pattern.lua

   1 QuestHelper_File["pattern.lua"] = "Development Version"
   2 QuestHelper_Loadtime["pattern.lua"] = GetTime()
   3
   4 -- The following junk is for building functions to parse strings for various locales.
   5
   6 local varindex, varswap = 0, {}
   7
   8 local function replacePattern(p)
   9   varindex = varindex + 1
  10   local b, e, i = string.find(p, "(%d-)%$")
  11
  12   if i then
  13     -- String contains an index.
  14     p = string.sub(p, 1, b-1)..string.sub(p, e+1)
  15     i = tonumber(i)
  16   else
  17     -- String doesn't contains an index, assume its index is the position we found it in.
  18     i = varindex
  19   end
  20
  21   varswap[i] = varindex
  22
  23   if p == "d" then return "(%d+)" end
  24   if p == "s" then return "(.-)" end
  25
  26   -- Only know about strings and integers. Other types are broken.
  27   assert(false, "Unknown pattern: %"..p)
  28 end
  29
  30 -- Used to cache results, so we don't produce multiple functions for the same string.
  31 local known_patterns = {}
  32
  33 function QuestHelper:convertPattern(pattern)
  34   local result = known_patterns[pattern]
  35
  36   if result then
  37     return result
  38   end
  39
  40   while(table.remove(varswap)) do end
  41
  42   varindex = 0
  43
  44   local pat = string.format("^%s$", string.gsub(pattern, "%%(.-[%%%a])", replacePattern))
  45
  46   if varindex == 0 then
  47     -- The string doesn't contain any variables.
  48     result = self.nop
  49   else
  50     local func =  "local function parse(input)\n"
  51     local linear = true
  52
  53     for i = 1,varindex do
  54       if varswap[i] ~= i then
  55         linear = false
  56         break
  57       end
  58     end
  59
  60     if linear then
  61       -- All the arguments are in order, we can just return them.
  62       func = func .. string.format("return select(3, string.find(input, %q))", pat)
  63     else
  64       -- The order has been changed, use temporary variables.
  65       for i = 1,varindex do
  66         func = func ..(i==1 and "local " or ", ")..("n"..i)
  67       end
  68
  69       func = func .. string.format(" = select(3, string.find(input, %q))\n", pat)
  70
  71       for i = 1,varindex do
  72         func = func ..(i==1 and "return " or ", ")..(varswap[i] and ("n"..varswap[i]) or "nil")
  73       end
  74     end
  75
  76     func = func .. "\nend\nreturn parse\n"
  77
  78     result = loadstring(func)()
  79   end
  80
  81   known_patterns[pattern] = result
  82   return result
  83 end