pattern.lua

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