<aliases>
  <alias
   match="file_convert"
   enabled="y"
   send_to="12"
   sequence="100"
  >
  <send>

-- get input file
local inputname = utils.filepicker ("Choose file to convert")

if not inputname then return end

-- read input file
local f = assert (io.open (inputname, "rb"))
local s = f:read "*a"
f:close ()

-- four forms of delimiter
local delim = lpeg.P (lpeg.P("\\n") * "\\r") + 
        lpeg.P (lpeg.P("\\r") * "\\n") + 
        lpeg.P ("\\n") + 
        lpeg.P ("\\r")

-- conversion function
local function gsub (s, patt, repl)
  patt = lpeg.P(patt)
  patt = lpeg.Cs((patt / repl + 1)^0)
  return lpeg.match(patt, s)
end

local choices    = { 
  ["\\n"]     = "Unix (LF only)", 
  ["\\r\\n"]  = "Dos (CR/LF)",   
  ["\\r"]     = "Mac (CR only)",
   }  -- end choices

-- choose new line-ending type
local delimiter = utils.listbox ("Choose new line endings ...", 
                                 "Format of output file", choices, "\\r\\n")

if not delimiter then return end

-- convert line endings to new format
local converted = gsub (s, delim, delimiter)

-- show stats
print (string.format ("Input  size (%%s) = %%i bytes (%%0.1f Kb).", inputname, #s, #s / 1024))
print ("Output size =", #converted, "bytes.")

-- ask to save
local outputname = utils.filepicker ("File name to save as", inputname, nil, nil, true)

if not outputname  then return end

-- write it
local f = assert (io.open (outputname , "wb"))
assert (f:write (converted))
f:close ()

-- confirmation
print ("Done. Saved as:", outputname)

</send>
  </alias>
</aliases>