Merge pull request #377 from sim590/menu-iterator

menu_iterator: naughty.notify based menu utility

diff --combined helpers.lua
index 6073dddfc435b1b79c5ab81b65912ca8e7e8684f,ce655761405b9a972b58cda4e0e8552052b1daee..313579f8a3d28368b4918faf5e0a32f4b9ca9e37
--- 1/helpers.lua
--- 2/helpers.lua
+++ b/helpers.lua
@@@ -1,11 -1,11 +1,11 @@@
  --[[
  
       Licensed under GNU General Public License v2
 -      * (c) 2013, Luke Bonham
 +      * (c) 2013, Luca CPZ
  
  --]]
  
 -local spawn = require("awful.spawn")
 +local spawn      = require("awful.spawn")
  local timer      = require("gears.timer")
  local debug      = require("debug")
  local io         = { lines = io.lines,
@@@ -112,7 -112,7 +112,7 @@@ en
  function helpers.async(cmd, callback)
      return spawn.easy_async(cmd,
      function (stdout, stderr, reason, exit_code)
 -        callback(stdout)
 +        callback(stdout, exit_code)
      end)
  end
  
@@@ -120,19 -120,10 +120,19 @@@
  function helpers.async_with_shell(cmd, callback)
      return spawn.easy_async_with_shell(cmd,
      function (stdout, stderr, reason, exit_code)
 -        callback(stdout)
 +        callback(stdout, exit_code)
      end)
  end
  
 +-- run a command and execute a function on its output line by line
 +function helpers.line_callback(cmd, callback)
 +    return spawn.with_line_callback(cmd, {
 +        stdout = function (line)
 +            callback(line)
 +        end,
 +    })
 +end
 +
  -- }}}
  
  -- {{{ A map utility
@@@ -179,6 -170,29 +179,29 @@@ function helpers.spairs(t
      end
  end
  
+ -- create trivial partition of a set. The trivial partition set is the simplest
+ -- partition of a set. For e.g., the trivial partition set of {a, b, c}, is
+ -- simply {{a}, {b}, {c}}.
+ function helpers.trivial_partition_set(set)
+     local ss = {}
+     for _,e in pairs(set) do
+         ss[#ss+1] = {e}
+     end
+     return ss
+ end
+ 
+ -- creates the powerset of a given set
+ function helpers.powerset(s)
+     if not s then return {} end
+     local t = {{}}
+     for i = 1, #s do
+         for j = 1, #t do
+             t[#t+1] = {s[i],unpack(t[j])}
+         end
+     end
+     return t
+ end
+ 
  -- }}}
  
  return helpers