tag = entry.tag,
+
+      filename = entry.file,
+
+      lnum = entry.lnum or 1,
+      col = 1,
+    }
+  end
+end
+
 return make_entry