crypto/external/bsd/netpgp/dist/bindings/lua/optparse.lua

   1 -- Lua command line option parser.
   2 -- Interface based on Pythons optparse.
   3 -- http://docs.python.org/lib/module-optparse.html
   4 -- (c) 2008 David Manura, Licensed under the same terms as Lua (MIT license)
   5 --
   6 -- To be used like this:
   7 -- t={usage="<some usage message>", version="<version string>"}
   8 -- op=OptionParser(t)
   9 -- op=add_option{"<opt>", action=<action>, dest=<dest>, help="<help message for this option>"}
  10 --
  11 -- with :
  12 --   <opt> the option string to be used (can be anything, if one letter opt, then should be -x val, more letters: -xy=val )
  13 --   <action> one of
  14 --   - store: store in options as key, val
  15 --   - store_true: stores key, true
  16 --   - store_false: stores key, false
  17 --   <dest> is the key under which the option is saved
  18 --
  19 -- options,args = op.parse_args()
  20 --
  21 -- now options is the table of options (key, val) and args is the table with non-option arguments.
  22 -- You can use op.fail(message) for failing and op.print_help() for printing the usage as you like.
  23
  24 function OptionParser(t)
  25   local usage = t.usage
  26   local version = t.version
  27
  28   local o = {}
  29   local option_descriptions = {}
  30   local option_of = {}
  31
  32   function o.fail(s) -- extension
  33     io.stderr:write(s .. '\n')
  34     os.exit(1)
  35   end
  36
  37   function o.add_option(optdesc)
  38     option_descriptions[#option_descriptions+1] = optdesc
  39     for _,v in ipairs(optdesc) do
  40       option_of[v] = optdesc
  41     end
  42   end
  43   function o.parse_args()
  44     -- expand options (e.g. "--input=file" -> "--input", "file")
  45     local arg = {unpack(arg)}
  46     for i=#arg,1,-1 do local v = arg[i]
  47       local flag, val = v:match('^(%-%-%w+)=(.*)')
  48       if flag then
  49         arg[i] = flag
  50         table.insert(arg, i+1, val)
  51       end
  52     end
  53
  54     local options = {}
  55     local args = {}
  56     local i = 1
  57     while i <= #arg do local v = arg[i]
  58       local optdesc = option_of[v]
  59       if optdesc then
  60         local action = optdesc.action
  61         local val
  62         if action == 'store' or action == nil then
  63           i = i + 1
  64           val = arg[i]
  65           if not val then o.fail('option requires an argument ' .. v) end
  66         elseif action == 'store_true' then
  67           val = true
  68         elseif action == 'store_false' then
  69           val = false
  70         end
  71         options[optdesc.dest] = val
  72       else
  73         if v:match('^%-') then o.fail('invalid option ' .. v) end
  74         args[#args+1] = v
  75       end
  76       i = i + 1
  77     end
  78     if options.help then
  79       o.print_help()
  80       os.exit()
  81     end
  82     if options.version then
  83       io.stdout:write(t.version .. "\n")
  84       os.exit()
  85     end
  86     return options, args
  87   end
  88
  89   local function flags_str(optdesc)
  90     local sflags = {}
  91     local action = optdesc.action
  92     for _,flag in ipairs(optdesc) do
  93       local sflagend
  94       if action == nil or action == 'store' then
  95         local metavar = optdesc.metavar or optdesc.dest:upper()
  96         sflagend = #flag == 2 and ' ' .. metavar
  97                               or  '=' .. metavar
  98       else
  99         sflagend = ''
 100       end
 101       sflags[#sflags+1] = flag .. sflagend
 102     end
 103     return table.concat(sflags, ', ')
 104   end
 105
 106   function o.print_help()
 107     io.stdout:write("Usage: " .. usage:gsub('%%prog', arg[0]) .. "\n")
 108     io.stdout:write("\n")
 109     io.stdout:write("Options:\n")
 110     for _,optdesc in ipairs(option_descriptions) do
 111       io.stdout:write("  " .. flags_str(optdesc) ..
 112                       "  " .. optdesc.help .. "\n")
 113     end
 114   end
 115   o.add_option{"--help", action="store_true", dest="help",
 116                help="show this help message and exit"}
 117   if t.version then
 118     o.add_option{"--version", action="store_true", dest="version",
 119                  help="output version info."}
 120   end
 121   return o
 122 end
 123