menu_iterator: generic menu creator function

[etc/awesome.git] / helpers.lua

diff --git a/helpers.lua b/helpers.lua
index 137bd6ab54f4e36bd051f84e1b1cf39cd515b25f..ce655761405b9a972b58cda4e0e8552052b1daee 100644 (file)
--- a/helpers.lua
+++ b/helpers.lua
@@ -1,19 +1,17 @@
-
 --[[
-                                                  
-     Licensed under GNU General Public License v2 
-      * (c) 2013, Luke Bonham                     
-                                                  
---]]
 
-local debug  = require("debug")
+     Licensed under GNU General Public License v2
+      * (c) 2013, Luke Bonham
+
+--]]
 
-local capi   = { timer = (type(timer) == 'table' and timer or require ("gears.timer")) }
-local io     = { open  = io.open,
-                 lines = io.lines,
-                 popen = io.popen }
-local rawget = rawget
-local table  = { sort   = table.sort }
+local spawn = require("awful.spawn")
+local timer      = require("gears.timer")
+local debug      = require("debug")
+local io         = { lines = io.lines,
+                     open  = io.open }
+local rawget     = rawget
+local table      = { sort  = table.sort }
 
 -- Lain helper functions for internal use
 -- lain.helpers
@@ -49,13 +47,25 @@ end
 -- list/table if the file does not exist
 function helpers.lines_from(file)
   if not helpers.file_exists(file) then return {} end
-  lines = {}
+  local lines = {}
   for line in io.lines(file) do
     lines[#lines + 1] = line
   end
   return lines
 end
 
+-- match all lines from a file, returns an empty
+-- list/table if the file or match does not exist
+function helpers.lines_match(regexp, file)
+       local lines = {}
+       for index,line in pairs(helpers.lines_from(file)) do
+               if string.match(line, regexp) then
+                       lines[index] = line
+               end
+       end
+       return lines
+end
+
 -- get first line of a file, return nil if
 -- the file does not exist
 function helpers.first_line(file)
@@ -77,28 +87,41 @@ end
 
 helpers.timer_table = {}
 
-function helpers.newtimer(_name, timeout, fun, nostart)
-    local name = timeout
+function helpers.newtimer(name, timeout, fun, nostart, stoppable)
+    if not name or #name == 0 then return end
+    name = (stoppable and name) or timeout
     if not helpers.timer_table[name] then
-        helpers.timer_table[name] = capi.timer({ timeout = timeout })
+        helpers.timer_table[name] = timer({ timeout = timeout })
+        helpers.timer_table[name]:start()
     end
     helpers.timer_table[name]:connect_signal("timeout", fun)
-    helpers.timer_table[name]:start()
     if not nostart then
         helpers.timer_table[name]:emit_signal("timeout")
     end
+    return stoppable and helpers.timer_table[name]
 end
 
 -- }}}
 
 -- {{{ Pipe operations
 
--- read the full output of a pipe (command)
-function helpers.read_pipe(cmd)
-   local f = assert(io.popen(cmd))
-   local output = f:read("*all")
-   f:close()
-   return output
+-- run a command and execute a function on its output (asynchronous pipe)
+-- @param cmd the input command
+-- @param callback function to execute on cmd output
+-- @return cmd PID
+function helpers.async(cmd, callback)
+    return spawn.easy_async(cmd,
+    function (stdout, stderr, reason, exit_code)
+        callback(stdout)
+    end)
+end
+
+-- like above, but call spawn.easy_async with a shell
+function helpers.async_with_shell(cmd, callback)
+    return spawn.easy_async_with_shell(cmd,
+    function (stdout, stderr, reason, exit_code)
+        callback(stdout)
+    end)
 end
 
 -- }}}
@@ -117,7 +140,19 @@ end
 
 -- }}}
 
---{{{ Iterate over table of records sorted by keys
+-- {{{ Misc
+
+-- check if an element exist on a table
+function helpers.element_in_table(element, tbl)
+    for _, i in pairs(tbl) do
+        if i == element then
+            return true
+        end
+    end
+    return false
+end
+
+-- iterate over table of records sorted by keys
 function helpers.spairs(t)
     -- collect the keys
     local keys = {}
@@ -134,6 +169,30 @@ function helpers.spairs(t)
         end
     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