converted metalua.lua into a metalua executable script

bin/metalua

diff --git a/metalua.lua b/bin/metalua
similarity index 94%
rename from metalua.lua
rename to bin/metalua
index eee8e6e..77e0b65 100644
--- a/metalua.lua
+++ b/bin/metalua
@@ -1,5 +1,7 @@
--------------------------------------------------------------------------------
--- Copyright (c) 2006-2013 Fabien Fleutot and others.
+#!/usr/bin/env lua51
+--*-lua-*----------------------------------------------------------------------
+--
+-- Copyright (c) 2006-2014 Fabien Fleutot and others.
 --
 -- All rights reserved.
 --
@@ -88,8 +90,6 @@
     local argv = {...}
     local opts, optind, optarg =
         alt_getopt.get_ordered_opts({...}, alt_getopt_options, long_opts)
-    --pp.printf("argv=%s; opts=%s, ending at %i, with optarg=%s",
-    --          argv, opts, optind, optarg)
     local s2l = { } -- short to long option names conversion table
     for long, short in pairs(long_opts) do s2l[short]=long end
     local cfg = { chunks = { } }
@@ -108,7 +108,6 @@
 
    -------------------------------------------------------------------
    -- Print messages if in verbose mode
-   -------------------------------------------------------------------
    local function verb_print (fmt, ...)
       if cfg.verbose then
          return pp.printf ("[ "..fmt.." ]", ...)
@@ -125,7 +124,7 @@
    if not next(cfg.chunks) and next(cfg.params) then
       local the_file = table.remove(cfg.params, 1)
       verb_print("Param %q considered as a source file", the_file)
-      cfg.file={ the_file }
+      cfg.chunks={ { tag='file', the_file } }
    end
 
    -------------------------------------------------------------------
@@ -135,7 +134,6 @@
       cfg.interactive=true
    end
 
-
    -------------------------------------------------------------------
    -- Run if asked to, or if no --output has been given
    -- if cfg.run==false it's been *forced* to false, don't override.
@@ -182,8 +180,8 @@
    end
    -- The last file returns the whole chunk's result
    if last_file_idx then
-       -- transform  +{ (function(...) -{ast} end)(...) }
-       -- into   +{ return (function(...) -{ast} end)(...) }
+       -- transform  `+{ (function(...) -{ast} end)(...) }`
+       -- into       `+{ return (function(...) -{ast} end)(...) }`
        local prv_ast = code[last_file_idx]
        local new_ast = { tag='Return', prv_ast }
        code[last_file_idx] = new_ast