lib/util.lua

   1 ---------------------------------------------------------------------------
   2 -- Copyright Julien Danjou <julien@danjou.info> 2008
   3 -- Copyright Mason Larobina <mason.larobina@gmail.com> 2010
   4 ---------------------------------------------------------------------------
   5
   6 -- Grab environment we need
   7 local assert = assert
   8 local debug = debug
   9 local io = io
  10 local ipairs = ipairs
  11 local os = os
  12 local pairs = pairs
  13 local pairs = pairs
  14 local rtable = table
  15 local string = string
  16 local type = type
  17 local print = print
  18
  19 -- Utility module for awful
  20 module("util")
  21
  22 table = {}
  23
  24 local xml_entity_names = { ["'"] = "&apos;", ["\""] = "&quot;", ["<"] = "&lt;", [">"] = "&gt;", ["&"] = "&amp;" };
  25 -- Escape a string from XML char.
  26 function escape(text)
  27     return text and text:gsub("['&<>\"]", xml_entity_names) or nil
  28 end
  29
  30 local xml_entity_chars = { lt = "<", gt = ">", nbsp = " ", quot = "\"", apos = "'", ndash = "-", mdash = "-", amp = "&" };
  31 -- Unescape a string from entities.
  32 function unescape(text)
  33     return text and text:gsub("&(%a+);", xml_entity_chars) or nil
  34 end
  35
  36 -- Return the difference of another table as a new table.
  37 -- (I.e. all elements in the first table but not in the other)
  38 function table.difference(t, other)
  39     local ret = {}
  40     for k, v in pairs(t) do
  41         if type(k) == "number" then
  42             local found = false
  43             for _, ov in ipairs(other) do
  44                 if ov == v then
  45                     found = true
  46                     break
  47                 end
  48             end
  49             if not found then rtable.insert(ret, v) end
  50         else
  51             if not other[k] then ret[k] = v end
  52         end
  53     end
  54     return ret
  55 end
  56
  57 -- Join all tables given as parameters.
  58 -- This will iterate all tables and insert all their keys into a new table.
  59 function table.join(...)
  60     local ret = {}
  61     for i = 1, arg.n do
  62         if arg[i] then
  63             for k, v in pairs(arg[i]) do
  64                 if type(k) == "number" then
  65                     rtable.insert(ret, v)
  66                 else
  67                     ret[k] = v
  68                 end
  69             end
  70         end
  71     end
  72     return ret
  73 end
  74
  75 -- Check if a table has an item and return its key.
  76 function table.hasitem(t, item)
  77     for k, v in pairs(t) do
  78         if v == item then
  79             return k
  80         end
  81     end
  82 end
  83
  84 -- Get a sorted table with all integer keys from a table
  85 function table.keys(t)
  86     local keys = { }
  87     for k, _ in pairs(t) do
  88         rtable.insert(keys, k)
  89     end
  90     rtable.sort(keys, function (a, b)
  91         return type(a) == type(b) and a < b or false
  92     end)
  93     return keys
  94 end
  95
  96 -- Reverse a table
  97 function table.reverse(t)
  98     local tr = { }
  99     -- reverse all elements with integer keys
 100     for _, v in ipairs(t) do
 101         rtable.insert(tr, 1, v)
 102     end
 103     -- add the remaining elements
 104     for k, v in pairs(t) do
 105         if type(k) ~= "number" then
 106             tr[k] = v
 107         end
 108     end
 109     return tr
 110 end
 111
 112 -- Clone a table
 113 function table.clone(t)
 114     local c = { }
 115     for k, v in pairs(t) do
 116         c[k] = v
 117     end
 118     return c
 119 end
 120
 121 -- Return true if table `b` is identical to table `a`
 122 function table.isclone(a, b)
 123     if #a ~= #b then return false end
 124     for k, v in pairs(a) do
 125         if a[k] ~= b[k] then return false end
 126     end
 127     return true
 128 end
 129
 130 -- Remove an element at a given position (or key) in a table and return the
 131 -- value that was in that position.
 132 function table.pop(t, k)
 133     local v = t[k]
 134     if type(k) == "number" then
 135         table.remove(t, k)
 136     else
 137         t[k] = nil
 138     end
 139     return v
 140 end
 141
 142 -- vim: ft=lua:et:sw=4:ts=8:sts=4:tw=80