widget.temp: reset path to /sys/devices; closes #441

[etc/awesome.git] / helpers.lua

diff --git a/helpers.lua b/helpers.lua
index 313579f8a3d28368b4918faf5e0a32f4b9ca9e37..d6f6b3c1fcf861c283fff9134a1b9587a40998cd 100644 (file)
--- a/helpers.lua
+++ b/helpers.lua
@@ -10,8 +10,10 @@ local timer      = require("gears.timer")
 local debug      = require("debug")
 local io         = { lines = io.lines,
                      open  = io.open }
+local pairs      = pairs
 local rawget     = rawget
-local table      = { sort  = table.sort }
+local table      = { sort  = table.sort, unpack = table.unpack }
+local unpack     = unpack or table.unpack -- lua 5.1 retro-compatibility
 
 -- Lain helper functions for internal use
 -- lain.helpers
@@ -32,53 +34,49 @@ end
 
 -- {{{ File operations
 
--- see if the file exists and is readable
-function helpers.file_exists(file)
-  local f = io.open(file)
-  if f then
-      local s = f:read()
-      f:close()
-      f = s
-  end
-  return f ~= nil
-end
-
--- get all lines from a file, returns an empty
--- list/table if the file does not exist
-function helpers.lines_from(file)
-  if not helpers.file_exists(file) then return {} end
-  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)
-    return helpers.lines_from(file)[1]
-end
-
--- get first non empty line from a file,
--- returns nil otherwise
-function helpers.first_nonempty_line(file)
-  for k,v in pairs(helpers.lines_from(file)) do
-    if #v then return v end
-  end
-  return nil
+-- check if the file exists and is readable
+function helpers.file_exists(path)
+    local file = io.open(path, "rb")
+    if file then file:close() end
+    return file ~= nil
+end
+
+-- get a table with all lines from a file
+function helpers.lines_from(path)
+    local lines = {}
+    for line in io.lines(path) do
+        lines[#lines + 1] = line
+    end
+    return lines
+end
+
+-- get a table with all lines from a file matching regexp
+function helpers.lines_match(regexp, path)
+    local lines = {}
+    for line in io.lines(path) do
+        if string.match(line, regexp) then
+            lines[#lines + 1] = line
+        end
+    end
+    return lines
+end
+
+-- get first line of a file
+function helpers.first_line(path)
+    local file, first = io.open(path, "rb"), nil
+    if file then
+        first = file:read("*l")
+        file:close()
+    end
+    return first
+end
+
+-- get first non empty line from a file
+function helpers.first_nonempty_line(path)
+    for line in io.lines(path) do
+        if #line then return line end
+    end
+    return nil
 end
 
 -- }}}
@@ -179,9 +177,8 @@ 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}}.
+-- create the partition of singletons of a given set
+-- example: the trivial partition set of {a, b, c}, is {{a}, {b}, {c}}
 function helpers.trivial_partition_set(set)
     local ss = {}
     for _,e in pairs(set) do
@@ -190,7 +187,7 @@ function helpers.trivial_partition_set(set)
     return ss
 end
 
--- creates the powerset of a given set
+-- create the powerset of a given set
 function helpers.powerset(s)
     if not s then return {} end
     local t = {{}}