refactor: theme.vim --> theme.lua

lua/utils.lua

@@ -31,4 +31,30 @@ function M.get_nvim_version()
   return nvim_ver_str
 end
 
+
+--- Generate random integers in the range [Low, High], inclusive,
+--- adapted from https://stackoverflow.com/a/12739441/6064933
+--- @low: the lower value for this range
+--- @high: the upper value for this range
+function M.rand_int(low, high)
+  -- Use lua to generate random int, see also: https://stackoverflow.com/a/20157671/6064933
+  math.randomseed(os.time())
+
+  return math.random(low, high)
+end
+
+--- Select a random element from a sequence/list.
+--- @seq: the sequence to choose an element
+function M.rand_element(seq)
+  local idx = M.rand_int(1, #seq)
+
+  return seq[idx]
+end
+
+function M.add_pack(name)
+  local status, error = pcall(vim.cmd, "packadd " .. name)
+
+  return status
+end
+
 return M