package/lua/lua-pcre/string.lua

   1 -- --- T2-COPYRIGHT-NOTE-BEGIN ---
   2 -- This copyright note is auto-generated by ./scripts/Create-CopyPatch.
   3 --
   4 -- T2 SDE: package/.../lua-pcre/string.lua
   5 -- Copyright (C) 2006 Juergen "George" Sawinski
   6 --
   7 -- More information can be found in the files COPYING and README.
   8 --
   9 -- This program is free software; you can redistribute it and/or modify
  10 -- it under the terms of the GNU General Public License as published by
  11 -- the Free Software Foundation; version 2 of the License. A copy of the
  12 -- GNU General Public License can be found in the file COPYING.
  13 -- --- T2-COPYRIGHT-NOTE-END ---
  14
  15 require "@RX@"
  16
  17 --[[ TODO -------------------------------------------------------------------
  18  - describe string.{cflags,eflags}
  19  - gsub does not handle eflags
  20 --]] ------------------------------------------------------------------------
  21
  22 --[[ DESCRIPTION ------------------------------------------------------------
  23
  24 This file replaces the default string library routines "find", "gsub",
  25 "gmatch" with mostly similiarly behaving equivalents with regular
  26 expression syntax patterns.
  27
  28 The original functions are stored in the "string.orig" table.
  29
  30 Additional methods:
  31
  32   string.study([<boolean>])
  33
  34     This function causes the string replacement functions to store the
  35     regular expression if the argument is empty or "true". The default
  36     compile and execution flags cannot be changed then, however.
  37
  38     Supplying "false" as argument clears the regular expression store.
  39
  40   string.cflags(...)
  41
  42   string.eflags(...)
  43
  44 --]] ------------------------------------------------------------------------
  45
  46 -- original string library functions
  47 string.orig = {
  48   find   = string.find,
  49   gsub   = string.gsub,
  50   gmatch = string.gmatch,
  51 }
  52
  53 -- default compile and excuation flags
  54 local __default_flags__ = {
  55   compile = nil,
  56   execute = nil,
  57 }
  58
  59 -- string.study -------------------------------------------------------------
  60 local __study__ = nil
  61
  62 local function study_regex_new(pattern)
  63   assert(__study__, "study_regex_new called outside study mode.")
  64
  65   if not __study__[pattern] then
  66     __study__[pattern] = @RX@.new(pattern, __default_flags__.compile)
  67   end
  68
  69   return __study__[pattern]
  70 end
  71
  72 local function regex_new(pattern)
  73   return @RX@.new(pattern, __default_flags__.compile)
  74 end
  75
  76 local RX = regex_new
  77
  78 function string.study(what)
  79   if what == nil then what = true end
  80
  81   if what then
  82     if not __study__ then __study__ = {} end
  83     RX = study_regex_new
  84   else
  85     if __study__ then
  86       for k,v in pairs(__study__) do
  87         v:__gc()
  88       end
  89     end
  90
  91     __study__ = nil
  92     RX = regex_new
  93   end
  94 end
  95
  96 -- string.cflags ------------------------------------------------------------
  97 function string.cflags(...)
  98   if __study__ then error("unable to set compile flags in study mode") end
  99
 100   __default_flags__.compile = @RX@.flags(arg)
 101 end
 102
 103 -- string.cflags ------------------------------------------------------------
 104 function string.eflags(...)
 105   if __study__ then error("unable to set execution flags in study mode") end
 106
 107   __default_flags__.execute = @RX@.flags(arg)
 108 end
 109
 110 -- string.find regex replacement --------------------------------------------
 111 function string.find(str, pattern, start, plain)
 112   local idx_start, idx_end, capture
 113
 114   if plain then
 115     return string.orig.find(s, pat, init, plain)
 116   end
 117
 118   idx_start, idx_end, capture =
 119     RX(pattern):match(str, start, __default_flags__.execute)
 120
 121   return idx_start,idx_end,unpack(capture)
 122 end
 123
 124 -- string.gmatch regex replacement ------------------------------------------
 125
 126 -- simple result table iterator
 127 local function @RX@_next(t)
 128   if t then
 129     local row = t[1]
 130     table.remove(t, 1)
 131
 132     if row then return unpack(row) end
 133   end
 134 end
 135
 136 function string.gmatch(str, pattern)
 137   local t = {} -- table of result tables
 138
 139   local function capture(str, sub) -- record results in t
 140     table.insert(t, sub)
 141   end
 142
 143   -- execute regex
 144   RX(pattern):gmatch(str, capture, __default_flags__.execute)
 145
 146   -- return our own simple iterator
 147   return @RX@_next, t
 148 end
 149
 150 -- string.gsub regex replacement --------------------------------------------
 151 function string.gsub(str, pat, repl, n)
 152   -- FIXME execution flags
 153   return generic_gsub(RX, str, pat, repl, n)
 154 end
 155
 156 -- original lrexlib/gsub.lua:
 157